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What a difference 12 months makes. Last year’s forecast for the top 10 drugs of 2021 did not even include two of the year’s eventual biggest sellers, the COVID-19 vaccines Comirnaty (tozinameran; Pfizer/BioNTech) and Spikevax (Moderna). The omission of two of the fastest-selling drugs in the pharmaceutical industry’s history was largely down to their emergency use authorizations (EUAs) in December 2020 and uncertainty around manufacturing capacity to deliver promised doses, making forecasting sales difficult.