Moderna’s mRNA-1273 vaccine against COVID-19 showed 95% vaccine effectiveness in an interim analysis performed after 95 participants developed the illness, a press release from the manufacturer said on Monday.
An independent NIH-appointed data safety and monitoring board found that interim data from the 30,000-person COVE study showed 95 cases of COVID-19 — 90 in the placebo group and five in the vaccine group — for a vaccine efficacy of 94.5% (P<0.001). This study was conducted in collaboration with the National Institute of Allergy and Infectious Diseases (NIAID) and the Biomedical Advanced Research and Development Authority (BARDA).
The vaccine also showed efficacy against severe disease, with 11 cases in the placebo arm versus zero among those vaccinated.
“This has been a week of dramatic contrasts in COVID-19,” said NIH director Francis Collins, MD, on a press call. Officials attempted to strike a balance between optimism about the vaccine against the backdrop of a surging pandemic across the U.S. that just passed 11 million cases.
He noted that this was the second time a vaccine showed promising efficacy, with similar positive interim results from Pfizer’s mRNA vaccine candidate released a week ago.
Anthony Fauci, MD, director of NIAID, characterized the interim results as “truly striking.” He said they resolved a lot of uncertainties about the mRNA platform, which had never been used for an approved vaccine before, and whether the vaccine could prevent severe disease. But now “all the boxes have been checked,” he said.
Fauci recalled a NIH press briefing in July when Moderna started their phase III trial and telling reporters that he would be satisfied with 70%-75% efficacy for a COVID-19 vaccine, but 90% was more of an “aspirational” target.
“Well, our aspirations have been met,” Fauci said, describing a safe and effective vaccine against COVID-19 as “the light at the end of the tunnel.”
Collins emphasized the diversity of the study, with 37% of the group comprised of “people of racial or ethnic diversity.” Moderna president Stephen Hoge, MD, added that researchers did work to enrich the study population for people at high risk, noting 25% were adults over age 65 and 17% were adults under age 65, but with comorbidities that put them at high risk for severe COVID-19, such as obesity, high blood pressure, and diabetes.
All told, about 42% of the study population were adults at high risk of severe COVID-19, he said.
Fauci also emphasized not to underestimate the importance of biomedical research in this process, noting that research confirmed the spike protein as the critical immunogen and allowed researchers to “get this right using advances in structural biology.”
All vaccine platforms in Operation Warp Speed (OWS) — mRNA, vector expression of the spike protein gene, and the soluble protein — all use spike protein as the target immunogen, Fauci said.
“If that is the case, and it holds true, we now have shown with two vaccines that the immune response against the spike protein is a protective response. Conceptually, this looks good and it looks like we’re on firm ground for continued positive results coming in because of the immunogen involved,” he added.
The vaccine will also be able to be stored in a refrigerator for a month, Moderna CEO Stéphane Bancel, MBA, confirmed on the call. In separate press release Monday, the company said the product can be kept at 2° to 8°C — far easier to maintain than the -70°C needed for Pfizer’s competing vaccine.
Bancel also reiterated that Moderna is “working hard” to have 20 million doses at the end of the year, but they hope to increase their output every month, with the goal of 500 million to 1 billion doses in 2021.
OWS lead Matt Hepburn, MD, said that storage of the Moderna vaccine “enables a much more distributed model to get the vaccine out there in very rural areas” and makes the process as convenient as possible for Americans who need it.
Moderna said in its release that the 95 cases included 15 adults ages 65 and older, 12 Hispanics, four Black individuals, three Asian Americans, and one multiracial individual.
The vaccine was generally well tolerated, with the majority of adverse events being mild or moderate. The most common grade 3 adverse events were fatigue (9.7%), myalgia (8.9%), and arthralgia (5.2%). Hoge said adverse events were “generally consistent” with phase I results, although data analysis is ongoing.
Next steps would be to apply for emergency use authorization from the FDA, and present these results in front of an FDA advisory panel, which should happen “in the coming weeks,” Moderna said in their release.