AstraZeneca vaccine may reduce virus transmission, researchers say

Initial testing of AstraZeneca’s COVID-19 vaccine, developed in partnership with Oxford University, shows that it could decrease virus transmission in addition to protecting recipients, researchers announced on Tuesday.

Their study, which has not been peer-reviewed, indicated that the AstraZeneca vaccine could lower transmission after studying data from trials in the U.K., Brazil and South Africa.

Matt Hancock, the British health secretary, celebrated the initial research on Wednesday, telling the BBC that a vaccine that decreases transmission “will help us all get out of this pandemic.”

The data analysis, which experts told The New York Times needs to be further confirmed, also determined that a single dose of the AstraZeneca vaccine was 76 percent effective at protecting a person from contracting COVID-19 90 days after it was administered. 

The results also suggested that the amount of time between the two doses affected the effectiveness. At least a three-month delay between doses resulted in 82 percent effectiveness, while efficacy dropped to 55 percent with less than six weeks between shots.

Researchers noted that providing the doses three months apart “may be the optimal for rollout of a pandemic vaccine when supplies are limited in the short term.”

This analysis supports the strategy that several countries are taking to prioritize providing the first doses of the vaccine to residents, the Times noted.

The study only looked into the AstraZeneca vaccine and not the Pfizer-BioNTech and Moderna vaccines, the two currently available in the U.S.

The U.S. has ordered 300 million doses of the AstraZeneca vaccine, but the Food and Drug Administration is waiting to authorize it until the results from a clinical trial come out later this month.

–Updated on Feb. 4 at 8:03 a.m.