Table 2. Adaptive adherence support strategies.

Adaptive intervention	Decision rule
Non-response definition: TFV-DP levels <500 fmol/punch or missed refills prior to the Month 3 study visit
First offer monthly SOC counseling and WhatsApp group intervention; then add drug-level feedback with quarterly visits for non-responders and switch responders to quarterly SOC visits and continued WhatsApp groups	First-stage intervention option = {SOC + WhatsApp} IF evaluation = {non-response}, THEN second-stage intervention option = {DLFB + first-stage intervention option + quarterly study visits}. ELSE continue on first-stage intervention option with quarterly study visits
First, offer monthly SOC counseling and two-way SMS intervention; then add drug-level feedback with quarterly visits for non-responders and switch responders to quarterly SOC visits and continued two-way SMS	First-stage intervention option = {SOC + SMS} IF evaluation = {non-response}, THEN second-stage intervention option = {DLFB + first-stage intervention option + quarterly study visits}. ELSE continue on first-stage intervention option with quarterly study visits
First, offer monthly SOC counseling and WhatsApp group intervention; then add monthly follow-up visits with issue-focused adherence counseling for non-responders and switch responders to quarterly SOC visits and continued WhatsApp groups	First-stage intervention option = {SOC + WhatsApp} IF evaluation = {non-response}, THEN second-stage intervention option = {Monthly visits and specialized counseling + first-stage intervention option}. ELSE continue on first-stage intervention option with quarterly visits
First, offer monthly SOC counseling and two-way SMS intervention; then add monthly follow-up visits with issue-focused adherence counseling for non-responders and switch responders to quarterly SOC visits and continued two-way SMS	First-stage intervention option = {SOC + SMS} IF evaluation = {non-response}, THEN second-stage intervention option = {Monthly visits and specialized counseling + first-stage intervention option}. ELSE continue on first-stage intervention option with quarterly visits