By Jon Cohen
Science’s COVID-19 reporting is supported by the Pulitzer Center and the Heising-Simons Foundation.
Continuing the spate of stunning news about COVID-19 vaccines, the biotech company Moderna announced the final results of the 30,000-person efficacy trial for its candidate in a press release today: Only 11 people who received two doses of the vaccine developed COVID-19 symptoms after being infected with the pandemic coronavirus, versus 185 symptomatic cases in a placebo group. That is an efficacy of 94.1%, the company says, far above what many vaccine scientists were expecting just a few weeks ago.
More impressive still, Moderna’s candidate had 100% efficacy against severe disease. There were zero such COVID-19 cases among those vaccinated, but 30 in the placebo group. The company today plans to file a request for emergency use authorization (EUA) for its vaccine with the U.S. Food and Drug Administration (FDA), and is also seeking a similar green light from the European Medicines Agency.
The data released today bolster an interim report from the company two weeks ago that only analyzed 95 total cases but produced similarly impressive efficacy. “I would still like to see all of the actual data, but what we’ve seen so far is absolutely remarkable,” says Paul Offit, a vaccine researcher at the Children’s Hospital of Philadelphia who is a member of an independent committee of vaccine experts that advises FDA.
Moderna’s vaccine against SARS-CoV-2, the virus that causes COVID-19, relies on a novel technology that uses messenger RNA (mRNA) to code for a protein called spike that studs the surface of the pathogen. Pfizer and BioNTech have developed a similar mRNA vaccine against COVID-19 and also reported excellent results, with an efficacy of 95%, in the final analysis of their 45,000-person trial. In that study, which ended after 170 cases of COVID-19 were identified, only 10 severe cases occurred, and just one was in the vaccinated group.