Early trial results hail Moderna's COVID-19 vaccine as 94.5% effective

Data also show that mRNA-1273 remains stable at 2–8°, the temperature of a standard home or medical refrigerator, for 30 days.

The US biotechnology company's vaccine, mRNA-1273, which is going through a Phase III clinical trial (COVE), has met the statistical criteria pre-specified in the study protocol for efficacy, with a vaccine efficacy of 94.5%.

The study enrolled more than 30,000 participants in the US, including communities that have historically been under-represented in clinical research and have been disproportionately affected by COVID-19. Half of the participants received a placebo, whereas the other half received two doses of the vaccine candidate.

The primary endpoint of the Phase III study (the prevention of symptomatic COVID-19 disease) is based on the analysis of COVID-19 cases confirmed and adjudicated starting 2 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 5 cases observed in the mRNA-1273 group, resulting in a point estimate of vaccine efficacy of 94.5%.

A secondary endpoint (prevention of severe COVID-19 disease) analysed severe cases of COVID-19 and included 11 severe cases in this first interim analysis. All 11 cases occurred in the placebo group and none in the mRNA-1273 vaccinated group.

Stéphane Bancel, Chief Executive Officer of Moderna, described the event as a "pivotal moment" in their effort to develop a safe and efficacious COVID-19 vaccine.

Unlike the Pfizer vaccine candidate, which has logistical challenges — it needs to be stored at about -70 °C — Moderna's vaccine remains stable at 2–8 °C, the temperature of a standard home or medical refrigerator, for 30 days. Furthermore, mRNA-1273 remains stable at -20 °C for up to 6 months, at refrigerated conditions for up to 30 days and at room temperature for up to 12 hours.

Although the trial will continue to accrue additional data relevant to safety and efficacy, the company intends to submit for an Emergency Use Authorization (EUA) with the US FDA in the coming weeks.

Pending approval, Moderna expects to have approximately 20 million doses of mRNA-1273 ready to ship in the US by the end of 2020 and remains on track to manufacture 500 million to 1 billion doses globally in 2021.