A single dose of the Oxford vaccine may reduce transmission of coronavirus by two-thirds, according to a new study. The news provides a major boost to the UK’s recommendation that the second jab should be delayed for up to 12 weeks. Researchers said the first dose of the Oxford/AstraZeneca jab offers protection of 76% for up to three months and may reduce transmission by 67%, with efficacy rising to 82.4% after the second dose 12 weeks later. The data from the study by the University of Oxford, which has not yet been peer-reviewed, supports the four to 12-week prime-boost dosing interval that many global regulators have recommended.