Chronic HIV-1 Infection Frequently Fails To Protect Against Superinfection

Superinfection of HIV-1 occurs when an individual infected with one strain of HIV-1 acquires a second strain. Currently there are over 20 published cases of HIV-1 superinfection, most of which have been focused on individuals who have been carefully monitored during their infection. These cases prove that an HIV-1 vaccine may not always protect against infection by a different strain. But because there have been reports of selected individuals, it has been unclear how commonly HIV-1 re-infection occurs.

To address this question, Dr. Julie Overbaugh and her research team investigated the incidence of HIV-1 superinfection in 36 high-risk women followed roughly five years after their initial infection.

Seven cases of superinfection were found; five of them occurring over a year past initial infection. Additionally, three of the seven cases displayed a virus from the same HIV-1 genetic subtype.

This study suggests that immune responses found in natural HIV-1 infection, which fail to provide protection against re-infection, may not be the best path to an effective HIV-1 vaccine.