Barebacking may lead to re-infection - TheBody.com's Bulletin Boards

‘Super-infection’ may slow development of AIDS vaccine
Barebacking may lead to re-infection, multiple strains of disease, researchers discover

ATLANTA -- The ability of HIV to develop multiple strains has ignited concerns among some AIDS researchers about a "super-infection" that may threaten the success of vaccines designed to stymie the disease and adds to safety concerns over barebacking.

A case study presented earlier this month at the XIV International AIDS Conference in Barcelona highlighted the case of a Boston man who was already reacting well to vaccine trials for one strain of HIV. But he barebacked -- anal sex between two men without using a condom -- with his HIV-positive partner and acquired a second strain, creating what researchers call a "super-infection."

The study demonstrates the difficulty in reaching a viable vaccine as various subtypes and strains of HIV work in tandem to negate a vaccine's effects, according to Bruce Walker, the Harvard Medical School doctor who presented the case study.

"HIV is not really one disease," Walker said. "The opportunity to contract a second or even third strain is very high."

While Walker and other vaccine researchers warn that more studies should be done, they also say the Boston case study dispels a misconception among some gay men that HIV-positive partners can have unsafe sex without fear of re-infecting each other.

And although the study is of just one patient, it provides great detail because Harvard researchers collected blood samples and laboratory tests for a separate study on the Boston patient for more than a year before he acquired the second strain, Walker said.

"The detail available on this particular patient allowed us to conduct laboratory studies that make this a very solid study with measurable, reliable conclusions," he said.

Scientists have identified more than 10 subtypes of HIV, each of which contains "countless" strains, according to the Wall Street Journal. As HIV mutates in the body and is passed from one person to another, the divergent strains wreak havoc on what has been the predominant approach to vaccine research, the newspaper reported.

Researchers at Wyeth & Merck & Co., the National Institutes of Health, the International AIDS Vaccine Initiative, Yale University and the Emory Vaccine Center originally focused on vaccines that bolster T-cells to fight specific strains of HIV, but are already looking at tackling multiple strains, researchers said.

"The vaccine opportunities we are working on will necessarily fight varying strains of HIV," said Emilio Emini, research leader at Merck. "The test-tube research we presented at the conference shows we are already on that track."

Researchers at Emory in Atlanta are also reaching the same conclusion, said Rafi Ahmed, director of the Emory Vaccine Center.

"The case study just provides further validation that a vaccine should address the wide variety of HIV viruses," Ahmed said. "That may mean more than one vaccine for different variations."

Wake-up call for gays

For gay men, the study should immediately be a "wake-up call," said Gordon Mansergh, a gay scientist at the Centers for Disease Control & Prevention who led the first government study on barebacking.

"While we try to determine motivations for barebacking and gear prevention messages to break through the socio-cultural reasons men engage in risky behaviors, evidence is mounting that it is perhaps more important than ever to keep practicing safe sex, even if you're positive," Mansergh said.

But that message may be slow in reaching gay, HIV-positive men who bareback, according to Joseph Menendez, an HIV-positive San Francisco AIDS activist.

"I figured that once I was positive, that was it," Menendez said. "I mean, I already have HIV, so how could somebody give it to me again? That's why I bareback with other positives."

Gay men who bareback sometimes cite greater physical stimulation and a stronger sense of intimacy as reasons for their behavior.

But reaching those men with prevention campaigns is troublesome, said Eric Rofes, who wrote "Reviving the Tribe," a book about the struggle of gay men to stay focused as the epidemic wears on.

"Gay men are tired," Rofes said. "We've been dealing with this for 20 years, and especially HIV-positive men are looking for reasons to stop thinking about it and stop having to practice safe sex, even with our partners.

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