I heard if two HIV positive people (two men) who want to have sex then they both people must use latex condoms for prevention. I heard that if one HIV positive person could have one strain of the HIV/AIDS virus and the other HIV positive person could have a completely different strain of the HIV/AIDS virus. You could be essentially infecting the other person with the disease if you don't have adequate protection. Is this true?



Yes it is. See below.

Dr. Bob

barebacking risks Mar 19, 2006

Dr. Francino:

Thanks for your response to my questions regarding barebacking. I looked up the BETA articles you suggested and I want to tell you, even though I know a lot about HIV and HIV transmission, I certainly learned a mountain of new information in these articles. I was, impressed with the details on safer sex as it relates to the various forms of sexual activities. But, I was most surprised to learn that there have been virtually no known cases of HIV dual infection in any HIV+ individual who has been positive for more than three years. That would explain why barebacking has not truned out to be the horror clinicians initially thought it would be. In my experience, the overwhelming number of barebackers out there seem to be long-term positives and probably positive for three or more years. Yes, STDs are still a risk. And, certainly, any responsible barebacker (if that is not an oxymoron) should stay away from partners who are newly infected. I also understand that this phenomenom of no coinfections after three years) is a source of great interest to scientists in finding a vaccine for HIV. I hope you will print this and suggest that everyone out there do their own research, as well. Keep up the good work.

Response from Dr. Frascino


Yes, I agree BETA did a fine job with their article, which is why I gave you the whole reference rather than just trying to summarize the key points. I'll reprint it below for those readers who may have had difficulty downloading the reference.

Stay well. Stay informed.

Dr. Bob

Dual HIV Infection

A number of individuals infected with more than one strain of HIV have been identified over the past few years. Should people already diagnosed with HIV be concerned? Given the limited number of cases seen so far, the risk of multiple infections (also called dual infection) appears to be quite low. And there are many more pressing health concerns facing people living with HIV/AIDS. Nevertheless, two trends are worth noting: dual infection seems more likely to happen under certain conditions, and it is associated with faster progression to AIDS-related events. This article describes current evidence and theories behind this emerging phenomenon. Coinfection, or infection with more than one viral strain at or near the same time, is believed to occur around the time of initial infection. (Initial infection is also known as acute or primary infectionthe period before seroconversion that usually lasts from a few weeks to a few months.) Reinfection with a different strain, also known as superinfection or serial infection, presumably takes place later on during early infection (the first few years of HIV disease, after seroconversion) or chronic (long-term) infection. Researchers make a distinction between two types of dual, or multiple, HIV infection: Gathering Evidence Experts once hoped that a single HIV infection would prevent further infections, much like a vaccination. In the mid-1990s, however, studies using analogous viruses in primates showed that sequential infections were possible. Some people believed it was only a matter of time before something similar would be seen in humans. Compelling evidence of dual HIV infection in humans appeared in 2002. A report in the Journal of Virology in August of that year strongly suggested reinfection in two injection drug users (IDUs) from Thailand (one female, one male). The woman was initially diagnosed with HIV subtype AE only, followed by detection of subtype B approximately two months later. The man was apparently reinfected with subtype AE virus approximately six to ten months after his primary diagnosis with subtype B virus. Neither individual was being treated for HIV during the study period. In the September 5, 2002 issue of the New England Journal of Medicine, researchers from the University of Geneva reported on a man initially diagnosed with subtype AE virus in November 1998 whose viral load became undetectable (below 50 copies/mL) with antiretroviral therapy. He stopped treatment in January 2001 and shortly thereafter traveled to In theory, any apparent case of reinfection could be a case of coinfection in which one of the coinfecting strains remains undetectable until it emerges sometime after seroconversion (the point at which HIV antibodies can be detected and a person can be diagnosed as being HIV positive). This is sometimes called sequentially expressed coinfection. Testing limitations that prevent detection of very small viral populations in the body make it difficult to distinguish between coinfection and reinfection. Researchers believe that until a source partner for dual infection is found and the timing of exposure confirmed, it is not possible to determine that the second virus was acquired after seroconversion. While finding source partners is a continual problem, determining the timing of exposure is aided in some cases by the emergence of acute retroviral syndrome (often flu-like symptoms, including fever and fatigue) in the person presumed to be reinfected. It is not known whether overgrowth of a previously dormant coinfecting strain might also trigger acute retroviral syndrome. COINFECTION AND REINFECTION WINTER 2006 BETA 37 Brazil, where he had multiple unprotected sexual contacts. In April 2001, three weeks after his return from South America, his viral load spiked to 400,000 copies/mL and he reported symptoms of acute retroviral syndrome, which can signal a new HIV infection. Lab tests subsequently detected a second strain of HIV subtype B, which is common in Brazil. The researchers concluded that reinfection had occurred. More recently, Davey Smith, MD, of the University of California at San Diego and colleagues reported in the August 12, 2005 issue of AIDS that a man with wild-type (drug-sensitive) subtype B virus was apparently reinfected about a year after his first infection with a different subtype B virus resistant to protease inhibitors, which he had never taken, and 3TC (lamivudine, Epivir), which he started only after the second infection. Another case of dual infection with two subtype B viruses with discordant drug sensitivity was reported by the same research group in 2003. In that case, however, the subject was first diagnosed with drug-resistant subtype B virus and then found to have wildtype HIV of the same subtype four months later. Like the man in the 2005 report, this individual had not taken antiretroviral therapy before the apparent reinfection event. Other cases of multiple HIV infection have been identified in the past four years, although the total number remains smallonly 16 apparent reinfections by one measure (a 2005 Medscape survey of the scientific literature done by a group from the Gladstone Institute of Virology and Immunology in San Francisco). The Gladstone researchers, however, did not consider cases of coinfection. In addition, dual infection rates may be higher than reported, since few people with HIV have been tested for multiple strains. Only larger future studies using more sophisticated technologies and better tracking of source partners can provide a clearer picture of the incidence (rate of new cases) and prevalence (total number of existing cases) of coinfection and reinfection in a given population. Impact on Disease Progression Dual infection in humans has been linked to disturbances in immune control and poorer prognosis. In the case of the man who traveled to Brazil, the emergence of his subtype B virus while off therapy coincided with a loss of 300 CD4 cells/mm3 and a dramatic rebound in viral load before he resumed highly active antiretroviral therapy (HAART) four months later. HIV Recombination Different varieties, or strains, of HIV are grouped in a hierarchy. At the broadest level are the two types of HIV: HIV-1 (most prevalent worldwide) and HIV-2 (rare except in West Africa). HIV-1 is divided into three groups:M (major), N (new), and O (outlier). Group M is by far the most common of the three, and is itself subdivided into different clades or subtypes: AD, F, G, H, J, and K. Different subtypes can infect a cell and create hybrid or recombinant forms, such as AC (or A/C). Circulating recombinant forms, or CRFs, are genetically mixed subtypes (such as CRF02_AG) that are found in more than one person. Types HIV-1 HIV-2 | Groups M N O | Subtypes A B C D [E]* F G H J K (Clades) | recombinant forms and CRFs * E does not exist on its own, although it appears in certain CRFs Most recombination events seen thus far are between different subtypes. But infection with two genetically distinct viruses of the same subtypefor example, two subtype B virusesis also possible. The potential for recombination among these is unknown. At the same time, science has yet to reveal what might result from viral mixing among different HIV groups or types. But research opportunities might come soon. At the 2005 Retrovirus conference, a French team claimed to have detected the first reinfection of a group O-infected woman with a virus from group M. Almost more remarkably, the research group located the source of her second infection, the gold standard for confirming secondary infection that has eluded other investigators. While it is generally believed that dual infection must occur for a recombinant virus to be formed, an unusual case of viral recombination in a singly infected woman was reported at the 3rd IAS conference this past July. B. Weiser of the New York State Department of Health and colleagues found that this individual's drug-sensitive HIV evolved differently in her plasma and genital tract after starting HAART and recombined into a multidrug-resistant strain within six months. Viral recombination might play a significant role in accelerating HIV disease (see sidebar on page 37). Recombination increases viral diversity more rapidly than mutations that evolve slowly through replication errors. Recombinant viruses may be less sensitive to anti-HIV drugs and are potentially more virulent than nonrecombinant viruses. This might result from altered tropismspecifically, the virus' ability to use the CXCR4 coreceptor to enter cells, as was the case in the New York man; CXCR4-using viruses are associated with worse disease outcomes than viruses that use the CCR5 coreceptor. Genetically mixed viruses might also be more adept at evading immune responses in a type of evolutionary strategy. At the 3rd International AIDS Society (IAS) conference this past July, Carolyn Williamson, PhD, from the University of Cape Town and colleagues reported finding recombinant virus in six of six dually infected subjects, along with evidence of viral evasion of cellular immune defenses and neutralizing antibodies. The South African team proposed that dual infection "enables recombination to contribute significantly to viral adaptation to immune responses...and may help explain rapid disease progression." Alternatively, the link between dual infection and disease progression might be a product of individual characteristics. Gottlieb has speculated about whether certain people who are inherently predisposed to faster disease progression may also be more susceptible to reinfection. His team noted in their 2004 report, for example, that the one subject believed to be reinfected "had rapid CD4 decline immediately after initial infection, suggesting a host susceptibility to infection with a second virus." Susceptibility and Protection As to when reinfection might occur, data collected so far show an interesting trend. Researchers at the Gladstone Institute pointed out in In a report from 2004, Smith and colleagues analyzed the two dual infection cases mentioned above plus a third man with apparent secondary infection (wild-type followed by drugresistant virus). Among the three men, CD4 cell counts dropped an average of 132 cells/mm3 within six months of acquiring the second strain, while viral load levels increased an average of 1.6 logsa 40-fold increase. Geoffrey Gottlieb, MD, of the University of Washington in Seattle and colleagues retrospectively located five individuals with dual infection (four U.S. gay men, one female sex worker from South Africa). Four were coinfected near the time of seroconversion, while the other was reinfected 1.3 years after initial infection. All five had rapid disease progression: from seroconversion to below 200 CD4 cells/mm3 within 3.1 years on average, and to an AIDS diagnosis or death within 3.4 years. Time from seroconversion to AIDS typically takes 810 years in untreated individuals. In a letter to The Lancet in June 2005, Gottlieb proposed that the case of unusually rapid HIV disease progression in a New York City man described by local health officials in February 2005 might also be due to dual infection rather than the emergence of a so-called "supervirus" (see "News Briefs" on page 4). Several factors might explain an association between dual infection and a surge in HIV disease progression. For now, these are hypothetical and could be related to viral dynamics and the way the second virus attacks the immune system or evades immune responses. Acquiring a drug-resistant viral strain, for instance, would increase the likelihood of losing a response to antiretroviral therapy. This was seen in Smith's 2005 report as well as others. For those not on treatment, overwhelming a drug-resistant virus (considered less able to replicate) with a new wild-type virus (considered more virulent) could result in a higher viral load and speed progression of disease. 38 BETA WINTER 2006 their survey of the literature that multiple infections have not been reported in anyone beyond three years after his or her first infection. (Only a female sex worker from Kenya with recombinant AC virus might have been reinfected after three years, but the exact date is unknown due to a nine-year gap in blood sampling.) This observation has been borne out in recent studies in which dual infection was not observed in chronically infected individuals, even among IDUs who consistently shared needles and HIV positive individuals who had partners with different strains and high risk of re-exposure. While this trend may be an inaccurate observation based on coincidence or testing errors, it has also been seen in primates. A study done in the late 1990s by Ron Otten, PhD, and colleagues from the Centers for Disease Control and Prevention (CDC) showed that macaque monkeys could be infected with two strains of HIV-2 up to four weeks after a first infection, but not between eight and 72 weeks afterwards. Humans might have a similar window of susceptibility to reinfection of approximately three years. The lack of evidence for dual infection during chronic (long-term) HIV disease suggests a protective mechanism at work, such as immune responses that evolve over time or "viral interference"the ability of the original virus to ward off acquisition of another. Any protective role played by anti-HIV therapy in chronic infection would appear to be negligible, since multiple infections have not been reported in untreated chronically infected people after three years. Dual infection therefore seems to occur only during acute or early infection and in these cases, anti-HIV therapy might well make a difference. Evidence suggests that multiple infections happen only in people with acute or early infection who are not being treated or only intermittently treated with anti-HIV drugs. This implies that antiretroviral therapy has WINTER 2006 BETA 39 given the small number of cases? Should people with early HIV disease be counseled to start treatment to avoid reinfection, even if their virus is under control? What impact will reinfection have on HIV positive individuals who "serosort," or choose to have sex only with other positive people? Will those with chronic infection feel freer to have unprotected sex despite the risk of acquiring other sexually transmitted infections (STIs)? As always, the best guide to risk management is reliable information. The Gladstone researchers wisely counsel that "clinicians and researchers should provide balanced and broad views of the risks of unprotected sex between HIV-1 infected persons, and avoid exaggerated or sensational claims about superinfection that could undermine behaviors such as serosorting and serodisclosure that can help to curtail the spread of HIV." Beliefs about multiple infections can affect behavior. In interviews with 193 HIV positive men who have sex with men (33% Latino, 29% African American), researchers from the San Francisco Department of Public Health reported in 2003 that the 83% who believed reinfection was damaging to health were significantly less likely to report unprotected anal sex with an HIV positive partner or any partner compared with those who did not share this belief. Vaccine Design Recent dual infection news has been sobering for vaccine researchers, who study the mechanisms the immune system uses to control pathogens (disease-causing organisms) and work to develop agents that will elicit the same immune responses. The specific protective mechanisms, or "correlates of protection," necessary to subdue HIV are unknown, which has been a major obstacle in HIV vaccine research since the beginning of the epidemic. The task is now made more difficult by the knowledge that the immune system cannot reliably prevent reinfection a protective effect, at least during early HIV disease, either in blocking secondary infections or in preventing certain coinfecting strains from asserting themselves. Antiretroviral agents used as pre-exposure prophylaxis (PREP), taken before a high-risk incident, might work in a similar way to block a first infection. However, using anti-HIV agents as PREP remains experimental and unproven. Although continuous antiretroviral therapy (during early disease) and chronic infection (regardless of treatment) each appear to provide protection against dual infection, more research is needed to understand and confirm these observations. Studies are likewise needed to identify any individual characteristics that might make some people more prone to acquiring a second virus. These factors are currently unknown, although cases such as the one described by Gottlieb in 2004 point to the possibility. Managing Dual Infection The appearance of genetically distinct viruses within an individual complicates the management of HIV disease. Because multiple infections often lead to signs of accelerated disease progression, the typical clinical response has been to begin or resume anti-HIV treatment. Some people among the recently documented cases have controlled their secondary infection with standard antiretroviral therapy. Others, even if responding well to a first regimen before reinfection, have required salvage or rescue regimens containing four or more drugs. Resistance tests may help guide clinicians in their choice of therapy. Newer drugs and drug classes might likewise improve the chances of treatment success, especially in cases of secondary infection with a drugresistant virus. The current understanding of dual infection raises complex questions for people with HIV, clinicians, and prevention workers alike. What approach, if any, should be taken even when responding vigorously to an initial infection. At the 2003 Retrovirus conference, for example, Todd Allen, PhD, of Massachusetts General Hospital and colleagues reported that a robust and specific immune response to one HIV subtype (B) did not inhibit reinfection with another. The fact that virus-specific immune responses are unable to stop other invading viruseseven those of the same subtype, as seen in the cases reported by Smith's groupsuggests that priming the immune system with a vaccine to control one viral subtype will not be sufficient, and that designing a vaccine broadly protective against a range of HIV strains might be impossible. Still, with the added challenge comes a silver lining: the apparent protection afforded by chronic infection, antiretroviral drugs, or individual characteristics. Figuring out how these or other factors allow the immune system to prevent dual infection could be a significant breakthrough and may help guide researchers toward their elusive goal. Given the moribund state of HIV vaccine development, no time should be wasted in exploring this possibility. Conclusion What little is known about dual infection has been sketched from a handful of case reports. Uncertainty will prevail until scientists resolve the issue of whether reinfection occurs independently of coinfection. If all dual infections are in fact coinfections acquired at or near the same time, there would theoretically be no risk of later being reinfected with a second strain of HIV. Studies would then focus on why, when, and in whom coinfection takes place, as well as why some coinfecting HIV strains emerge virulently and only during early infection. If, however, reinfection is a distinct phenomenon, researchers will need to determine precisely what conditions are necessary for multiple infections to occur, who might be 40 BETA WINTER 2006 more susceptible to them, and what are the clinical implications. Only a fuller understanding of dual infection can help people with HIV make informed decisions about risk. (For information about the Positive Partners study, which looks at whether reinfection occurs between sexual partners, see "Open Clinical Trials" on page 54.) And, with luck, investigating the dynamics of multiple infections might lead to the ultimate protection: an HIV vaccine. Nicholas Cheonis is the former editor of BETA. Selected Sources Allen, T.M. and others. HIV-1 superinfection despite broad CD8+ T-cell responses containing replication of the primary virus. 10th Conference on Retroviruses and Opportunistic Infections (CROI). Boston. February 1014, 2003. Abstract 307. Blackard, J.T. and others. Human immunodeficiency virus superinfection and recombination: current state of knowledge and potential clinical consequences. Clinical Infectious Diseases 34(8): 11081114. April 15, 2002. Gottlieb, G.S. and others. Dual HIV-1 infection associated with rapid disease progression. The Lancet 363(9409): 619622. February 21, 2004. Jost, S. and others. A patient with HIV-1 superinfection. New England Journal of Medicine 347(10): 731736. September 5, 2002. Marcus, J.L. and others. HIV superinfection vs dual initial infection: what clinicians and patients should know. Medscape 11(1). 2005. Accessed November 4, 2005. Otten, R.A. and others. Identification of a window period for susceptibility to dual infection with two distinct human immunodeficiency virus type 2 isolates in a Macaca nemestrina (pig-tailed macaque) model. Journal of Infectious Diseases 180(3): 673684. September 1999. Plantier, J.C. and others. HIV-1 group M superinfection in a HIV-1 group O-infected patient. 12th CROI. Abstract 288. Ramos, A. Intersubtype human immunodeficiency virus type 1 superinfection following seroconversion to primary infection in two injection drug users. Journal of Virology 76(15): 74447452. August 2002. Smith, D.M. and others. HIV drug resistance acquired through superinfection. AIDS 19(12): 12511256. August 12, 2005. Weiser, B. and others. Multidrug resistant HIV-1 resulting from intrapatient viral recombination. 3rd International AIDS Society (IAS) Conference on HIV Pathogenesis and Treatment. Rio de Janeiro. July 2427, 2005. Abstract MoFo0306. Williamson, C. and others. Lower rates of adaptive evolution in HIV-1 dual infections compared to single infections. 3rd IAS Conference. Abstract MoFo0305.

Undetectable Viral Load Infection and Superinfection (FINDINGS SUGGEST HIV CAN BE TRANSMITTED FROM MSM WITH UNDETECTABLE VIRAL LOAD 2009) (SUPERINFECTION, 2009) Apr 7, 2009

Thanks for your comments and information about the possibility that people with undetectable viral might be able to infect HIV negative people and contribute to HIV superinfection, but is there any research revealing the actual numbers of such infections and the probability of being infected under such circumstances and being infected with a superinfection?

Response from Dr. Frascino


No, we do not have reliable information as to how often this phenomenon occurs. As you can probably imagine it is quite challenging to conclusively prove that a particular strain of HIV was transmitted to an already infected individual. This requires specialized, labor-intensive and highly expensive laboratory analysis. What has been conclusively proven is that HIVers with an undetectable HIV plasma viral load can transmit their virus to others. Generally speaking it is felt that superinfections (dual infections) are not frequent and are most likely to occur early in the course of the disease. However, even if the frequency is confirmed to be low, it's still a risk I certainly would neither recommend nor personally take.

Dr. Bob


recently alot of bareback videos have come on the market which i love watching. i am poz and was always told dont bareback you can change your strain and become resistance to your current meds, "atripla" by the way and undetectable. but how can porn stars and even close friends of mine that are poz continue to bareback as a bottom and have the top ejaculate in them and have for years and my friends say it has never interferred with there viral loads and they have stayed undetectable and some of my friends have multiple partners at bathouses and they are still fine this perplexes me i read the recent article following poz couples that are undetectable and how they did not get a super infection, so what is your take on all this? now keep in mind yes a couple of my close friends bareback but not without have gotten other std's but never a increase in viral load or med failure. recently i was in L.A and went to a bathouse and it seemed everybody was barebacking and not only did this place offer hiv testing but also viral load testing and it said to see if you have been recently re-infected again. huh? whats the deal? keep in mind i am 37 and only been poz for 16months so a little naive to it all.. thanks love, love, love you and all your words of wisdom and knowledge of the matter...

Response from Dr. Frascino


Your friends are playing sexual Russian roulette. I'm sure they are happy to share their experiences of playing Brokeback Mountain with HIV-positive cowboys riding their rawhides (so to speak) without any negative consequences. However, do you really think they would tell you (or anyone) if their viral load shot up and suddenly they had to switch regimens? Probably not, or at least they'd be much less likely to broadcast such news. Perhaps that's why you haven't heard about it but HIV specialists have.

The possibility of contracting a different and perhaps more virulent strain of HIV is true. Exactly how often this occurs is difficult to tell. (See below.) As for positive couples with undetectable viral loads barebacking and not acquiring a superinfection, see the article below that suggests HIV transmission can occur despite having an undetectable HIV plasma viral load.

The level of risk you want to take is always up to you; however, I can advise you the risk of superinfection is a risk I certainly would not advise or be willing to take. Even though you are a relative newbie to the virally enhanced world, perhaps you could do your friends a favor by passing this information on to them.

Good luck.

Dr. Bob


friend on arv for 2 years says he is no longer contagious is this possible

Response from Dr. Frascino


No. If he's HIV positive, he's capable of transmitting the virus. He may be confused about the terminology of his laboratory tests. On antiretroviral drugs, it is possible (and desirable) to drive his HIV plasma viral load to "undetectable" levels. However, this does not mean he is noninfectious or unable to transmit the virus to others. See below.

Dr. Bob


Hi --

I am an HIV+ man who seroconverted within the last year. I recently started dating another HIV+ man who has been positive for 22 years. I'm currently not on meds with a viral load under 400 and CD4 over 600. His viral load is undetectable and CD4 is 400+. At this point we are having unprotected oral sex and protected anal sex. In the future, we have discussed having unprotected anal sex when we both feel comfortable with our monogamous status. I know there is a risk of other STDs. However, if we've been monogamous and clear of STDs and decide to have unprotected anal sex, am I at any risk of acquiring a resistant strain of the virus if he is on meds and undetectable and I am not on meds? What about if I am on meds? Resistance tests reveal that I have no resistances to treatment.

Thanks so much for your time. This forum is a wonderful resource for the community.

Response from Dr. Frascino


This issue comes up frequently. (See below.) I have no new information to report. I would still advise against Brokeback Mountain barebacking no matter how hot your cowboy may be in the saddle.

Dr. Bob

??? (Findings Suggest HIV Can Be Transmitted From MSM With Undetectable Viral Load, 2008) Oct 23, 2008

Hi I'm 25 and HIV positive Ive been doing fine on atripla once a day and vitamins Ive been poz for 4 years now.The question that i have is that Ive been dating someone that is also positive But only dated since 07 my levels are undetectable i go to the doctor's every 3 months or as needed ,but I'm not sure what my partners levels are and we have been having unprotected sex together hes not on meds, but is always getting colds and just recently told me that he had a UTI hes had other partners but thinks its me because i take meds ,i haven't had any problems so far and i wanted to know if its anyway that I'm making him sick because I'm taking atripla ? .thank u

Response from Dr. Frascino


You are wondering if you are making your bareback-Brokeback-Mountain sex buddy sick, because you are taking Atripla??? WHAT???? No, of course not. However, you are both taking considerable risk by deciding to go commando-Rambo between the sheets. Not only are you both at risk for a wide variety of STDs, but you could also acquire each other's strain of HIV, which could have a very deleterious effect on your health. It is true that driving your HIV plasma viral load to undetectable levels with antiretroviral drugs decreases the risk you would transmit HIV to your partners, but it does not completely eliminate the risk. (See below) I urge you both to reconsider your decision to have unsafe sex, even if you are "serosorting." (See below.)

Dr. Bob

Findings Suggest HIV Can Be Transmitted From MSM With Undetectable Viral Load

Infectiousness and antiretroviral therapy: reports look set to further fuel the debate

Michael Carter, Wednesday, August 27, 2008

A man transmitted HIV to his regular male partner despite taking antiretroviral treatment and having an undetectable viral load in his blood, German doctors report in the journal Antiviral Therapy. The authors believe that this is the first recorded instance of an individual with an undetectable viral load infecting a sexual partner with HIV.

In an editorial accompanying the case report, two of the authors of what has come to be known as the "Swiss Statement", whilst acknowledging a "very low" risk of transmission from individuals taking antiretroviral therapy with an undetectable viral load, highlight what they believe to be some weaknesses in the documentation of this case. Furthermore, they point out that in their own experience "all suspected cases of transmission during antiretroviral therapy turned out to have another source."

And a separately published study looks likely to further fuel the already fierce debate about the infectiousness (or otherwise) of patients being treated with antiretroviral drugs. French investigators report in the August 20th edition of AIDS that 5% of antiretroviral-treated men with an undetectable viral load in their blood had detectable HIV in their semen. None of these men had a sexually transmitted infection.

In January this year, senior HIV doctors in Switzerland issued a statement saying that HIV-positive patients treated with antiretroviral drugs with good adherence to their treatment, a viral load below 40 copies/ml for at least six months, and no sexually transmitted infections should not be considered capable of transmitting HIV sexually. The statement has proved controversial and there was a lively debate about the infectiousness of patients taking successful antiretroviral therapy at the recent International AIDS Conference in Mexico City.

The conference was also told that the lowest blood viral load in a documented case of HIV transmission was approximately 300 copies/ml. But now doctors in Germany have reported a case of transmission when a patient taking antiretroviral therapy had a sustained undetectable viral load in his blood.

The case involved a 39 year-old gay man who first started HIV treatment in 1999. Since 2000 he had been taking a combination of anti-HIV drugs including AZT, 3TC and nevirapine and had maintained an undetectable viral load. Since 2000 this patient had been in a reportedly monogamous relationship with a man of the same age.

The patient's partner reported having had had an anonymous HIV test in 2002, and a search of the records of anonymous tests conducted at the facility the patient attended showed that only one anonymous test was performed on a man at this time, the result being negative . The couple reported unprotected anal intercourse on a number of occasions since May 2003. There is no information in the case report about whether the patient and his partner were insertive, receptive, or both, and the authors failed to clarify this issue when contacted by e-mail.

In July 2004, the patient's partner was diagnosed with HIV, and tests conducted shortly after showed that his CD4 cell count was 338 cells/mm3 and his viral load 21,800 copies/ml. Such a viral load would have been modest for an individual experiencing HIV seroconversion.

The investigators performed phylogenetic analysis which suggested a close relationship between the virus in the patient and his partner. Neither partner reported a sexually transmitted infection.

"We feel confident", write the report's authors, "that the present case report suggests that transmission can occur despite undetectable plasma viral load. Therefore, we cannot support any recommendations that abandon the use of safer-sex practices in this context without mentioning the possibility of HIV transmission."

But the authors of the editorial accompanying the case report highlight what they believe are some weaknesses with the reporting of the case. Although they acknowledge that the phylogenetic analysis indicated a linkage between the virus in the two individuals, they write "an infection by an epidemiologically linked third individual is only ruled out by sexual history, which is notoriously unreliable". They also suggest that "the recollection of a non-documented HIV antibody test more than 5 years earlier is a considerable weakness of this report."

However, the editorial's authors also believe that even a well-documented case report of sexual transmission of HIV involving a patient taking anti-HIV drugs with an undetectable viral load would "not indicate that this practice is associated with a risk of sufficient magnitude to have public health implications." They draw an analogy with oral sex, where individual cases of HIV transmission have been reported.

Detectable viral load in semen when viral load is undetectable in blood

A separate French study has found that 5% of 145 HIV-positive men enrolled in an assisted conception study had detectable viral load in their semen, despite having an undetectable viral load in their blood.

The men provided paired blood and semen samples between 2002 and January 2008. The lower limit of detection for HIV in blood was 40 copies/ml and 200 copies/ml for semen. In the vast majority of samples (85%), HIV was undetectable in both blood and semen.

But in 3% of samples HIV was detectable in both body fluids, and in 6% viral load was undetectable in semen, but detectable in blood. The remaining 5% of paired samples showed that HIV was undetectable in blood, but detectable in semen.

The investigators note that the patients in this 5% had all been taking antiretroviral therapy for at least six months and had maintained a blood viral load below 40 copies/ml. Furthermore none of these patients had a documented sexually transmitted infection.

On the basis of these findings the investigators conclude, "for serodiscordant couples with a desire to have a child, assisted reproduction technology remains a preferred method, when accessible to avoid HIV transmission".


Sturmer M et al. Is transmission of HIV-1 in non-viraemic serodiscordant couples possible? Antiviral Therapy 13: 729 732, 2008.

Vernazza P et al. HIV transmission hunting the chase for low risk events. Antiviral Therapy 13: 641 - 642, 2008.

Marcelin A-G et al. Detection of HIV-1 RNA in seminal plasma samples from treated patients with undetectable HIV-1 RNA in blood plasma. AIDS 22: 1677 79, 2008.

Really concerned about reinfection (SUPERINFECTION, DUAL INFECTION, 2008) Aug 16, 2008

Dr. Bob

I have been HIV poz for a year now. My concern is for the last 2 months I have have unprotected sex with 2 people 1 twice and the other 2 times. They were both HIV poz my worry is we didn't use condoms and they caused me to bleed. One is taking Atripla the same meds I am taking and is un detectable and the is very healthy and undetetable too. What are the odds that I got reinfected. I don't drink or do drugs. I have been stupid. Should I be freaking out right now. I haven't told my doctor as I am ashamed and embarrassed because I am usually extremly safe and cautious I even read about the reinfection. Please help.

Thanks a very worried person

Response from Dr. Frascino


You had unprotected sex with "2 people 1 twice and the other 2 times"???? Wouldn't that be having sex with 2 people both twice??? No matter, on with your question!

HIV reinfection (dual infection) can occur. However, exactly how often this actually happens is difficult to assess. It appears to happen more frequently in early-stage infection. That your 2x2 guys both have undetectable plasma HIV viral loads decreases the risk of viral transmission significantly. I'll reprint some information below about this topic from the archives. You can read much more if you search the archives and related links.

Finally, you should never be concerned about leveling with your doctor. He's on your side. He's there to help you, not pass judgment on indiscretions!

Good luck.

Dr. Bob

poz to poz sex,guy prefers no condoms (POZ ON POZ BAREBACK) Jun 11, 2008

I recently had sex w/a person and when we started,I exposed my status.I was surprised when he also is Poz and he enjoys the sensation of me depositing my load in him.Sounds great to me-I like to implant my seed,so is there really a problem w/this.I searched for an answer,yet didn't see anything + or - about this.

Response from Dr. Frascino


You searched for an answer and didn't find anything about this topic? Hmm . . . I don't think you searched all that hard! See below.

Dr. Bob

Positives with Positives- their risk of going bare- any studies? Apr 11, 2008

Hawaii says aloha from someone who knew you down in the South Bay years back.

I don't know how prevalent this notion is nationwide, but on this island it seems the prevailing attitude is (with a huge dose of wishfull thinking and condom fatigue)that positives having sex with each other can now fuck without comdoms, that the HIV risk is low. It is the prevailing behavior I fear and I am not sure how to defend against it. I'm wondering if there are any definative studies or even if such a study is possbile. I'm hearing answers all over the map- that one can't catch someone elses virus, that undectables can't be reinfected, to- one can catch a multi drug resistant strain even if undectable. The positive community seems distrustful of the prevention community because they will "tow the line" and say what they are told to say. Is there solid eveidence to base these crucial desisions on. This is from one who went through hell and came back to life and is 12 years out undectable. I am becoming sexually active after a long absense and feel a bit like I did back in the 80's, dazed and confused. What can I know for sure with so many variables,let alone alllll the other STD's from which I was spared?

Response from Dr. Frascino


From the South San Francisco Bay Area to Hawaii??? Nice! Certainly beats moving to Fargo or Crawford! If you continue on your current trajectory you should next wind up in Fiji or perhaps Sydney, both of which are also excellent habitations!!

The poz-on-poz story is indeed somewhat confusing and complicated, as you stated, by everything from condom fatigue to wishful thinking to anecdotal stories. So here are a few realities that might help:

  1. For poz-on-poz, neg-on-neg or any combination in between, unsafe sex places both individuals at risk for a wide array of STDs. STDs can behave differently in folks with HIV (or compromised immune systems from any other cause as well). Hepatitis, syphilis, HPV and many others can have far more serious consequences for HIVers than for those with intact immune systems. This fact alone should be enough to convince HIVers that unsafe sex isn't worth the risk.

  2. Dual infection (superinfection, reinfection) is indeed possible and has been well documented scientifically. What we don't know is exactly how frequently this actually occurs. It appears to happen more frequently in early infection. I'll report below some information about dual infections.

  3. The "undetectable can't be reinfected" story may stem form the "Swiss Report." This report suggested that under specific circumstances (HIV plasma viral load suppressed to undetectable levels for greater than six months without concurrent STDs) HIVers would not transmit the virus to HIV-negative partners. This story was highly criticized, as it was merely observations drawn form looking at the results of select previously published studies. The subjects mainly include heterosexual couples, etc. Consequently extrapolating this concept to state that undetectable HIVers are not infectious is premature, to say the least. What we can with considerable confidence report is that HIVers with undetectable plasma HIV viral loads are significantly less likely to transmit the virus to their partner (neg or poz).

Hope that helps! Enjoy I have already responded to one of those fancy cocktails served in a pineapple with the little umbrella sticking for me, OK?


Dr. Bob

poz to poz barebacking risky? Feb 4, 2008

Hi Dr. Bob, I became virally enhanced in 2007 and I'm still trying to adjust to the reality of it. My questions relate to barebacking between 2 poz guys. My doctor has warned me to always always use condoms now to prevent superinfection with a different strain and to prevent transmission of resistance. But when I chat with other poz men or read their online profiles I can't find any poz men who use condoms with other poz men. Is the risk of superinfection and resistance real? If my partner and I bareback(we both show no resistance on tests)are we still risking our health? Is a top less likely to obtain resistance or superinfection from a bottom? I'm just confused by this because I want to do the right thing and follow my doctor's advice but I'm beginning to think that very few poz men use condoms if their partner is also poz. I would appreciate your insight. Thank you.

Response from Dr. Frascino

Hi Poz Newbie,

You can't find any poz men who use condoms with other poz men online? Hmm . . . dude, you need to change chat rooms.

"Is the risk of superinfection and resistance real?" Yes, it is. (See below.) What we don't know is exactly how often it actually occurs. It seems to happen more during early infection. This may correlate well with the evolving data on decreased infectivity seen in the face of an effective antiretroviral regimen and fully suppressed (undetectable) HIV plasma viral load. (See below.)

If you and your partner decide to go commando Rambo on each other's backside, are you risking your health? Yes, all unprotected penetrative sex presents some degree of risk for not only HIV dual infection, but also for other STDs.

As for top versus bottom, the receptive (bottom) partner is always at greater risk for acquiring an infection.

Dr. Bob


I was recently diagnosed with HIV last week so I am still learning more and more every day. I know that it is early but I would like to get a head start to prolong my life. I have been with my boyfriend for two years; he was the one that infected me. I still plan on being with him since he did not give HIV to me on purpose. We currently do not use condoms since we are in a monogamous relationship. Since we are both HIV+ we figure that we can still go "bareback." I have been reading material on this thing called a superinfection when you can get infected with another strain of HIV.

My question is: Since he gave me HIV, we both have the same strain, can we continue to go "bareback?" Will this change once we start on different med regimens? PLEASE HELP.

Response from Dr. Frascino


This question comes up frequently. (See below.) At this point, what we know is that superinfection can and does occur, but we do not know how frequently it actually happens. It appears to be more common early in the course of infection. Our advice at this point is to use condoms even in poz-poz relationship. The information below explains the rationale for our recommendation.

Good luck. Stay well.

Dr. Bob


I was infected in June07, having been a public dump at a $4 theater already for months. The same 5-10 men are using me weekly, another 10 a month are new, & another 3-4 a month are negative people wanting to have sex with me, which I have took advantage of. My CD4 was849 in july now 526(26%) , viral load was 152,000 now 80,030.I am not scheduled for labs till end of Jan. At the present rate I will have aids by then. I'm new at this. Am I superinfected?

Response from Dr. Frascino


Sorry to hear about your recent diagnosis. I would suggest, because this is indeed "new" for you, that you get informed about HIV, HIV-monitoring tests, HIV treatments and HIV transmission. A good place to start is to read through the information under the "Quick Links" heading on The Body's homepage. There you will find chapters on "Just Diagnosed," "HIV Monitoring Tests," "HIV Medications," etc.

Regarding superinfections, I'll repost some information about this from the archives. The way to prevent superinfection (and a variety of STDs) is to properly use latex condoms for penetrative sex.

As for your fear that you'll have AIDS by the end of January, I would seriously tend to doubt this. However, you do need to begin protecting yourself and your partners. Please note you are legally required in most states to disclose your HIV status before having sex with them.

Also it might be helpful for you to know I've been HIV infected since January 1991 and I'm still here. A long and satisfying life with HIV is indeed possible, but you'll need to get informed and begin taking responsibility for your health.

Good luck.

Dr. Bob

couple with AIDS Nov 4, 2007

Thank you Dr. Bob for your reply. Yes, we are seeing a very good doctor. But we had to go through a lot of doctors and tests to find out what was wrong with us. My boyfriend and I do plan on using condoms from now on. But I guess I was just wondering how it already affected us up till now. We were probably still both just HIV status before we met, but we are in our 40s and did not use protection. We both started getting sick fast about a year ago. Do you think that we caused each other to drop faster?

Response from Dr. Frascino


I have no way of knowing, in fact, over the Internet whether you and your partner actually did acquire each other's viral strain and if so whether that dual infection resulted in further more rapid progression of your illnesses. In any case, life only moves in one direction forward. Stop worrying about the past and focus on the realities of today and the promise of tomorrow, OK? I'm glad you are both now under the care of a competent HIV specialist.

Good luck to you both!

Dr. Bob

couple has AIDS Nov 2, 2007

Dr. Bob, My boyfriend and I both were diagnosed with AIDS this past August. His t-cell count was 89 and mine was 6. We have only been together for 2 years. I just moved back to this state 3 years ago. Before we met, we were both married. It seems unreal that we both had HIV before meeting each other, and that we had it for probably the same length of time. What will it do if we have unprotected sex now?

Response from Dr. Frascino


Another two married dudes (who certainly never should have been married in the first place) who had longstanding HIV/AIDS infections and you didn't know it until this past August???? Hmmm . . . here we have additional evidence once again that our HIV/AIDS awareness and prevention programs in the U.S. are an abysmal failure!!! It's frustrating, disconcerting and sad that over 25 years into the pandemic with over 25 million lives snuffed out by the virus, stories like yours are still so prevalent.

Now getting off my soapbox, I'll move on to your question. You both have advanced-stage AIDS. If you decide to have unprotected sex, you run the risk of contracting a superinfection. In other words, you could each contract the other's strain of virus. This theoretically could make your HIV disease progress faster or become more difficult to treat. For instance, if you or your partner picks up a strain that is resistant to one or more of the medications in your regimen, this could have disastrous consequences. Exactly how often superinfection (dual infection) occurs, we don't know. What we do know is that it is possible. You can read about dual infection or superinfection in the archives. Personally, this is definitely not a risk I would take.

I trust you are both under the care of a competent AIDS specialist physician. If not, you should be!

Good luck to you both. I'm here if you need me, OK?

Dr. Bob

serosorting & unprotected sex between 2 hiv + men (SUPERINFECTION) (DUAL INFECTION) (CO_INFECTION) (REINFECTION) Sep 28, 2007

my boyfriend and i (we are gay males) have been dating for a while. we met after we were both diagnosed with hiv. we prefer anal sex without condoms - what is the most recent data and information on reinfection? we are on different hiv anitretroviral medication. both our viral loads are undectable and our t cell counts are 400-500 range.

Response from Dr. Frascino

Hello Poz-Guys,

No doubt almost everyone poz or neggie would "prefer" sex (anal, vaginal, oral or otherwise) without the latex packaging. The real question is whether it's worth the risk! What we know about dual infection (reinfection or superinfection) is that it can indeed occur and that it can have catastrophic consequences. What we have learned more recently is that this unfortunate and completely avoidable situation occurs less frequently than we originally feared. Recent data indicate it occurs most readily in cases of recent HIV infection. Collecting data on reinfection cases is difficult and performing controlled clinical trials would be unethical. Consequently the best we can do is collect anecdotal and epidemiological data. Only you and your partner can decide if the risk is worth the pleasure. Also "no-glove love" leaves you both open to all other STDs as well. Any STD may have the secondary effect of increasing HIV replication and plasma viral load, which, in turn, could increase your risk for developing resistance to HIV medications. I'll reprint some information about dual infection from the archives below. Based on what we now know, the recommendation for safer sex (condoms), even between two poz partners, remains unchanged. The risk you and your partner are taking is not one I would personally accept.

Good luck to you both, whatever you decide.

Dr. Bob

raw meat! (SUPERINFECTION) (COINFECTION) Mar 17, 2007

I am poz and so is my partner. He insists on barebacking me. I argue with him but I always end up taking his load. Is this going to make me die sooner? What effect will having a big load dumped in me almost every day do to my health? I am on meds am undetectable and my partner is also undetectable. does this make a difference? Also I am on a P.I. and he has never been on one. Oh yeah, he shoots an exceptionally big load...does that mean more hiv per load?

please help!

Response from Dr. Frascino


Even poz-on-poz barebacking is risky business. Will it make you die sooner or have a deleterious effect on your health? Theoretically it could, if you were to become coinfected with a more aggressive strain of HIV. That your partner has an undetectable plasma viral load (at least as of his last blood draw) would decrease, but not eliminate, the risk of HIV transmission. I'll reprint some information below from the archives that discusses coinfection/superinfection. Finally, I should point out while your partner may "insist on barebacking," it takes two to do the commando unsafe mattress mambo!

You have the power to insist "no glove, no love, no exceptions!"

Dr. Bob

hiv and sex (SUPERINFECTION) Jan 12, 2007

Both my partner and myself are hiv +. He contracted hiv from me. We have been totally monomagous in our relationship since meeting over 16 months ago, me getting hiv from another person prior to meeting him. I am on both truvada and sustiva at this time. As of last week my viral count is undetectable, and my cd4 count has now climbed back up to the 640's, was in the low 400's earlier. My partner is not on meds at this time and his viral count is still detectable and his latest cd4 count was in the 400's. I have problems maintaining an erection with condoms, which is what got me and him in this condition to begin with. Although we tried to be "safe", things failed. I love him very much as he does me. Question is, Are there risks if we were to start back with totally unprotected sex between us, with both of us now hiv + and knowing for sure that he contracted hiv from me? Are there risks of creating more problems, specially since I am on meds at this time and he is not.

Response from Dr. Frascino


Yes, the risk of superinfection is indeed real, even though we do not know now often it occurs. (See below.) If you are having difficulty maintaining your erections, talk to your HIV doctor. Erectile dysfunction is quite common in HIV+ men. Viagra or Cialis may be worth a try.

Good luck.

Dr. Bob

Serosorting vs Superinfection Jul 23, 2006

Hi Rob,

first of all i really love your way of handling questions and answering them. It brings some humour to it all, which i feel is more than necessary.

I'm HIV+ for 4 months, diagnosed right in the middle of seroconversion period, probably infected end of february. Current numbers : april: CD4:400, VL:180000, may : CD:480 - VL:1530 (will get new numbers in 14 days) I do have 2 questions :

Q1: 1 month ago, I met 2 guys in our local support center. We ended up having sex - unprotected, which of course was a foolish thing to do and it was the first time i ever did it, no excuses there besides maybe being angry with myself. Anyway: i know one is taking medication (first regime) is said to be "fast progressing", the other one is poz but undetectable - no meds. I've been reading about possible superinfections in several articles, and on the other hand reading about serosorting and the ability of poz men having sex with poz men without much risk. I'm however pretty worried about having a possible superinfection. My question is : how severe is this risk of superinfection and should i even consider serosorting ? (i know about the risk of other SOA's but the risk there is very clear).

Q2: This question is related to Q1: My meds specialist, as an introduction to ever needing meds, informed me about the risk of becoming immune due to receiving parts of the medications given by the other guy through the semen while being infected. It would be a possible i may have built up some resistance without even taking any meds. I'm afraid the same happened now with my latest endouver, knowing one of them was on a first regime meds. How real is this threat ? Should i really be worried ? Should I talk about it with my hiv specialist ?

Thx ahead, you're support is really appreciated !


Response from Dr. Frascino

Hey Bert,

Q1) Superinfection is indeed a real risk for poz-on-poz barebacking. I've addressed this topic and serosorting many times in this forum, so I'll just repost a few questions from the archives and encourage you to search the archives for additional information if you so desire.

Q2) Developing resistance to HIV drugs is not the result of "receiving parts of medications given by the other guy through the semen." Perhaps something must have gotten lost in translation as your specialist was trying to explain the phenomenon of acquired resistance to you. What really happens is that an infected person can become superinfected or dually infected with strains of HIV that have developed resistance to one or more anti-HIV medications. This, too, is discussed in the archival posts below.

My advice remains to stay safe.

Dr. Bob

POZ with POZ

Jul 18, 2006

I am a healthy POZ sexually active gay man, generally a bottom. I have always been of the opinion that condoms are a good idea, period. They reduce the chance of more than just HIV. But lately I have frequently heard POZ guys saying that they bareback with other POZ guys because everyone is getting treated and doing so well. Comment please.

Response from Dr. Frascino

Hello Poz Guy,

I agree with your rational and would extend it somewhat. Condoms protect against a host of nasty STDs, many of which are on the upswing among men having sex with men. An active STD can indirectly cause your HIV viral load to skyrocket. As viral replication goes up, so does the chance that the virus may mutate into a form that may be resistant to one or more of the medications in your current regimen.

Next, the possibility of a dual infection or superinfection is real. Although, we do not know how often this actually occurs, we do know that it can occur. Is that a risk you're willing to take? It's one I certainly would not. I'll repost a few questions from the archives that give further details on this topic.

Stay safe. Stay well. Be here for the cure.

Dr. Bob

Is safe sex necessary if both partners are + Dec 28, 2005

My husband and I are both positive and I was infected by him. Our Dr. says we must have safe sex or we can make each other sick. Is this true? It seams weird. Also I saw people were having trouble getting insurance after that were diagnosed +. I work for Anthem and they cover pre-exhisting conditions like HIV. I had no problem adding my husband to my policy, even thought he had been positive for over 6 years.

Response from Dr. Frascino:


Your doctor is cautioning you against the possibility of superinfection or reinfection. Even if you were initially infected by the same strain of HIV, the virus can evolve differently in each person. Consequently, over time your virus may be quite different from your husband's. I'll post several articles and a question from the archives that address this topic. I hope you'll consider this information carefully. Stay well.

Dr. Bob

How safe does HIV+ couple have to be? Aug 26, 2004

Dr. Bob,

You inspire and console many, and are appreciated by the positives and negatives in this fight.

Ok, here is my question, I have been dating another HIV+ man for over a year and we have entered a committed relationship. We are both in our 50's and look forward to a great long life together. Both of us are on a drug regiment and have undetectable viral loads. We both have a good T-cell count and both of us are very healthy. If we live in a committed and monogamous lifestyle, how dangerous would un-protected sex be if we both have the HIV virus already, and are both compliant on our drug regiments?

We are very happy with our current safe sex practices, but are curious what you would say to this question.

P.S. Our doctors are evasive, first telling us about the risks of super infection, but then eluding to the fact that it would be unlikely.

Thanks! Curious in Boston

Response from Dr. Frascino

Hello Curious Boston Boys,

Actually your doctors are right on target. There is indeed a risk of superinfection. Cases of superinfection have now been well documented. The question of how often it occurs remains unanswered. That might explain your doctor's seemingly "evasive" comments. In reality we don't have a lot of information about the frequency of HIV super-infection because it's not all that easy to document without rather extensive and costly analysis. Certainly the major concern is the acquisition of a more virulent (aggressive) strain of HIV, or one that is resistant to some of the drugs in your current regimen.

As two consenting adults, only you and your partner can decide if you are willing to take this risk. You mention you are "very happy with your current safe sex practices." All I can do is advise you that the risk of superinfection is real, very significant, and potentially devastating. Even though the chance of HIV transmission is decreased by having undetectable viral loads, HIV superinfection is not a risk I would not be willing to take personally. Good luck, Boys. There may be some more information on this topic presented at an HIV/AIDS medical meeting in your hometown scheduled for February 2005. Stay posted to this site and I'll keep you posted as well!

Dr. Bob

Re-Infection: Is It a Concern for People Living With HIV? May 2004 Re-infection is a term used to describe a new or secondary infection by a virus that has already infected a person. In most viral diseases, re-infection with the same virus doesn't occur because once the immune system conquers the original viral infection, it creates immunity against that virus. Re-infection occurs almost constantly, however, in some types of infection, such as the cold or flu viruses, because each new version of those new viruses is substantially different from the last. This is why a person may develop immunity to the flu strain that is common in one year, but still be at risk from the strain that becomes dominant the next year.

The question of re-infection with HIV has long been debated. There is no theoretical reason to think re-infection isn't possible, since the immune system never fully conquers the initial HIV infection. Still, many people, including many physicians, clung to the hope that re-infection with HIV either does not happen or that it only happens rarely. This view is the basis of the belief held by some HIV-positive people that having sex or sharing needles with another HIV-infected person poses little or no risks. Many if not most virologists, however, have long believed that re-infection is both possible and perhaps even likely. What is not known are the individual short- and long-term clinical consequences (which may vary from person to person for wholly unknown reasons). For many years, there were no clear cases of re-infection presented at scientific conferences, but this did not mean such re-infection wasn't occurring. Instead, we know that finding and documenting cases of re-infection is extraordinarily difficult, if for no other reason than that no structured program has looked for them. Finding a case of re-infection has largely been a matter of chance. Yet, several observations over the years support the notion that re-infection is possible, including observations of sex workers in Africa infected with several different recombined "clades" of HIV as well as detailed genetic analysis of a few people's virus suggesting that re-infection was possible. This research is very difficult to conduct. Perhaps the only simple example of re-infection is in western Africa, where people are routinely found who carry both HIV-1 and HIV-2. At the very least, this proves that having HIV