JERUSALEM (Reuters) – The first dose of COVID-19 Pfizer Inc vaccine is 85% effective, a study by health workers at an Israeli hospital found that could fuel a debate over the recommended two-dose schedule in while governments are trying to expand supplies.
The findings of Sheba Medical Center compare to the overall efficacy of approximately 95% in a 21-day two-dose regimen for the vaccine developed with BioNTech in Germany.
The Sheba study, to be published in The Lancet, comes a day after Canadian researchers suggested delaying the second dose of Pfizer, given the high level of protection from the first blow, to increase the number of vaccinated people.
Their research showed a 92.6% efficacy after the first dose, based on an analysis of documents submitted by the drug manufacturer following its late human studies at the US Food and Drug Administration in December.
The FDA said in December that data from these studies showed that the vaccine began to provide some protection to recipients before receiving a second injection, but more data would be needed to assess the potential for a single-dose injection.
Pfizer said alternative vaccine dosing regimens have not yet been evaluated and the decision rests with health authorities.
Sheba said that of the 7,214 hospital staff who received the first dose in January, there was an 85% reduction in symptomatic COVID-19 within 15 to 28 days. The overall reduction in infections, including asymptomatic cases detected by testing, was 75%.
Gili Regev-Yochay, a Sheba epidemiologist, warned that the cohort studied at the hospital is “mostly young and healthy.”
Unlike the Pfizer clinical trial, “we don’t have many (staff) here over the age of 65,” she told reporters. But she also noted that the Sheba study took place during an increase in 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 conducting its own analysis of the “real-world effectiveness of the vaccine in several locations around the world, including Israel.” He hopes to use Israeli data to analyze the vaccine’s potential to protect against COVID-19 resulting from emerging variants, the drug manufacturer said.
Written by Dan Williams; Editing by Jane Merriman