PrEP Seguro: Antiretroviral-based HIV Prevention Among Men at High Risk in Mexico

"If hair testing shows that a participant has taken PrEP pills about 5-7 times in the previous week, he will receive a grade A; if he has taken PrEP pills about 3-4 times in the previous week he will receive a grade B; and if he has taken PrEP pills only 2 times or less, he will receive a grade C. For those in the CEI group, if participant gets an A, he receives two additional prizes; if he gets a B, he receives one additional prize; and if he gets a C, he receives no additional prizes."