JERUSALEM (Reuters) - 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.

Sheba said among 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.