The coronavirus vaccine developed by Oxford University and AstraZeneca was 79% effective in a large US trial at preventing symptomatic illness, and was 100% effective against severe or critical disease and hospitalization.
The UK drugmaker published the first data from a study of more than 30,000 volunteers on Monday. The results are good news for older adults, who made up about a quarter of the tests, after trials last year failed to provide conclusive data for that age group due to a lack of participants over the age of 65.
The findings should go some way to bolstering confidence in the shot globally after confusion over the true efficacy of the vaccine and the best dosing regimen has impacted take-up, particularly in Europe.
Trials in the U.K. and Brazil last year produced a range of readings due to different dosing amounts and regimens used, and at least 10 countries in the European Union only approved the shot for under-65s initially. Many have since reversed that decision after more data from real world use showed the shot was highly effective in older people.
AstraZeneca said an independent safety committee conducted a specific review of the blood clots in the U.S. trial, as well as cerebral venous sinus thrombosis (CVST), which is an extremely rare blood clot in the brain, with the help of an independent neurologist.
The London-listed company said the panel found “no increased risk of thrombosis or events characterized by thrombosis among the 21,583 participants receiving at least one dose of the vaccine. The specific search for CVST found no events in this trial.”
The partners will prepare the data to apply for approval from the U.S. Food and Drug Administration (FDA), University of Oxford professor Sarah Gilbert told BBC radio. The preparation will take a few weeks, she added.