Head of Research Institute of Pharmacovigilance Sciences, Drug Safety Research Unit Southampton, United Kingdom
Background: Safety issues following COVID-19 vaccination were observed early in vaccination programmes, however there was limited observational data to determine their incidence. Results of pharmacoepidemiology (PE) studies investigating adverse events were produced at unprecedented speed, and it is important to apply lessons learned from the pandemic to future drug safety issues where rapid production of results is warranted.
Objectives: To suggest how methods of pharmacoepidemiology studies conducted during the COVID-19 pandemic can be applied to future drug safety issues which require rapid assessment.
Methods: A review of regulatory decisions and communications surrounding COVID-19 vaccines was conducted. Early pharmacoepidemiological research published on the identified safety concerns were reviewed. Methodology which allowed rapid production of results was identified and summarised.
Results: The most significant signals which have been associated with COVID-19 vaccines were clotting with concurrent thrombocytopenia following adenovirus vector vaccines and myocarditis and pericarditis following mRNA vaccines. Early PE study publications covering clotting after the Oxford-AstraZeneca vaccine ChAdOx1-S included the study by Pottegård et al., published in BMJ on 28 April 2021 and covering the population of Denmark. A PE study on myocarditis following the Pfizer/BioNTech vaccine BNT162b2 in Israel was published in the New England Journal of Medicine by Mouch et al. on 28 May 2021. From the date of vaccine launch in Denmark and Israel, these studies were published within 129 days and 152 days, respectively. Both studies provided vital information on the events of interest early in vaccination roll-out. We must learn from these rapid publications, to ensure timely production of robust results in future health crises or pandemics. We must also consider what we as researchers need from data sources, publishers, and other external stakeholders to facilitate this, such as accelerated access to data and fast-track publishing.
Conclusions: In observational research, there is often a lag between study start and publication of results of many months, if not years. PE studies which produce robust and reliable evidence quickly, including longer-term studies with early interim reports, may contribute to early regulatory decision-making or support early access programmes or emergency use in future, therefore this is of utmost importance.
