Most new HIV infections amongst gay men in Switzerland originated in individuals with chronic HIV infection, investigators report in the online edition of AIDS.
Transmission clusters were mapped amongst gay men recently infected with HIV in Zurich and in the Swiss HIV Cohort. Only two infections appeared to originate from individuals with very recent HIV infection. In all other cases, the source patient was an individual who had been infected with HIV for at least one year.
“Infectiousness during chronic infection was quite high in this population”, comment the investigators.
None of the individuals transmitting HIV was taking antiretroviral therapy and had an undetectable viral load.
The investigators believe that their findings support “early” and “continuous” use of HIV treatment by gay men, and suggest that this could profoundly slow the HIV epidemic in this population.