Scientists Document Increasing Reports of HIV Superinfection
Associated Press
Emma Ross
July 15, 2003
Growing evidence indicates that "superinfection" with more than one strain of HIV might be more common than previously thought, possibly complicating vaccine efforts, according to experts at the International AIDS Society Conference on HIV Pathogenesis and Treatment in Paris. On Monday, scientists reported three new cases of HIV- infected people who initially were doing well without drugs but became sick years later after contracting a second strain of HIV.
"Superinfection is sobering," said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, who was not involved in the studies. "That means that although you can mount an adequate response against one virus, the body still does not have the capability to protect you against new infection, which tells you that the development of a vaccine is going to be even more of a challenge," Fauci explained. Though it is too early to tell how big a problem superinfection will become, Fauci said he does not believe superinfections are the reason patients on treatment can suddenly deteriorate.
None of the patients discussed at the conference was being treated for HIV, which can become resistant to drugs over time.
At the meeting, Dr. Luc Perrin, professor of clinical virology at the University of Geneva, reported is covering superinfections in two Swiss IV drug users. In the study, Perrin followed 136 HIV-infected drug users and found that the amount of virus in the blood of five patients suddenly escalated after years of control without drugs. Testing confirmed that two of the five had a superinfection, said Perrin.
Another study by Dr. Harold Burger, of Albany Medical College in Albany, N.Y., reported genetic tests on a superinfected woman showed the two viruses mixed and produced a hybrid that took over from the original virus. It is the first documented case of two HIV strains, or subtypes, combining in one person to form a third strain - something scientists have suspected could occur. "We just don't know how common it is. People say it's rare but we just don't know," said Dr. Anton Pozniak, an AIDS specialist at Chelsea and Westminster Hospital in London, who was not connected with the research.
"The issue is can you get a vaccine that will cover all subtypes?" said Pozniak. "This reinforces the message that we've got to stop HIV today so that we can deal with what we have now and not generate a whole load of new mutants that wouldn't have been there otherwise," Pozniak said.