The latest findings, from a lengthy study by scientists at Imperial College London and market research firm Ipsos MORI, were based on 98,233 samples taken between June 24 and July 12.
They showed that one in 160 people were infected with the coronavirus, with a prevalence rate of 1.21% for unvaccinated respondents and 0.40% for those who had been fully injected.
The study also found that people who were doubly vaccinated may be less likely to pass the virus on to others than those who did not receive a vaccine.
However, British officials and scientists have urged caution after the government relaxed all virus brakes in England on July 19, including the legal requirement to wear masks in certain indoor environments.
A US government document leaked last week warned that infections among fully vaccinated people are not as rare as previously believed, and such cases are highly contagious.
Paul Elliott, professor at the Imperial School of Public Health and director of the survey program, said the results “confirm our previous data showing that two doses of a vaccine provide good protection against infection. “.
“However, we can also see that there is always a risk of infection, because no vaccine is 100% effective, and we know that some people who have been doubly vaccinated can still get sick from the virus.
“So even with the easing of restrictions, we still need to act with caution to protect each other and reduce the rate of infections. “
The daily COVID-19 cases recorded by the UK Department of Health have declined since the rules were relaxed, while population surveys have suggested they may rise further, albeit at a slower pace.
The trend surprised experts and officials, who predicted an increase in new infections.
The Imperial-Ipsos preprint study – covering the period up to July 12 – showed that even then cases were increasing more gradually than in the previous month.
© Agence France-Presse