Moderna COVID-19 vaccine 94.5 percent effective in major trial

Moderna, a biotechnology company based in Cambridge, Massachusetts, announced this morning its novel coronavirus (COVID-19) vaccination, mRNA-1273, appears to be 94.5 percent effective, according to preliminary data from its ongoing clinical study.

The study, known as the COVE study, enrolled more than 30,000 participants in the U.S. According to the announcement, the primary endpoint of the Phase 3 study is based on the analysis of COVID-19 cases confirmed and adjudicated starting two weeks following the second dose of vaccine. This first interim analysis was based on 95 cases, of which 90 cases of COVID-19 were observed in the placebo group versus five cases observed in the mRNA-1273 group, resulting in a point estimate of vaccine efficacy of 94.5. The 95 COVID-19 cases included 15 older adults, ages 65 years and older. and 20 participants identifying as being from diverse communities, the announcement said.

A secondary endpoint analyzed severe cases of COVID-19 and included 11 severe cases, as defined in the study protocol, in this first interim analysis. All 11 cases occurred in the placebo group and none in the mRNA-1273 vaccinated group, according to the announcement.

The interim analysis included a concurrent review of the available Phase 3 COVE study safety data by the Data Safety Monitoring Board (DSMB), which did not report any significant safety concerns, the company said. A review of solicited adverse events indicated that the vaccine was generally well tolerated. The majority of adverse events were mild or moderate in severity. Grade 3 (severe) events greater than or equal to 2 percent in frequency after the first dose included injection site pain, and after the second dose included fatigue, myalgia, arthralgia, headache, pain, and erythema/redness at the injection site. These solicited adverse events were generally short-lived, the company said.

These data are subject to change based on ongoing analysis of further Phase 3 COVE study data and final analysis, according to the announcement. Preliminary analysis suggests a broadly consistent safety and efficacy profile across all evaluated subgroups.

As more cases accrue leading up to the final analysis, Moderna representatives said they expect the point estimate for vaccine efficacy may change. Additionally, they said the company plans to submit data from the full Phase 3 COVE study to a peer-reviewed publication.

A week ago, competitor pharmaceutical giants Pfizer and BioNTech announced its vaccine candidate was found to be more than 90 percent effective in preventing COVID-19. Experts say both companies are on track to seek emergency use authorization from the U.S.  Food and Drug Administration (FDA) within weeks.

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