A single dose of the COVID-19 vaccine made by pharmaceutical company Pfizer PFE,
and its partner BioNTech BNTX,
reduces infections and lowers risk of transmission, according to a new study.
A January study by the Cambridge University Hospitals National Health Service Foundation Trust and the University of Cambridge looked at health workers, where comparable numbers of vaccinated and unvaccinated workers were screened.
It found that 26 of the 3,252, or 0.8%, tests of unvaccinated health workers were positive. This compares with 13 of 3,535 or 0.37% health worker tests less than 12 days after vaccination, and four of 1,989, or 0.2%, health worker tests 12 days or more after vaccination.
“This is great news – the Pfizer vaccine not only protects against SARS-CoV-2 disease but also helps prevent infection, reducing the chance of the virus being passed on to others,” said Dr. Mike Weekes, an infectious disease specialist who led the study.
This suggests a fourfold increase in the risk of asymptomatic COVID-19 infection in health workers vaccinated for more than 12 days, the researchers said, halving the infection rate for those vaccinated for less than 12 days. The study has not been peer-reviewed.
The Pfizer BioNTech vaccine is given in two doses. In the US, the interval between doses is three weeks, while in the UK, the interval is up to 12 weeks.
A growing body of evidence shows how effective the Pfizer-BioNTech vaccine has been in the UK and Israel, two of the countries at the forefront of mass vaccination.