Third-Dose mRNA Vaccine Produces Robust Humoral Response Among OAs

Third mRNA COVID-19 vaccinations in assisted living and nursing home (NH) residents mounted a robust humoral response with greater neuralization capacity when compared to second-dose vaccinations, according to authors of a study recently published in the Journal of Post-Acute and Long-Term Care Medicine.

“Continued monitoring of neutralization titers over time will determine the rate of degradation,” stated study authors.
Researchers examined SARS-CoV-2 neutralizing antibody titers after second- and third-dose vaccination in NH residents and third-dose vaccination in assisted living residents in Ontario, Canada.

In the study, 66% of NH residents received Moderna for all 3 doses, 16.5% received Pfizer for all 3 doses, and 17.5% received 2 doses of Pfizer and 1 dose of Moderna. Additionally, 61.1% of assisted living residents received 3 doses of Pfizer, 22.1% received 3 doses of Moderna, 14.7% received 2 doses of Pfizer and 1 dose of Moderna, and 2.1% received 2 doses of Moderna and 1 dose of Pfizer.

“For the equivalent 12 to 77 days post-vaccine period, residents post-third dose had substantially higher neuralization titers for both the wild-type and beta variant (P < .001),” stated study authors.
“For beta variant neuralization, 20.8% (11) of post-second dose residents were below the level of detection compared to none of the post-third dose residents (P < .001).”

Researchers noted that although 5.3% of assisted living residents were below detection (P < .05), there were no differences in median neutralization titers between NH and assisted living residents.
“Neutralization performance for the beta variant may not mimic performance for the omicron variant, which at the time of writing remains a concern,” concluded authors of the study.

Reference:
Zhang A, Breznik JA, Clare R, et al. Antibody responses to third-dose mRNA vaccines in nursing home and assisted living residents. J Am Med Dir Assoc. 2022. doi:10.1016/j.jamda.2021.12.035