mRNA Flu Vaccine Shows Higher Efficacy in Adults 50 and Older

A study published in the New England Journal of Medicine reported that the mRNA-1010 influenza vaccine lowered the incidence of confirmed influenza-like illness in adults aged 50 and older compared with standard-dose licensed vaccines. The trial observed illness in 2.0% of mRNA-1010 recipients versus 2.8% of those receiving the comparator, indicating a relative vaccine efficacy of 26.6% (95% CI, 16.7 to 35.4). In participants 65 and older, efficacy was slightly higher at 27.4%.

"mRNA-1010 was superior to standard-dose licensed vaccines for prevention of RT-PCR–confirmed, protocol-defined influenza-like illness in adults 50 years of age or older," the authors concluded.

Deborah Fuller, PhD, a professor of microbiology at the University of Washington School of Medicine, emphasized the seriousness of flu in older adults, noting that comorbidities such as heart disease, kidney disease and diabetes increase mortality risk. She explained that aging-related immunosenescence reduces vaccine responsiveness, making higher efficacy especially valuable.

Fuller, who has long studied mRNA and DNA vaccines, said the current generation of mRNA flu shots can generate antibodies against a broader range of influenza strains and also stimulate cellular immunity. She added that mRNA platforms allow manufacturers to begin production three to four months after strain selection, compared with eight to nine months for traditional vaccines.

Addressing lingering hesitancy, Fuller argued that mRNA technology is not new, having been under development for more than three decades, and that billions of doses have been administered since 2020 with extensive safety monitoring. She clarified that mRNA vaccines do not alter DNA, describing them as short-lived instructions that the body degrades within hours or days.