Strengthening vaccine pharmacovigilance in low- and middle-income countries using a multi-centre hospital based prospective surveillance approach

The capacity to rapidly detect and respond to emerging vaccine safety signals is critical for assuring public confidence in vaccination programmes. Clinical trials, despite their increasing size, cannot detect very rare or long-term adverse events following immunization (AEFIs) and do not represent the diversity of real-world populations, highlighting the need for effective post-licensure safety surveillance of vaccines. Spontaneous reporting remains the mainstay of vaccine safety monitoring in low- and middle-income countries (LMICs). Such passive surveillance systems are susceptible to under- and biased reporting and lack the capacity to identify long-term sequelae following vaccinations.
The present thesis aims to evaluate the potential of multi-centre hospital-based active surveillance approaches towards strengthening capacity for vaccine pharmacovigilance in LMICs. To achieve these objectives, the thesis established two prospective observational active vaccine safety surveillance networks across seven countries. The two large, multi-centre studies underpinning this thesis, collectively screened a cohort of over 160,000 individuals and identified over 40,000 serious perinatal, neonatal and paediatric adverse outcomes, syndromes and diseases in one primary, five secondary and 32 tertiary care hospitals across seven countries, over a span of 34 months. By generating background rates of adverse perinatal, neonatal, and paediatric conditions across diverse geographies and healthcare settings, it shows that hospitals in resource-constrained settings can effectively classify adverse outcomes and vaccine exposures using standardized definitions.
The thesis demonstrates the feasibility and potential of tailored multi-centre hospital-based active surveillance systems in India and other LMICs. These findings offer operational and scientific guidance for building robust and responsive post-licensure active vaccine safety surveillance systems in the future.