<p>Limited resources, technical expertise, and support, continue to challenge country capacity to maintain adverse event following immunization (AEFI) surveillance systems. Authorized COVID-19 vaccines proved to be safe and effective during clinical trials, however, the duration and sample size of these clinical trials may not detect rare but serious AEFIs or those with delayed onset. Hospital-based sentinel site surveillance (HBSSS_UG) aimed at monitoring vaccine safety in near real-time for adverse events of special interest (AESIs).</p>