What are the challenges in developing information around mixing-and-matching COVID-19 vaccines and therapies?

By Rachel Sachs, Jacob S. Sherkow, Lisa Larrimore Ouellette, and Nicholson PriceThe FDA has now authorized three vaccines and several treatments (including both monoclonal antibodies and small-molecule drugs) for the prevention and treatment of COVID-19. But the initial evidence supporting these products’ introduction into the market did not include information about how they might work together. Nevertheless, information about mixing-and-matching COVID-19 vaccines and therapies would be highly valuable not only to physicians and their patients, who must already make decisions about what treatment options to pursue under conditions of uncertainty (if the treatments are available), but also for policymakers, who want to know what products to prioritize for investment. Why is it so difficult to obtain this information? How can policymakers encourage its development? What, if anything, is known about mixing-and-matching COVID-19 vaccines and therapies?A growing body of…