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mRNA vaccines decreased number of new COVID-19 cases in nursing home population

Use of mRNA vaccinations, such as the Pfizer-BioNTech and Moderna vaccines, in nursing home populations was found to decrease the number of new cases of SARS-CoV-2 infection (the virus that causes the COVID-19 disease) in both vaccinated and unvaccinated residents. The findings were published as a correspondence in the New England Journal of Medicine.Older adult woman receives COVID-19 vaccine.

Researchers from Brown University School of Public Health, Genesis HealthCare, and Warren Alpert Medical School of Brown University used electronic health record data from 280 nursing homes across 21 states. They measured the number of residents who newly tested positive for SARS-CoV-2 between Feb. 15 and March 31 across three groups — those who had received at least one vaccine dose (18,242 residents), those who received both doses (13,048 residents), and those who had not received any vaccine (3,990 residents).

Researchers found that there were fewer cases in both vaccinated residents and unvaccinated residents during the study period, and of those cases, most were asymptomatic. Among the vaccinated residents, the number of new cases decreased from 4.5% (822 cases within two weeks of the first dose) to 1.4% (250 cases after two weeks) and from 1.0% (130 cases within two weeks of second dose) to 0.3% (38 cases after two weeks). Those who were unvaccinated also had a significant reduction in the number of new cases — 4.3% (173 cases within two weeks after first vaccination clinic) to 2.4% (97 cases after two weeks). Researchers suggested that widespread vaccine coverage in a facility, along with masks and other precautions, also helped provide some protection for unvaccinated residents. Notably, nursing homes located in counties with the highest number of new cases in the larger community had the most new cases among the study participant groups, but they still experienced large decreases.

These findings demonstrate the real-world ability of the mRNA vaccines in a nursing home population, a high-risk group, to decrease new infections. Further examination may clarify the impact of nursing home staff member vaccination rates on residents. Though the number of new cases decreased with vaccinations, the presence of any new cases highlights the need for continued vaccination efforts and other precautionary measures.

This research was supported by NIA grants 3P01AG027296-11S1 and U54063546-S5.

Reference: White EM, et al. Incident SARS-CoV-2 infection among mRNA-vaccinated and unvaccinated nursing home residents. N Engl J Med. 2021:NEJMc2104849. doi: 10.1056/NEJMc2104849. Epub 2021 May 19.