JERUSALEM (Reuters) – The first dose of Pfizer Inc’s COVID-19 vaccine is 85% effective, a study of health professionals at an Israeli hospital concluded, potentially fueling a debate over the recommended two-dose schedule as governments try to stretch supplies.
The Sheba Medical Center’s findings compare to the overall efficacy of about 95% in a two-dose regimen 21 days apart for the injection developed with BioNTech from Germany.
The Sheba study, to be published in the medical journal The Lancet, comes a day after Canadian researchers suggest that the second dose of Pfizer be postponed due to the high level of protection from the first injection, in order to increase the number of people vaccinated.
The research showed 92.6% efficacy after the first dose, based on an analysis of the documents submitted by the pharmacist from her final human tests for the US Food and Drug Administration in December.
The FDA said in December that data from these tests showed that the vaccine started to provide some protection to recipients before they received the second injection, but more data would be needed to assess the potential for a single dose.
Pfizer said alternative vaccine dosing regimens have yet to be evaluated and that the decision rested with health officials.
Sheba said that among 7,214 hospital employees who received their first dose in January, there was an 85% reduction in symptomatic COVID-19 in 15 to 28 days. The overall reduction in infections, including asymptomatic cases detected by testing, was 75%.
Epidemiologist Sheba, Gili Regev-Yochay, warned that the cohort studied at the hospital was “mainly young and healthy”.
Unlike the Pfizer clinical trial, “we don’t have many (employees) here over 65,” she told reporters. But she also noted that Sheba’s study occurred during an outbreak of COVID-19 infections in Israel, which flooded hospitals with new cases.
Pfizer declined to comment on the data, saying in a statement that it was doing its own analysis of the “effectiveness of the vaccine in the real world in various locations around the world, including Israel”. The company hopes to use Israeli data to examine the vaccine’s potential to protect against COVID-19 from emerging variants, the drugmaker said.
Written by Dan Williams; Jane Merriman edition