ERVW-1 and infection: Because the gp120 IgG binding responses in RV144 to vaccine-matched env glycoproteins (ie, A244 gp120 and 92TH023 gp120) were correlates of decreased infection risk,10 and the level of V1V2 antibody prevalence exceeded the threshold associated with 50% vaccine efficacy, these results offer cautious optimism for future efficacy of this regimen.