Immunotherapies to Prevent Mother-to-Child Transmission of HIV

Although pharmacological interventions have been successful in reducing prevention of maternal to child transmission (PMTCT) of HIV, there is concern that complete elimination through this mode of transmission will require other measures. Immunotherapies in infants or pregnant mothers may be able to eradicate this form of transmission. A recent vaccine trial in adults showed encouraging results, but as in most HIV safety and efficacy vaccine trials, the question of MTCT was not addressed. Concentrating transmission studies and vaccine studies in the setting of MTCT offers several advantages. MTCT has a generally reproducible known transmission rate and has been successfully used to assess pharmacological interventions on decreasing transmission. Even in resource poor settings, the infrastructure for neonatal vaccination is already in place. Although rare, both passive and active vaccination trials have been successfully completed in pediatric populations. Unfortunately, little success in affecting MTCT has been shown. Largely, a correlate of protection in any type of transmission, including MTCT, is unknown. Data supports a role for antibodies in effecting strain and transmission during MTCT. The role of antibodies in MTCT is reviewed with a focus on recent passive immunization and considerations for future studies.