Care homes need to be vigilant for outbreaks of COVID-19, even after residents have received two doses of the vaccine, according to new research being presented.

Martin Martinot, of the Hopitaux Civils de Colmar, Colmar, France, and colleagues studied an outbreak of COVID-19 that began in a care home in eastern France a month after a campaign to double vaccinate residents and staff with the Pfizer-BioNTech jab had ended.

Seventy (75%) of the residents and 38 (52%) of the staff were fully vaccinated by mid-February 2021.

Tests on samples of blood taken by the researchers on April 6 showed that all but one of the fully vaccinated residents had antibodies against COVID-19.

The outbreak started on March 15 and, over the next seven weeks, 24/93 residents (26%) and 16/73 staff (22%) were infected by the SARS-CoV-2 virus. Infected residents were older, with an average age of 91, than the uninfected residents, where the average age was 87.

Twelve out of the 24 infected residents had not been fully vaccinated. None of the infected staff had been vaccinated. Analysis showed that the unvaccinated residents were three times more likely to develop COVID-19 than those who had had two doses of the vaccine.

You can find more information about this study in an article from newswise.