Researchers looked at a COVID-19 outbreak that happened at a skilled nursing facility in Kentucky after a vaccination program. The outbreak was caused by a specific variant of the virus called the R.1 lineage. They wanted to see how vaccination affected infection rates during this outbreak.
The study included both residents living at the facility and health care personnel working there. They compared people who had been vaccinated against COVID-19 with those who had not been vaccinated. The researchers found that unvaccinated residents had about 3 times higher risk of getting infected, while unvaccinated staff had about 4 times higher risk compared to their vaccinated counterparts.
For preventing symptomatic illness, the vaccine showed about 87% protection for both residents and staff. This was an observational study of just one outbreak at a single facility, so we should be careful about applying these numbers to other situations. The study didn't report confidence intervals for their estimates, which means we can't be sure how precise these numbers are. The findings suggest vaccination was associated with lower infection risk during this particular outbreak, but more research would be needed to understand how well these results apply elsewhere.
