Sign up for our daily briefing
Make your busy days simpler with Axios AM/PM. Catch up on what's new and why it matters in just 5 minutes.
Catch up on coronavirus stories and special reports, curated by Mike Allen everyday
Catch up on coronavirus stories and special reports, curated by Mike Allen everyday
Denver news in your inbox
Catch up on the most important stories affecting your hometown with Axios Denver
Des Moines news in your inbox
Catch up on the most important stories affecting your hometown with Axios Des Moines
Minneapolis-St. Paul news in your inbox
Catch up on the most important stories affecting your hometown with Axios Twin Cities
Tampa Bay news in your inbox
Catch up on the most important stories affecting your hometown with Axios Tampa Bay
Charlotte news in your inbox
Catch up on the most important stories affecting your hometown with Axios Charlotte
Photo: Rafael Henrique/SOPA Images/LightRocket via Getty Images
Peer-reviewed research published Tuesday confirms that the coronavirus vaccine developed by AstraZeneca and Oxford University is moderately effective at preventing infection, and it appears to keep people out of the hospital.
Why it matters: Some questions remain about AstraZeneca's vaccine, but the findings released in The Lancet medical journal help validate that the product works and is safe.
The big picture: When AstraZeneca's vaccine was administered in two standard doses, it was about 62% effective in preventing symptomatic infections.
- That's not as high as the roughly 95% efficacy reported by the Pfizer and Moderna vaccines, but AstraZeneca's has some other advantages over those two, including easier distribution.
- No one who had received both doses of the vaccine in AstraZeneca's trials developed a severe infection or had to be hospitalized.
The big question: The company accidentally gave some patients a modified dosing regimen — a half dose, followed by a full standard dose. In those patients, the vaccine registered 90% efficacy.
- Experts have puzzled over those results since AstraZeneca's initial release, and the research published Tuesday doesn't have many answers.
- The group that got the half-dose didn't include anyone older than 55 — the people most at risk for severe infection. We still don't know whether that skewed the results or AstraZeneca accidentally hit on a better dosage.
The lower initial dose also appeared to be much more effective in preventing asymptomatic spread — a critically important part of stopping the virus from spreading.