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  • Administering Vaccines
  • General Issues

Why are some vaccinations given subcutaneously (SC) while others must be given intramuscularly (IM)?

In general, vaccines containing adjuvants (a component that enhances the antigenic response) are administered IM to avoid irritation, induration, skin discoloration, inflammation, and granuloma formation if injected into subcutaneous tissue. This includes most of the inactivated vaccines, with a few exceptions (such as IPV and pneumococcal polysaccharide vaccines, which may be given either SC or IM). Vaccine efficacy may also be reduced if not given by the recommended route.

Last reviewed: December 28, 2022

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