Child Transmission of HIV in Johannesburg, South Africa.

Prevention of Mother-To- Child Transmission

Effects of Highly Active Antiretroviral Therapy Duration and Regimen on Risk for Mother-to-Child Transmission of HIV in Johannesburg, South Africa.

Limited information exists about effects of different antiretroviral therapy regimens and duration of regimens on mother-to-child transmission of HIV among women in Africa who start treatment for advanced immunosuppression. Between January 2004 to August 2008, 1142 women were followed at antenatal antiretroviral clinics in Johannesburg. Predictors of mother-to-child transmission (positive infant HIV DNA polymerase chain reaction at 4-6 weeks) were assessed with multivariate logistic regression. Mean age was 30.2 years (SD = 5.0) and median baseline CD4 count was 161 cells per cubic millimeter (SD = 84.3). Antiretroviral therapy duration at time of delivery was a mean 10.7 weeks (SD = 7.4) for the 85% of women who initiated treatment during pregnancy and 93.4 weeks (SD = 37.7) for those who became pregnant on antiretroviral therapy. Overall mother-to-child transmission rate was 4.9% (43 of 874), with no differences detected between antiretroviral therapy regimens. Mother-to-child transmission rates were lower in women who became pregnant on antiretroviral therapy than those initiating antiretroviral therapy during pregnancy (0.7% versus 5.7%; P = 0.01). In the latter group, each additional week of treatment reduced odds of transmission by 8% (95% confidence interval: 0.87 to 0.99, P = 0.02). Late initiation of antiretroviral therapy is associated with increased risk of mother-to-child transmission. Strategies are needed to facilitate earlier identification of HIV-infected women.

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Editors’ note: Viral suppression typically occurs after 10-16 weeks of antiretroviral therapy and this likely explains the strong association found in this study between duration of antiretroviral treatment and HIV transmission to infants, with each additional week of treatment reducing the risk of HIV transmission. Thus it is no surprise that women who were on antiretroviral treatment when they became pregnant were significantly less likely to transmit HIV to their infants than women who were identified as treatment-eligible during pregnancy. In fact, there were no transmissions among women who were on antiretroviral treatment for more than 32 weeks before delivery. What is surprising is that pregnancy was planned in only 28.6% of women who became pregnant on treatment and 31.4% of those who started treatment during pregnancy. Since all of these women knew their HIV status, better integration of family planning services with HIV services could help avoid unplanned pregnancy and reduce infant infections even further.