The impact of "Option B" on HIV transmission from mother to child in Rwanda: An interrupted time series analysis

Abstract

Background: Nearly a quarter of a million children have acquired HIV, prompting the implementation of new protocols-Option B and B+-for treating HIV+ pregnant women. While efficacy has been demonstrated in randomized trials, there is limited real-world evidence on the impact of these changes. Using longitudinal, routinely collected data we assessed the impact of the adoption of WHO Option B in Rwanda on mother to infant transmission.

Methods: We used interrupted time series analysis to evaluate the impact of Option B on mother-to-child HIV transmission in Rwanda. Our primary outcome was the proportion of HIV tests in infants with positive results at six weeks of age. We included data for 20 months before and 22 months after the 2010 policy change.

Results: Of the 15,830 HIV tests conducted during our study period, 392 tested positive. We found a significant decrease in both the level (-2.08 positive tests per 100 tests conducted, 95% CI: -2.71 to -1.45, p < 0.001) and trend (-0.11 positive tests per 100 tests conducted per month, 95% CI: -0.16 to -0.07, p < 0.001) of test positivity. This represents an estimated 297 fewer children born without HIV in the post-policy period or a 46% reduction in HIV transmission from mother to child.

Conclusions: The adoption of Option B in Rwanda contributed to an immediate decrease in the rate of HIV transmission from mother to child. This suggests other countries may benefit from adopting these WHO guidelines.

Fig 1. The rate of HIV-positive six-week tests per 100 tests conducted prior to and following the implementation of Option B in Rwanda.

The dashed vertical line represents the first month in which we expected to see the results of Option B adoption (February 2011, 3 months after the implementation of Option B in November 2010). The solid red lines show the fitted values from the interrupted time series model, and the dashed red line the predicted counterfactual trend absent the policy change.