Pfizer COVID-19 vaccine reduces transmission after a dose – UK study

LONDON (Reuters) – A single dose of the COVID-19 vaccine from Pfizer and BioNtech reduces the number of asymptomatic infections and can significantly reduce the risk of transmitting the virus, results of a British study found on Friday.

The researchers analyzed the results of thousands of COVID-19 tests performed each week as part of the hospital’s health team screenings in Cambridge, in eastern England.

“Our findings show a dramatic reduction in the rate of positive screening tests among asymptomatic healthcare professionals after a single dose of the Pfizer-BioNTech vaccine,” said Nick Jones, an infectious disease specialist at Cambridge University Hospital, who co-led the study.

After separating the test results from unvaccinated and vaccinated employees, Jones’ team found that 0.80% of the tests from unvaccinated healthcare workers were positive.

This compares to 0.37% of the team’s tests less than 12 days after vaccination – when the protective effect of the vaccine is not yet fully established – and 0.20% of the team’s tests 12 days or more after vaccination.

The study and its results have yet to be reviewed by independent peers by other scientists, but were published online as a preprint on Friday.

This suggests a four-fold reduction in the risk of asymptomatic COVID-19 infection among healthcare professionals who have been vaccinated for more than 12 days, and 75% protection, said Mike Weekes, an infectious disease specialist in the University’s medical department. from Cambridge, who co-led the study.

The level of asymptomatic infection was also halved in people vaccinated for less than 12 days, he said.

Britain has been implementing vaccines with the Pfizer COVID-19 vaccine and one from AstraZeneca since the end of December 2020.

“This is great news – the Pfizer vaccine not only provides protection against illness from SARS-CoV-2, but it also helps prevent infection by reducing the potential for the virus to be transmitted to others,” said Weeks. “But we have to remember that the vaccine does not offer complete protection for everyone.”

Important real-world data published on Wednesday in Israel, which carried out one of the world’s fastest launches of Pfizer’s COVID-19 vaccine, showed that two doses of Pfizer injection reduced symptomatic COVID-19 cases by 94% in all age groups, and almost as much serious illness.