Moderna SARS-CoV-2 Vaccine Elicits Response in Older Adults

A small phase 1 study of 40 adults over age 56 years found that Moderna’s 2-shot mRNA-1273 vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) showed binding antibody responses similar to those previously reported in younger adults.

The study is part of Moderna’s larger trial to find a vaccine to prevent SARS-CoV-2 from causing coronavirus disease 2019, which puts older adults, who have weaker immune responses, at a higher risk of more severe illness and death.

The results, which were published Tuesday in The New England Journal of Medicine, also found that the response following the second dose was similar to those in patients who were infected, recovered, and donated convalescent plasma.

The most powerful effect was seen in the 100-mcg dose, which is being tested in a phase 3 study, enrolling 30,000 adults, that began at the end of July.

The study is being conducted in 3 centers—Kaiser Permanente Washington Health Research Institute, the Emory University School of Medicine, and the National Institute of Allergy and Infectious Diseases Vaccine Research Center.

In this trial of older adults, 2 subgroups of 40 adults (nearly all White) were stratified by age 56 to 70 years or 71 years and older; they received 2 doses 28 days apart of either 25 mcg or 100 mcg.

By day 57, the geometric mean titer (GMT), or measure of antibody response, for patients who received the 100-mcg dose was 1,183,066 for those aged 56 to 70 years; GMT reached 3,638,522 for those 71 years and older.

By comparison, the GMTs for the 25-mcg dose were 323,945 and 1,128,391 in the same 2 age groups, respectively.

Titers rapidly increased by 7 days after the second dose, the authors said.

The findings also show “strong correlations” between the receptor-binding enzyme-linked immunosorbent assay and all neutralization assays, which may indicate that the reference values might “assess immunogenicity of SARS-CoV-2 vaccines and potentially to confirm an immunologic correlate of protection that would support public-health decision making regarding vaccination strategies,” the authors wrote.

Adverse events, which were dose dependent and were more commonly seen after the second immunization, were mostly mild and moderate, including fatigue, chills, headache, myalgia, and pain at the injection site.

The Moderna candidate is 1 of 11 SARS-CoV-2 vaccines in the later stages of testing.

Separately this week, the FDA told another company, Inovio Pharmaceuticals, to delay its final trials of its vaccine candidate; the FDA wants more information about the details of a delivery device used to inject genetic material into cells. It is the second delay for the start of the trial, which was slated to begin in the summer, Reuters reported.

Reference

Anderson EJ, Rouphael NG, Widge AT, et al. Safety and immunogenicity of SARS-CoV-2 mRNA-1273 vaccine in older adults. N Engl J Med. Published online September 29, 2020. doi:10.1056/nejmoa2028436