Updated: AstraZeneca COVID-19 vaccine candidate proves effective in Phase III trial

The vaccine candidate met the primary efficacy endpoint in preventing COVID-19 in an interim analysis.

UPDATE: U.S. health authorities has expressed concern that study results detailed below are based on outdated data. The National Institute of Health has urged AstraZeneca to work with the Data and Safety Monitoring Board to review the data and make sure the data released is the most-current.

The AstraZeneca COVID-19 vaccine candidate, AZD1222, proved 79 percent effective at preventing symptomatic infections with the disease in a U.S. Phase III trial.

According to a news release, AZD1222 was also shown to have 100 percent efficacy at preventing severe COVID-19 and hospitalization in an interim safety and efficacy analysis based on 32,449 participants. Efficacy was consistent across ethnicity and age, and in participants 65 years old and older efficacy was shown to be 80 percent.

The trial found that AZD1222 was well-tolerated, and the data safety monitoring board identified no safety concerns in connection to the vaccine and no increased risk of thrombosis or events characterized by thrombosis, the release says.

This is welcome news as Politico reports that confidence in the candidate has fallen in countries where it is approved after several countries in the European Union paused or limited its use over a fear of blood clots.

“These findings reconfirm previous results observed in AZD1222 trials across all adult populations but it’s exciting to see similar efficacy results in people over 65 for the first time,” Ann Falsey, professor of medicine at University of Rochester School of Medicine, and co-lead principal investigator for the trial, says in the release. “This analysis validates the AstraZeneca COVID-19 vaccine as a much-needed additional vaccination option, offering confidence that adults of all ages can benefit from protection against the virus.”

The release says that the company will seek emergency use authorization in the coming weeks. If it is granted, AZD1222 will join vaccines created by Pfizer, Moderna, and Johnson & Johnson which have already received emergency use approval.

An influx of more vaccines will only speed up the already quickly moving effort to vaccinate people across the U.S. President Joe R. Biden’s goal of getting 100 million vaccinations in the first 100 days of his administration was completed in only 58 days.