|
 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.
The study and its results have yet to be independently peer-reviewed
by other scientists, but were published online as a preprint on
Friday.
This suggests a four-fold decrease in the risk of asymptomatic
COVID-19 infection amongst healthcare workers who have been
vaccinated for more than 12 days, and 75% protection, said Mike
Weekes, an infectious disease specialist at Cambridge University's
department of medicine, who co-led the study.
[to top of second column] |
 The level of asymptomatic
infection was also halved in those vaccinated
for less than 12 days, he said.
Britain has been rolling out vaccinations with both the Pfizer
COVID-19 shot and one from AstraZeneca since late December 2020.
"This is great news – the Pfizer vaccine not only provides
protection against becoming ill from SARS-CoV-2, but also helps
prevent infection, reducing the potential for the virus to be passed
on to others," Weeks said. "But we have to remember that the vaccine
doesn’t give complete protection for everyone."
Key real-world data published on Wednesday from Israel, which has
conducted one of the world's fastest rollouts of Pfizer's COVID-19
vaccine, showed that two doses of the Pfizer shot cut symptomatic
COVID-19 cases by 94% across all age groups, and severe illnesses by
nearly as much.
(Reporting by Kate Kelland; Editing by David Goodman and Jane
Merriman)
[© 2021 Thomson Reuters. All rights
reserved.] Copyright 2021 Reuters. All rights reserved. This material may not be published,
broadcast, rewritten or redistributed.
Thompson Reuters is solely responsible for this content
 |
