A single dose of Pfizer and BioNtech’s COVID-19 vaccine cuts the number of asymptomatic infections and could significantly reduce the risk of transmission of the virus, results of a UK study found on Friday.
Researchers analysed results from thousands of COVID-19 tests carried out each week as part of hospital screenings of healthcare staff in Cambridge, eastern England.
“Our findings show a dramatic reduction in the rate of positive screening tests among asymptomatic healthcare workers after a single dose of the Pfizer-BioNTech vaccine,” said Nick Jones, an infectious diseases specialist at Cambridge University Hospital, who co-led the study.
After separating the test results from unvaccinated and vaccinated staff, Jones’ team found that 0.80% tests from unvaccinated healthcare workers were positive.
This compared with 0.37% of tests from staff less than 12 days post-vaccination – when the vaccine’s protective effect is not yet fully established – and 0.20% of tests from staff at 12 days or more post-vaccination.