Surveillance of mother-to-child transmission prevention programmes at immunization clinics: the case for universal screening

BACKGROUND: Surveillance programmes for prevention of mother-to-child transmission of HIV (PMTCT) fail to quantify numbers of infant HIV infections averted, often because of poor postnatal follow-up. Additionally, infected infants are often not identified early and only gain access to comprehensive HIV care and treatment late in their disease.

METHODS: Anonymous, unlinked, HIV prevalence testing was conducted on dried blood spot (DBS) samples from all infants attending 6 week immunization clinics at seven primary health care clinics offering PMTCT. Samples were tested for HIV antibodies (indicating maternal HIV infection) and those determined to be from HIV-exposed infants were tested for HIV RNA by polymerase chain reaction. Infant and child mortality rates were determined using birth histories.

RESULTS: Samples were collected from 2489 infants aged 4-8 weeks. HIV antibodies were identified in 931 infants [37.4%; 95% confidence interval (CI), 35.4-39.4], of whom 188 were HIV RNA positive. The estimated vertical transmission rate (VTR) was 20.2% (95% CI, 17.8-23.1%); 7.5% of all infants at this age were infected. Amongst mothers who reported that they had taken single-dose nevirapine for PMTCT, VTR was 15.0%. Amongst women who reported being HIV uninfected but whose infants had HIV antibodies, VTR was 30.5%. Infant mortality rates in KwaZulu Natal increased from 28/1000 live births in 1990-1994 to 92/1000 in 2000-2004.

CONCLUSIONS: Anonymous HIV prevalence screening of all infants at immunization clinics is feasible to monitor the impact of PMTCT programmes on peripartum infection; linked screening could identify infected children early for referral into care and treatment programmes.