A single dose of the Oxford/AstraZeneca coronavirus vaccine offers a high level of protection for three months and cuts transmission by two-thirds, according to preliminary results of a new study. 

The analysis of data from three trials found that the first dose conferred on average 76% protection against symptomatic infections from three weeks until 90 days, and reduced transmission of the virus by 67%.

The Oxford University study, published in Preprints with The Lancet, found the efficacy from the recommended two standard doses of the vaccine administered three months apart to be 82.4%.

The news of a reduction in transmission rates from one dose of the vaccine could prove the “holy grail” of the global rollout, according to the former chair at Britain’s Faculty of Pharmaceutical Medicine.