Evolution and Opportunities: Vaccine Pharmacovigilance in Australia

Abstract

Immunisation has an immense impact on preventing morbidity and mortality worldwide. Although vaccine safety is demonstrated in pre-licensure clinical trials, post-marketing surveillance is essential to ensure an ongoing, positive benefit-risk profile in the population. In Australia, a safety issue was identified after febrile seizures were associated with one brand of influenza vaccine in 2010. These events prompted the modification and strengthening of vaccine pharmacovigilance systems; however, additional pharmacovigilance opportunities exist. This thesis hypothesises that multi-faceted and adaptive vaccine pharmacovigilance methods, implemented strategically, are necessary to monitor vaccine safety in Australia and to inform ongoing benefit–risk assessment for vaccines and immunisation programs. Further, this thesis proposes that Australia can contribute to an international body of evidence through strengthening its own systems. This thesis assesses the value of current vaccine pharmacovigilance systems through analysis of cumulative data from multiple sources, including passive and active surveillance data, and a novel primary care data source. These analyses affirm the safety profile of the vaccines under investigation and highlight the validity of the systems and methods used. The limitations of individual systems are identified, including the challenges in ascertainment of hospitalised events and in making comparisons to unvaccinated populations. A final qualitative evaluation draws on the perspectives of expert informants to consider progress since 2010 and whether current systems are sufficiently robust to detect and investigate a potential safety signal, including for COVID-19 vaccines. The thesis concludes with five recommendations to strengthen Australia’s country-level systems and enhance its global contribution to vaccine pharmacovigilance.