Moderna says RSV vaccine 84% effective at preventing symptoms in older adults

Moderna Inc said on Tuesday that its experimental messenger RNA vaccine for respiratory syncytial virus (RSV) was 83.7 per cent effective in a late-stage trial at preventing at least two symptoms, such as cough and fever, in adults aged 60 and older.

RSV, which produces symptoms similar to a cold but can be fatal for young children and older adults, causes about 14,000 deaths annually in adults ages 65 and older. The disease surged in the United States and Europe this fall alongside the flu and COVID-19.

There is currently no vaccine for the virus in adults. Moderna, Pfizer Inc and GSK Plc are racing to get their RSV vaccines to market first.

Pfizer and GSK filed applications for U.S. regulatory approval late last year. Pfizer's RSV vaccine was found to be 66.7 per cent effective against two or more symptoms in late-stage trials.

Moderna said it intends to submit its vaccine, mRNA-1345, for regulatory approval consideration globally in the first half of 2023.

'It's very exciting to see progress'

Moderna president Stephen Hoge told Reuters its vaccine appears to compare favourably to the experimental Pfizer and GSK shots.

"It's very exciting to see progress in RSV vaccines in older adults, and I think both of those vaccines have shown pretty remarkable results as well," Hoge said. "We really think we're in that top class — 84 per cent is a terrific efficacy number."

The RSV vaccine market could be worth more than $10 billion US globally, half of which would come from the United States, according to Cowen analyst Tyler Van Buren.

Moderna's study was conducted in about 37,000 participants aged 60 years and older. The data analysis was performed after 64 participants contracted RSV. The company plans to release the full data at a medical meeting.

Hoge said Moderna had started secondary analysis on the vaccine's efficacy against more severe disease and hospitalization. He said it was too early to provide a potential price range for the vaccine it expects to be given annually.

The vaccine was generally found to be safe, with the most common side effects including injection site pain, fatigue and headache. Hoge said there were no myocarditis concerns — a type of heart inflammation linked to mRNA COVID vaccines.