The story of a Boston man living with HIV became a revelation at last week’s International AIDS Confer-ence in Barcelona, after scientists searching for an HIV prevention vaccine were told the man had become super infected.
The patient, known by his research code as AC06, was showing promising results as part of an American vaccine trial. His immune system had mounted a robust attack against HIV and had suppressed the virus completely for several months without antiretroviral treatment.
However, AC06 then had unprotected sex and contracted a second, different strain of HIV virus. Even though his immune system was controlling the original HIV strain, it was unable to control the second strain, which is now running uncontrolled in his body.
According to a report in The Wall Street Journal, scientists had debated whether it was possible for super infection (reinfection on top of an existing infection) to occur with HIV. Many HIV-positive people believed that because they were already infected, no further harm could come from unprotected sex with another HIV-positive person.
The case study was seen as a major set-back for the future discovery of an effective HIV vaccine, with the chance of patients contracting a different strain of the virus to that covered by a given vaccine now believed to be a bigger risk than anticipated.
The discovery is also grim because it shows that a person can get infected with a drug-resistant strain that could undermine drug therapy.