Effects of highly active antiretroviral therapy duration and regimen on risk for mother-to-child transmission of HIV in Johannesburg, South Africa.

BACKGROUND

Limited information exists about effects of different highly active antiretroviral therapy (HAART) regimens and duration of regimens on mother-to-child transmission (MTCT) of HIV among women in Africa who start treatment for advanced immunosuppression.

METHODS

Between January 2004 to August 2008, 1142 women were followed at antenatal antiretroviral clinics in Johannesburg. Predictors of MTCT (positive infant HIV DNA polymerase chain reaction at 4-6 weeks) were assessed with multivariate logistic regression.

RESULTS

Mean age was 30.2 years (SD = 5.0) and median baseline CD4 count was 161 cells per cubic millimeter (SD = 84.3). HAART 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 HAART. Overall MTCT rate was 4.9% (43 of 874), with no differences detected between HAART regimens. MTCT rates were lower in women who became pregnant on HAART than those initiating HAART 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).

CONCLUSIONS

Late initiation of HAART is associated with increased risk of MTCT. Strategies are needed to facilitate earlier identification of HIV-infected women.