Critical to Success

Factors relating to the manufacture, distribution and public acceptance of a COVID-19 vaccination program, as well as the severity of the pandemic, will contribute more to the success of the program than the efficacy of the vaccine itself, YSPH-led research predicted.

The research published in the journal Health Affairs in late 2020 came as the global effort to develop COVID-19 vaccines for approval by the Food and Drug Administration and large-scale distribution was nearing completion.

For instance, would a vaccine that has limited impact on transmission but significantly reduces progression to a more severe level of disease be acceptable? Alternatively, how might such a vaccine be compared with one that lowers susceptibility to infection but has no impact on disease progression? Once vaccination begins, what individual and public health benefits should the public expect from vaccines based on their performance in clinical trials? Finally, what other factors will shape the success of COVID-19 vaccination programs?

Investigators led by YSPH Professor A. David Paltiel, MBA., Ph.D., began by assembling data on the epidem-iology of SARS-CoV-2 and the natural history of COVID-19. They then used an original mathematical model to estimate cumulative infections, hospitalizations and deaths. Furthermore, they characterized the success of a vaccination program based on a number of inter-acting factors: the efficacy of the vaccine, the speed of manufacturing and distribution, the persuasiveness of public campaigns to promote vaccine acceptance, and the severity of the pandemic when the vaccine is introduced into the community.

“Infrastructure will contribute at least as much to the success of the vaccination program as will the vaccine itself,” said Paltiel. “The population benefits of vaccination will decline rapidly in the face of manufacturing or deployment delays, significant vaccine hesitancy or greater epidemic severity.”

The findings highlighted the urgent need for health officials to invest greater financial resources and attention to vaccine production and distribution programs and to redouble efforts to promote public confidence in COVID-19 vaccines, said Jason L. Schwartz, Ph.D., associate professor in the Department of Health Policy and Management at YSPH and one of the authors of the study.

“Even with a highly effective vaccine, we will still need sustained adherence to masking, physical distancing and other mitigation practices for some time to bring the public health crisis under control,” Schwartz said.