• A new study explored whether alternating arms for multidose vaccines could improve immunity.
• Examples of multidose vaccinations include those for COVID-19, measles mumps and rubella (MMR), and shingles.
• Multidose vaccinations can be received in the same or different injection site for each dose.
• Researchers say that switching arms for the initial and booster doses of mRNA COVID-19 vaccines helped improve subjects’ immune response and vaccine effectiveness.

The COVID-19 vaccine is still relatively new, and researchers are still interested in studying how to maximize its effectiveness.

Typically, people receive the COVID-19 vaccine in the upper arm, which has multidose options. Multidose vaccines can be received in the same or different injection site for each dose. Other examplesTrusted Source of multidose vaccines include those for measles mumps and rubella (MMR) and shingles.

A recent study published in The Journal of Clinical Investigation examined whether switching arms for two doses of the Pfizer BioNTech COVID-19 vaccine increased effectiveness.

Participants who switched arms for vaccine doses experienced a higher antibody response than those who received doses in the same arm.

The results showed this response increased over time in the subsequent follow-up visits.

These results point to a simple way to increase vaccine effectiveness. Future research could explore whether switching injection sites for other multidose vaccines could help improve immunity.