A new study of the Pfizer/BioNTech coronavirus vaccine shows it offers 85% protection after its first dose.
The study of more than 7,000 healthcare workers at Israel’s largest hospital, the Sheba Medical Center, has been published in the Lancet medical journal.
The findings compare with the overall efficacy of about 95% in a two dose regime 21 days apart.
Out of the 7,214 hospital staff who received their first dose in January, there was an 85% reduction in symptomatic Covid-19 within 15 to 28 days.
The peer-reviewed study also found a 75% overall reduction of infections – including in asymptomatic cases detected by testing.
The findings could potentially fuel a debate over the recommended two-dose schedule and boost the UK government’s decision to delay the second dose to up to 12 weeks.
“This groundbreaking research supports the British government’s decision to begin inoculating its citizens with a single dose of the vaccine,” said Arnon Afek, deputy director-general of Sheba Medical Center.
Professor Eyal Leshem, an infectious disease expert and director of Sheba’s Institute for Travel and Tropical Medicine, told Sky News: “This is first real-world evidence of effectiveness that shows up after the first dose of the vaccine.
“We had some hints from the clinical trials and some calculations that were made based on the clinical trial [but] this shows early effectiveness, even before the second dose was administered.”
But Gili Regev-Yochay, an epidemiologist behind the study, cautioned that the study was conducted on “mostly young and healthy” people. “We don’t have many [staff] here aged over 65,” she told reporters.
The pharmaceutical giant Pfizer declined to comment on the data, saying it was doing its own analysis of “the vaccine’s real-world effectiveness in several locations worldwide, including Israel”.
Pfizer has said alternative dosing regimens of its vaccine have not yet been evaluated and that the decision resided with the health authorities.
It comes a day after researchers in Canada suggested the second Pfizer dose be delayed in order to increase the number of people getting vaccinated.