Evaluation of the prevention of mother-to-child transmission of HIV program in Zambia.

Between October 2014 and May 2016 HIVCore conducted a cohort study among 653 HIV-positive pregnant women receiving antenatal care (ANC) in the northern provinces of Central Copperbelt and Luapula provinces. Study staff conducted follow-up surveys at 6 weeks 14 weeks and 9 months following delivery collecting self-reported information on PMTCT service utilization and behaviors including maternal antiretroviral therapy (ART) infant feeding and infant ART and cotrimoxazole use. In addition at the same three time points we administered polymerase chain reaction (PCR) infant testing of participants’ babies allowing us to estimate cumulative mother-to-child transmission (MTCT) rates at each point in time. Follow-up interviews and infant testing were conducted in conjunction with routine vaccinations (diphtheria pertussis and tetanus vaccine at 6 weeks [DPT 1] DPT 3 at 14 weeks and measles at 9 months). The authors conducted descriptive and bivariate analyses to examine and compare outcomes of interest at each follow-up period overall and across districts. To estimate MTCT rates we utilized a life table technique that accounted for infant seroconversions withdrawal death and loss to follow-up over time. Out of the 653 enrolled women 667 infants were born whom we sought to observe in subsequent follow-up periods. Of those infants 516 infants (77 percent) were retained in the study through the 9-month interview. Of these 503 received PCR test results.Overall PMTCT service utilization and behaviors were high: 1) 93 percent of participants delivered in a facility; 2) 99 percent of women were currently on ART at 9 months; 3) The proportion of infants ever receiving ARV prophylaxis (reported by mother) increased from 66 percent (6 weeks) to 92 percent (9 months); 4) The proportion of infants currently taking cotrimoxazole increased from 87 percent (6 weeks) to 99 percent (9 months); and 5) 62 percent of infants were exclusively breastfed at 6 weeks after birth 40 percent at 14 weeks and 9 percent at 9 months. The overall cumulative 9-month MTCT rate was 2.3 percent ranging from 1.0 percent in Ndola to 3.4 percent in Nchelenge. This MTCT rate was notably lower than the previously documented estimate of 13 percent. Among women who initiate and are retained in PMTCT care at study facilities the program is quite successful at minimizing vertical transmission. Nevertheless generalizability of these findings to the broader community of HIV-positive pregnant women should be made with caution. Study participants likely had better service access and utilization compared to the broader population; they were women already seeking facility-based ANC who already knew their HIV status. Furthermore since study staff enlisted local community health workers to proactively follow up with participants and encourage retention in care the women in our sample benefited from outreach efforts that the general population would not have. (excerpt)