Care home residents see infection rate fall by 62% five weeks after receiving Covid vaccine

Coronavirus infections among care home residents fell by 62 per cent, five weeks after they received their first vaccine dose, according to initial results from the Vivaldi study.

The study is a collaboration between researchers from University College London (UCL) and the University of Birmingham and care providers including Four Seasons Healthcare, HC-One, The Orders of St John Care Trust, and Friends Of The Elderly.

Researchers examined data on 10,412 elderly care home residents from 310 care homes between December and mid-March and looked at the number of infections confirmed with PCR tests within specific time periods after vaccination compared to the number of infections beforehand.

They calculated the risk of infection was 56 per cent lower from four weeks after a single dose of either the Pfizer or Oxford-AstraZeneca vaccine and 62 per cent lower after five weeks.

The substantial protection lasted until at least seven weeks after vaccination, which the researchers say 'provides some evidence' to support the UK’s decision to extend the dose interval.

Laura Shallcross, from UCL’s Institute of Health Informatics, said: “Our findings show that a single dose has a protective effect that persists from four weeks to at least seven weeks after vaccination.

“Analysis of lab samples suggests that care home residents who are infected after having the vaccine may also be less likely to transmit the virus.”

The study also found any residents in England who were infected after having the vaccine may also be less likely to transmit the virus.

Chief medical officer for England Professor Chris Whitty said: “These data add to the growing evidence that vaccines are reducing Covid-19 infections and doing so in vulnerable and older populations, where it is most important that we provide as much protection from Covid as possible.”

Further research is also needed to examine how effective a first dose is after eight to 12 weeks and the impact of a second dose.

Minister for Care Helen Whately said: “This virus sadly has the most serious and profound effect on older people living in care homes and making sure they are protected has been our priority for the last year.

“It is brilliant to see this is having the positive effect the science suggested, not only by preventing death, but also reducing the chance of infection.

“This is particularly important in keeping those most at risk from the virus safe.”