In recent years, medical science has made great progress in our ability to successfully treat HIV infection and associated opportunistic infections (OIs). Wider use of medications for preventing tuberculosis, Pneumocystis carinii
pneumonia (PCP), toxoplasmosis, and Mycobacterium avium
complex (MAC), for example, has helped reduce the number of people with HIV who develop serious illness and die from AIDS. Also, several new compounds in a new class of drugs, called protease inhibitors, have been federally approved to treat HIV infection. These drugs, when taken in combination with previously approved drugs such as zidovudine (ZDV, also called AZT), lamivudine (3TC) and dideoxyinosine (ddI), reduce the level of HIV particles circulating in the blood (viral load) to very low levels in many individuals. Treatment results using these drugs have been extremely encouraging, as these drug combinations are more effective than any previously available therapies. Researchers are hopeful that this type of combination therapy, with further study, will prove effective long-term and increase the healthy life span of more HIV-infected individuals.
Is it time to declare victory over HIV and AIDS?
Not yet, as there remain several areas of uncertainty and reasons for caution. Even though an estimated two-thirds of all HIV-infected people in the United States have been tested and know their serostatus, many remain unaware of their HIV infection until they are diagnosed with an AIDS-associated illness. People need to know they are infected so they can take steps to protect their health and prevent the transmission of HIV to others. People who learn their HIV serostatus early in the course of infection can benefit from taking medications specifically to prevent OIs, as well as other drugs to suppress HIV in their bodies.
Another significant concern is the effect that knowledge about success of the new
combination therapies will have on prevention efforts. It is critical that individuals at risk do not relax their preventive behaviors because of the availability of more effective treatments. It is also important for prevention services to reach the increasing numbers of people living with HIV and help them maintain safer behaviors.
AdvertisementWhat is the long-term effectiveness and safety of these new combination therapies?
Most patients have been studied for less than 2-3 years. Because these drugs are so new, their long-term effectiveness and safety are still unknown. What we do know is that --
- the new combination therapies reduce the concentration of HIV circulating in the
blood of most individuals, but there is no evidence that the therapies completely eradicate the virus from all parts of the body. It is not known how long these drugs
will be effective in maintaining reduced levels of HIV in the bloodstream. HIV may rebound from such areas as the lymph nodes, brain, or white blood cells.
- these drugs do not work for all people with HIV infection. In some individuals, substantial levels of circulating virus persist despite use of the newer drug combinations.
- many patients develop serious side effects which prevent them from continuing to take the drugs. Moreover, the long-term health consequences of taking these drugs
for many years are unknown.
- these drugs are extremely expensive ($12,000 or more per year for the drugs alone), and paying for the drugs is a challenge for many people.
- because of the high costs, these therapies are not widely available in developing countries where over 90% of new HIV infections are occurring. Fighting the epidemic globally will require more cost-effective solutions.
- these drugs will be added to the long list of drugs taken by people with HIV
infection, and they sometimes have adverse interactions with other medications. In
particular, there are serious problems with taking protease inhibitors in conjunction
with drugs commonly used to treat TB. Physicians prescribing these drugs must
carefully consider all potential interactions.
Can HIV develop resistance to the new drugs?
Yes. The new combination therapies require patients to follow complex treatment
regimens, taking multiple medications several times each day. Some must be taken
with food, and some must be taken on an empty stomach - and these drugs may have
to be taken for the rest of the patient's life.
People who miss doses of their medication may be at increased risk for developing
drug-resistant strains of HIV. If these strains are transmitted to others and spread
widely, HIV infection could become much more difficult to treat.
Do these new drug therapies block transmission of HIV?
While studies are being conducted to investigate how new drug therapies relate to
infectivity, conclusive findings are not yet available about their protection against HIV transmission. As we learn more about the impact of new combination therapies on
infectiousness, it is possible that our treatment and prevention strategies will become more closely intertwined. In the meantime, it is critical that people adopt or maintain protective behaviors that are known to be effective in preventing the spread of HIV infection.
How has information about these new drugs affected behavior in at-risk populations?
Research suggests that some individuals are less concerned about becoming infected
than in the past and may be inclined to take more risks. Moreover, some may assume
that HIV-positive individuals taking protease inhibitors are not infectious. As a result, some people may believe there is no longer a need to avoid high-risk sex and drug use. CDC is concerned that people may be placing themselves at unnecessary risk because of these assumptions. Another concern, as mentioned above, is the transmission of resistant strains, which could undermine the benefits of treatment advances.
Are the new drug therapies the key to controlling the HIV/AIDS epidemic?
A wide range of behavioral and biomedical strategies are needed to control the
epidemic. No medical advance, by itself, can succeed unless it is accompanied by
appropriate behavior change. Even a vaccine does not stop a disease unless it is
available and people have access to it. As researchers continue working to develop
better treatment and prevention options, we must continue to focus on preventing HIV
infection, which precludes the need for people to undergo complex, costly treatment
regimens. A strong foundation of behavioral interventions must be maintained and, at
the same time, there must be a focus on developing and strengthening biomedical
prevention interventions such as vaccines, microbicides, and the treatment of other
How can care, treatment, and prevention work better together?
Better integrating care and treatment services, including those for STD and substance abuse, would allow us to take advantage of multiple opportunities for prevention -- first, to help the uninfected stay that way; second, to help infected people stay healthier; and third, to help those who are infected initiate and sustain behaviors that will keep themselves safe and prevent transmission to others.
In some cases, treatment is prevention. When pregnant women and their newborns are treated with ZDV, for example, the chances of mother-to-infant HIV transmission are greatly reduced. We also know that treating other STDs can greatly reduce the risk of transmitting or acquiring HIV infection. Substance abuse treatment that succeeds in getting a drug user to stop using drugs can prevent his or her own infection through sharing needles, as well as possible future HIV transmission to sex partners.
Reaching the HIV-Infected
Among those who are infected, using new drug combination therapies to suppress the virus and medications that we know are effective in preventing the development of opportunistic illnesses will keep people healthier longer. Also, prevention case management services have proven effective in helping people with HIV adopt and sustain safer behaviors. With HIV-infected persons living longer and healthier lives, prevention will be even more important. Ongoing services for people who are HIV positive must balance medical advances with the behavioral and social support needed to preserve their quality of life and prevent the spread of infection.