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A SARS-CoV-2 Alpha outbreak was detected in a nursing home after residents and staff had completed vaccination with BNT162b. In a retrospective cohort study, we estimated an age-adjusted vaccine effectiveness of 88% [95% confidence interval (95%CI) 41-98%] against hospitalization/death. Ct values at diagnosis were higher with longer intervals since the second vaccination [>21 vs. ≤21 days: 4.82 cycles, 95%CI: 0.06-9.58]. Secondary attack rates were 67% lower in households of vaccinated [2/9 (22.2%)] than unvaccinated infected staff [12/18 (66.7%); p=0.046]. Vaccination reduced the risk of severe outcomes, Ct values and transmission, but not fully. Non-pharmaceutical interventions remain important for vaccinated individuals.

The blood groups were analysed of staff and patients (N=45) infected during two nosocomial outbreaks of norovirus gastroenteritis at a German University hospital. Persons with O phenotype were significantly less affected than was expected from the normal distribution of blood group types in Southwest Germany (OR 2.45; 95% CI 1.22-4.95; P=0.01).

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