Moderna: COVID-19 Vaccine Shows Promising Immune Response Results in Phase 1 Study

July 15, 2020

Moderna's vaccine candidate was found to induce a high neutralizing antibody response in all study participants.

Biotechnology company Moderna published interim results from the Phase 1 study of their coronavirus disease 2019 (COVID-19) vaccine that showed the vaccine candidate induced high neutralizing antibody response in all participants.

In a statement to the Associated Press, Anthony Fauci, MD, expressed optimism about the novel vaccine (messenger RNA [mRNA]-1273) that was co-developed by his colleagues at the National Institutes of Health:

"No matter how you slice this, this is good news . . . We need multiple vaccines. We need vaccines for the world, not only for our own country.”

The study – published July 14, 2020 in the New England Journal of Medicineevaluated a 2-dose vaccination schedule of mRNA-1273, given 28 days apart across 3 dose levels (25, 100, and 250 μg) in 45 healthy adults aged 18-55 years between March 16 and April 14, 2020.

The results reaffirmed and expanded upon the positive interim data announced in May, and found that after the first vaccination, antibody responses were higher in those who received higher doses of mRNA-1273. These antibodies increased after the second dose of mRNA-1273.

Fatigue, chills, headache, myalgia, and pain at the injection site occurred in over 50% of participants following the second vaccination, but all of those adverse events were transient and mild or moderate in severity.

“These Phase 1 data demonstrate that vaccination with mRNA-1273 elicits a robust immune response across all dose levels and clearly support the choice of 100 µg in a prime and boost regimen as the optimal dose for the Phase 3 study,” said Tal Zaks, MD, PhD, chief medical officer, Moderna, Cambridge, Massachusetts, in a company press release. “We look forward to beginning our Phase 3 study of mRNA-1273 this month to demonstrate our vaccine’s ability to significantly reduce the risk of COVID-19 disease.”

Enrollment for Phase 3 is set to begin July 27, 2020 and will include approximately 30 000 participants to further evaluate if mRNA-1273 will protect against COVID-19.