For example, some study in order to identify the risk of HIV-1 infection in RV144, two sequential sets of analyses of plasma specimens shown that the levels of IgG antibodies (Abs) specific for gp120 V2 were correlated with decreased the risk of infection, the level of IgA Abs reactive with envelope glycoproteins correlated with decreased vaccine efficacy [12]. Here, ERVW-1 is linked to infection.