Single dose of Pfizer vaccine reduces transmission: Study

London: A single dose of Pfizer-BioNtech’s 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 health staff in Cambridge, England. “Our findings show a dramatic reduction in the rate of positive screening tests among asymptomatic health 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 tests from unvaccinated and vaccinated staff, Jones’ team found that 0.80% tests from unvaccinated health 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 is yet to be peer-reviewed. This suggests a four-fold decrease in the risk of asymptomatic infection amongst health workers who have been vaccinated for over 12 days, and 75% protection, said Mike Weekes of Cambridge University who also co-led the study.