Single Covid dose cuts risk to care home residents by 62%

One dose of the coronavirus vaccine cuts the risk of care home residents getting the disease by 62 per cent, a new study has found. Scientists at University College London (UCL) discovered infection rates fell by 56 per cent four weeks after the first jab and by 62 per cent by the time five weeks had elapsed.

The study was among the first to investigate how well the Covid vaccines protect the elderly. It took 10,412 participants into consideration across 310 care homes between December and mid-March. The conclusion was there was a substantial level of protection for those in this demographic after just one dose.

Dr Laura Shallcross, clinical lecturer at UCL, said: “A single dose has a protective effect that persists from four weeks to at least seven weeks after vaccination. 

“Vaccination reduces the total number of people who get infected, and analysis of lab samples suggests care home residents who are infected after having the vaccine may also be less likely to transmit the virus.”

Scientists analysed data from PCR tests and compared the numbers prior to vaccination and after. Both the Pfizer and Oxford-AstraZeneca vaccines were issued to participants. Samples taken from positive Covid tests 28 days or more after the first dose were also found to contain less viral material, indicating a lower level of transmissibility.

The study also took the UK variant that was prevalent during the second wave of the pandemic into consideration. Despite being known to be easily spread, scientists found both of the vaccines were effective at quashing it.

Professor Chris Whitty, chief medical officer, 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.”

Research will continue to see how effective a first dose is during the period of eight to 12 weeks post-vaccine. Then, it will also look at the impact of a second dose, which is recommended to be given within 12 weeks of the first jab.

This ongoing study will be used to inform policy decisions on disease control measures in care homes. Understanding the level of protection provided by the vaccine in older people will facilitate careful planning in areas such as visiting restrictions to weigh up the risks and benefits.