Switching Arms for COVID-19 Vaccination Doses Might Enhance Immunity: What the Research Says

Enhanced Immunity with Contralateral Vaccination

Recent studies have shed light on a potentially impactful factor in COVID-19 vaccination strategies: the arm in which the vaccine is administered. Researchers found that switching arms for initial and booster doses of vaccinations can enhance immunity and improve vaccine effectiveness. This discovery could have significant implications for the development of booster dose recommendations and overall vaccination strategies.

Pfizer-BioNTech COVID-19 Vaccine Study

A study published in The Journal of Clinical Investigation involved almost 950 adults who received the Pfizer BioNTech COVID-19 vaccine. The participants were divided into two groups, with one receiving at least two doses in the same arm and the other receiving at least two doses in opposite arms. The study found that the group receiving vaccination doses in opposite arms had a better immune response, with higher levels of SARS-CoV-2 specific serum antibodies observed over time. This data suggests that switching arms during initial vaccination and boosting could produce stronger immunity and longer-lasting protection. However, more research is needed to verify these initial findings and expand data collection.

Increased Antibody Response and Neutralization Capacity

The same study showed that switching arms for the 2-dose COVID-19 vaccine was associated with as much as a 4-fold increase in antibody response and neutralization capacity. The contralateral cohort had significantly higher immune and antibody responses, especially against the Omicron variant. Similar results were observed in a real-world population of 1568 adults favoring contralateral boosting. The research suggests that contralateral placement of boosters can substantially increase vaccine-specific antibody responses following mRNA COVID-19 vaccination. Further investigation is needed to understand the relevance to other vaccines, particularly in children.

Implications for Multi-dose Vaccines

Research indicates that alternating the limb for each dose of the COVID-19 vaccine may provide extra protection against illness. This small boost in immunity could be significant for individuals who respond poorly to vaccines due to age or health conditions. While most people may not see much benefit from alternating arms at this point in the pandemic, further study could have implications for all multi-dose vaccines. The study showed that switching arms for COVID-19 vaccines increased blood antibody levels by as much as fourfold and resulted in a stronger immune response against both the original coronavirus and the omicron variant.

OHSU's Vaccination Approach

Oregon Health and Science University (OHSU) has been actively involved in coordinating a regional response to the COVID-19 pandemic, including the distribution of vaccines. OHSU defines 'fully vaccinated' as receiving both doses of a two-dose COVID-19 vaccine or one dose of a single-dose vaccine and waiting at least 14 days. They have organized appointment-only vaccination clinics for children as young as 6 months old and continue to offer vaccinations for individuals 12 years or older. OHSU still requires masks for ages 2 and older in certain areas and based on CDC guidance.