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What are mRNA vaccines?

Both the Pfizer-BioNTech COVID-19 Vaccine and the Moderna COVID-19 Vaccine are lipid nanoparticle-formulated, nucleoside-modified mRNA vaccines encoding the prefusion spike glycoprotein of SARS-CoV-2, the virus that causes COVID-19. The 2023–2024 formula targets the Omicron XBB.1.5 sublineage of the spike protein. Visit this CDC website for more details about how mRNA vaccines work:

Last reviewed: October 26, 2023

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