Strict adherence to daily PrEP is especially important in pregnancy, investigators conclude. Washington DC. 10th March 2020. Among African adolescent girls and young women who took HIV pre-exposure prophylaxis (PrEP) daily, levels of the PrEP drug tenofovir were more than 30% lower in those who were pregnant than in those who had recently given birth. All 40 study participants took PrEP under direct observation, confirming their near-perfect adherence. PrEP drug levels were lower to a similar degree in the pregnant African adolescent girls and young women compared to American men and non-pregnant, non-lactating women who took PrEP daily under direct observation in an earlier study. These findings from the NIH-funded IMPAACT 2009 study were reported at the Conference on Retroviruses and Opportunistic Infections (CROI). The study investigators suggest that nonetheless, daily PrEP may provide substantial protection for pregnant African adolescents and young women as part of a comprehensive HIV prevention program. “Adolescent girls and young women in sub-Saharan Africa, including those who are pregnant or have recently given birth, urgently need safe, desirable and effective HIV prevention tools,” said Anthony S. Fauci, M.D., director of the National Institute of Allergy and Infectious Diseases (NIAID) at NIH. “While taking PrEP daily as directed is important for everyone who receives it, these new data suggest daily adherence to PrEP will be especially critical for pregnant adolescents and young women. Additional research is needed to determine the level of protection that daily PrEP can provide this population.” NIAID is a co-funder of IMPAACT 2009. The substantially lower drug concentration found in dried blood spots from pregnant African adolescents and young women in the study does not necessarily indicate a lower PrEP efficacy for this group, according to the IMPAACT 2009 investigators. The response to any drug follows a curve that rises from zero as the dose increases until the curve reaches a plateau where a range of doses achieves a sufficient biological response to have the desired effect—in this case, preventing HIV infection. Based on available data, the study investigators believe the drug concentration in the target cells of pregnant adolescents and women…