What are the differences between the updated vaccines (e.g. updated Moderna/Spikevax or Pfizer BioNTech/Comirnaty) and the original vaccines?

Question

Accepted Answer

The updated Pfizer-BioNTech/Comirnaty and Moderna/Spikevax COVID-19 vaccines target newer strains of virus compared to the older versions of vaccines, can provide a stronger immune response against emerging strains, and therefore may confer better protection against COVID-19. The safety profiles of the updated vaccines are comparable to that of previous versions.

What are the differences between the updated vaccines (e.g. updated Moderna/Spikevax or Pfizer BioNTech/Comirnaty) and the original vaccines?

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