Five years of Research and Development of COVID-19 vaccines:regulation, policy, and implications for public health

When SARS-CoV-2 entered the world stage in 2020, a global sense of urgency and collaboration between scientists, companies, funders and regulators facilitated the development of safe and effective COVID-19 vaccines. The unsurprising (and yet unanticipated) rapid evolution of new variants led to concerns about continued vaccine efficacy by late 2021, which, in some countries, led to government overreach. This had the unfortunate further consequence of reducing confidence in public health authorities and in vaccines.  Now that immunity to the virus has increased and rates of evolution have slowed, benefits of vaccination are more difficult to demonstrate.  Nonetheless, COVID-19 still contributes to significant morbidity and mortality, raising important questions regarding optimal public health response, including target population, frequency of administration, and composition for future vaccines.