A team of Israeli researchers on Friday showed that COVID-19 infections reduced by 75 per cent after the administration of the first dose of the Pfizer vaccine.

The data, published in the peer-reviewed Lancet medical journal, centred on a study of around 9,000 Sheba healthcare workers, around 7,000 of which received their first dose in January.

The researchers at Sheba Medical Center found a 75 per cent decrease in all infections and an 85 per cent reduction in symptomatic infections between 15-28 days after vaccination, The Jerusalem Post reported.

According to Gili Regev-Yochay, director of the hospital's Infectious Disease Epidemiology Unit, only 170 people became infected during the two week period. Of those who contracted the virus, 99 showed symptoms. Eighty-nine of the sick were unvaccinated.

She said the hospital is now completing research on the impact of the second dose, which she said researchers still believe is essential. However, she noted that the research supports the UK government's decision to spread out the time between the first and second shots of the vaccine in order to inoculate more people.

Regev-Yochay noted that there was at least one limitation on the data -- that hospital workers tend to be under the age of 65 and healthier than the rest of the population, so it is possible that fewer people got sick or showed symptoms for that reason.