The HVTN’s Step study, a large phase IIB trial of a candidate HIV vaccine which included pieces of the virus adenovirus 5 (Ad5), surprisingly showed that uncircumcised men who had been infected with Ad5 in the past and received the candidate vaccine were more likely to become infected with HIV than those who received the placebo in the trial. The reason for this unexpected increase in infections is unclear, but some researchers wondered whether pre-existing infection with Ad5 could be a risk factor for HIV infection.
To test this possible connection, former VIDD staff physician Dr. Marcel Curlin and colleagues, including VIDD associate member Dr. Amalia Magaret, member Dr. Ann Duerr and Center President and Director Dr. Larry Corey, staff scientist Dr. Greg Spies, and co-director Dr. Julie McElrath, looked at whether prior Ad5 infection was more common among HIV-infected people than HIV negative people. They looked at volunteers from two large AIDS-related trials, the Multicenter AIDS Cohort Study and the HIV Prevention Trials Network 039 trial, and asked whether the 299 individuals who acquired HIV infection during the trials were more like to have pre-existing antibodies to Ad5, indicating past Ad5 infection, than those who did not acquire HIV. They found no difference in Ad5 infection rates in the two groups, nor did the levels of Ad5 antibodies in the people’s blood correlate with HIV infection, indicating that Ad5 infection alone does not increase the risk of HIV infection.
Curlin ME, Cassis-Ghavami F, Magaret AS, Spies GA, Duerr A, Celum CL, Sanchez JL, Margolick JB, Detels R, McElrath MJ, Corey L. Serological immunity to adenovirus serotype 5 is not associated with risk of HIV infection: a case-control study. AIDS. 2011 Jan 14;25(2):153-8.