Unvaccinated nursing facility residents and staff had higher COVID-19 infection risk during R.1 variant outbreak

An observational outbreak investigation examined COVID-19 infections associated with the SARS-CoV-2 R.1 lineage variant at a skilled nursing facility in Kentucky following a vaccination program. The study compared outcomes between vaccinated and unvaccinated residents and healthcare personnel, though exact sample sizes and follow-up duration were not reported.

Unvaccinated residents had 3.0 times the risk of infection compared to vaccinated residents, while unvaccinated healthcare personnel had 4.1 times the risk. The vaccine was found to be 86.5% protective against symptomatic illness among residents and 87.1% protective among healthcare personnel. No absolute case numbers, p-values, or confidence intervals were reported for these effect estimates.

Safety and tolerability data were not reported. The study has several important limitations: it represents observations from a single facility outbreak, involves a variant newly introduced to the region, and lacks confidence intervals for the risk and effectiveness estimates. Causation cannot be established from this observational design.

For practice, this outbreak investigation suggests vaccination was associated with reduced infection risk and symptomatic illness during this specific facility outbreak with the R.1 variant. However, clinicians should recognize these findings come from observational data in a unique setting without statistical precision measures, limiting broader conclusions about vaccine effectiveness against this variant.