In a letter published in the New England Journal of Medicine, Moderna has reported that participants in the Phase I study its mRNA-1273 COVID-19 vaccine candidate, retained high levels of neutralising antibodies for 119 days following first vaccination (90 days following second vaccination).
The study was led by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH).
Author Alicia Widge MD of Vaccine Research Center, NIAID, NIH and others summarised that “mRNA-1273 produced high levels of binding and neutralising antibodies that declined slightly over time, as expected, but they remained elevated in all participants three months after the booster vaccination.”
These results were consistent across all age groups (18-55, 56-70 and 71+). The authors continued: “Although correlates of protection against SARS-CoV-2 infection in humans are not yet established, these results show that despite a slight expected decline in titres of binding and neutralising antibodies, mRNA-1273 has the potential to provide durable humoral immunity.”
They also reported that, “No serious adverse events were noted in the trial, no prespecified trial-halting rules were met, and no new adverse events that were considered by the investigators to be related to the vaccine occurred after day 57.” The full letter and associated data are available here.
“These interim Phase I data suggests that mRNA-1273, our COVID-19 vaccine candidate can generate durable neutralising antibodies across all age groups including in older and elderly adults. Live virus and pseudovirus assay geometric mean titers (GMTs) remain high in the first months following vaccination,” said Tal Zaks, Chief Medical Officer of Moderna. “These data give us further optimism to expect that the high level of efficacy recently demonstrated by mRNA-1273 to prevent COVID-19 disease will be durable.”
Moderna has re-affirmed its expectation of having approximately 20 million doses available in the US. by the end of 2020. Additionally, the company expects to have between 100 million and 125 million doses available globally in the first quarter of 2021, with 85-100 million of those available in the US. and 15-25 million of those available outside of the US.
These expected first quarter doses are inclusive within the 500 million to up to 1 billion doses that the Company expects to manufacture globally in 2021.
This announcement follows the company’s November 30 announcement that the primary efficacy analysis of the Phase III study of mRNA-1273 conducted on 196 cases confirmed the high efficacy observed at the first interim analysis. The data analysis indicates a vaccine efficacy of 94.1%.