Ethics approval and consent to participate
All procedures performed involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Kenya Medical Research Institute Scientific and Ethics Review Unit (KEMRI/SERU/CMR/P00093/3723) and University of California San Francisco Human Research Protection Program Institutional Review Board (IRB# 18–25134; Reference # 354239) reviewed and granted approval for all study activities described here.Informed written consent was obtained for all individual participants included in the study.