AIM/OBJECTIVE: To design and test the usability of case-based HIV microlearning lessons using WhatsApp groups. This paper reports on effectiveness and uptake. BACKGROUND: South Africa has the largest antiretroviral treatment program globally. National guidelines are regularly updated. Ongoing training of healthcare workers is vital but complicated by infrastructural, financial and human resource shortages. Innovative solutions are needed. DESIGN: A pragmatic, mixed methods, parallel group, cluster randomised trial. METHODS: Nurses and community health workers (CHWs) at 50 clinics in the Eastern Cape were invited to participate. Online questionnaires tested knowledge and retention of knowledge
retrospective folder reviews measured changes in patient care. Patient folders were sampled purposively pre-/post-intervention for clinical points learned. Descriptive and inferential analyses were performed. RESULTS: Uptake and participation were good: 232 (79 %) nurses and 207 (76 %) CHWs participated. 96 % of nurses and 88 % of CHWs read the lessons within two weeks. There was a significant intervention effect on knowledge, based on the online questionnaires: nurses (0.5 units
95 % CI 0.11-1.0
p = 0.0499) and CHWs (0.7 units
95 % CI 0.2-1.3
p = 0.004). 1083 patient folders were reviewed to compare changes in patient care between the study arms. Adjusting for pre-care differences between the arms, the intervention increased correct patient care by 21 % ( 95 % CI 10 %-32 %
p <
0.001) in the year after the training. CONCLUSIONS: WhatsApp-based microlearning improves knowledge and patient care. This, with the companion paper's data showing that it is well received and accepted, makes it a valuable option for simple, accessible, scalable continuing medical education for HCWs.