Pfizer COVID-19 vaccine reduces transmission after 1 dose, research shows

A single dose of Pfizer and BioNtech’s COVID-19 vaccine could significantly reduce the risk of transmission of the virus, a UK study found.

Researchers analyzed the results of thousands of COVID-19 tests conducted each week as part of hospital examinations of medical staff in Cambridge, England.

Mike Weekes, an infectious disease specialist in Cambridge University’s department of medicine who co-led the study, said: “This is great news – the Pfizer vaccine not only protects against SARS-CoV-2 disease, but also helps prevent infection, which reduces the chance of passing the virus to others.

“But we must not forget that the vaccine does not provide complete protection for everyone.”

The study also found that a single dose of the injection reduces the number of asymptomatic infections.

“Our findings show a dramatic decrease in the number of positive screening tests among asymptomatic health professionals after a single dose of the Pfizer-BioNTech vaccine,” said Nick Jones, infectious disease specialist at Cambridge University Hospital, another co-lead of the study. . .

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

This compares with 0.37% of staff tests less than 12 days after vaccination – when the protective effect of the vaccine has not yet been fully established – and 0.20% of staff tests 12 days or more after vaccination.

The study and its results have yet to be independently reviewed by other scientists, but were published online Friday.

This suggests a quadrupling the risk of asymptomatic COVID-19 infection in health workers vaccinated for more than 12 days, and 75% protection, Weekes said.

The level of asymptomatic infection was also cut in half in those vaccinated for less than 12 days, he said.

Great Britain has been conducting vaccinations with both the Pfizer COVID-19 injection and AstraZeneca’s injection since late December 2020. The US uses the Pfizer-BioNTech injection and a vaccine from Moderna Inc. in their vaccination program.

Key field data published Wednesday from Israel, which conducted one of the world’s fastest deployments of Pfizer’s COVID-19 vaccine, showed that two doses of the Pfizer injection reduced symptomatic COVID-19 cases by 94%. in all age groups, and serious illnesses decreased almost equally.