ERVW-1 and infection: In a suggestive parallel to the Vax004 result, Env expressed from a replicating adenovirus-5 vector did not protect macaques against multiple low-dose SIVmac251 rectal challenges; but the infection rate in the Env-vaccine group was significantly lower for animals with high levels of Env-specific sIgA antibodies in rectal secretions than for those with low levels [43].