One dose of the Pfizer and AstraZeneca vaccines has cut care home COVID-19 infections by almost two-thirds.
The University College London (UCL) research analysed data from 10,412 residents in 310 care homes, the BBC reported.
UCL’s Dr Maddie Shrotri said: “Our data suggests that both vaccines are effective in frail, older adults.”
The study also found that people who caught the virus after being vaccinated could be less infectious.
Care home COVID-related deaths have fallen dramatically since the launch of the vaccinations roll-out programme in December.
Having peaked at just under 2,000 deaths per week at the end of January, there were just 250 during the week ending 12 March.
Dr Laura Shallcross, a public health medicine consultant at the Institute of Health Informatics at UCL, said: “Our findings show that a single dose has an effect that persists from four weeks to at least seven weeks after vaccination.
“We can also infer that the vaccines protect against the highly transmissible UK variant, as this was prevalent during the study period.”
Professor Chris Whitty, Chief Medical Officer for England, added: “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.”