Adverse effect profile of COVID-19 vaccine in Northern Nigeria: a prospective observational study. Annals of African Medical Research, [S. l.], v. 8, 2025. DOI: 10.4081/aamr.2025.509. Disponível em: https://africa.pagepress.net/aamr/article/view/509. Acesso em: 29 apr. 2026.