Pfizer Covid vaccine is 85% effective after first shot: Study

Jerusalem - Israeli study finds reduction in symptomatic Covid-19 within 15 to 28 days after receiving first dose.

The first dose of Pfizer Inc’s COVID-19 vaccine is 85% effective, a study of healthcare workers at an Israeli hospital has found, potentially fuelling a debate over the recommended two-dose schedule as governments try to stretch out supplies.

The Sheba Medical Center’s findings compare with overall efficacy of around 95% in a two dose regimen 21 days apart for the shot developed with Germany’s BioNTech.

The Sheba study, to be published in The Lancet medical journal, comes a day after Canadian researchers suggested that the second Pfizer dose be delayed given the high level of protection from the first shot in order to increase the number of people getting vaccinated.

Their research showed efficacy of 92.6% after the first dose, based on an analysis of the documents submitted by the drugmaker from its late-stage human trials to the U.S. Food and Drug Administration in December.

The FDA said in December data from those trials showed that the vaccine began conferring some protection to recipients before they received the second shot, but more data would be needed to assess the potential of a single-dose shot.

Pfizer has said alternative dosing regimens of the vaccine have not been evaluated yet and that the decision resided with the health authorities.