The first dose of the Pfizer vaccination is 85 per cent effective against the coronavirus infection between two and four weeks after inoculation, AFP reports citing a study published in the Lancet medical journal.

The survey was carried out on healthcare workers at the largest hospital in Israel, which on December 19 launched a mass vaccination campaign regarded as the world's fastest.

Israeli studies have found the Pfizer vaccine to be 95pc effective one week after a second jab, while the Lancet report focused on more than 9,000 medical staff at Sheba hospital near Tel Aviv.

Some 7,000 of them received the first dose and the rest were not inoculated.