evidence: Here, we illustrate the potential total cost of Pfizer and Moderna COVID-19 vaccines, based on their publicly-announced expected prices, once they enter the U.S. commercial market. Specifically, we compare the average price paid by the federal government for the COVID-19 bivalent boosters to the estimated average commercial prices that have been suggested by manufacturers, and calculate an overall cost for purchasing vaccines for the adult population (ages 18 and older) across different scenarios of vaccine uptake (we only estimate costs for purchasing a single vaccine dose under different population uptake scenarios though it is possible that additional boosters will be needed on an annual or some other regular basis). While four COVID-19 vaccines have been authorized or approved for use in the United States, we focus our analysis only on Pfizer and Moderna vaccines, which account for almost all doses administered in the U.S. (97% as of March 22) and approximately 80% of all federal funding spent on COVID-19 vaccines. [...] - https://www.medicalcountermeasures.gov/app/barda/coronavirus/covid19.aspx - https://www.medicalcountermeasures.gov/newsroom/2020/modernamanufacturing - https://investors.modernatx.com/news/news-details/2020/Moderna-Announces-Supply-Agreement-with-U.S.-Government-for-Initial-100-Million-Doses-of-mRNA-Vaccine-Against-COVID-19-mRNA-1273/default.aspx - https://www.medicalcountermeasures.gov/newsroom/2020/moderna/ [...] This includes vaccines that have been authorized for use in the United States (vaccines from Pfizer, Moderna, J&J, and Novavax) as well as others that either did not make it past the clinical trial phase or for which manufacturers have not sought authorization (vaccines from Merck/IAVI, Sanofi/GlaxoSmithKline and Astra-Zeneca).