Moderna: Vaccine Shown Effective Against RSV in Older Adults in Phase III Trial

On January 17, 2023, Moderna announced its investigational, mRNA-based vaccine proved effective in protecting against the respiratory syncytial virus (RSV) in older adults with no safety concerns.

RSV is a common and contagious respiratory virus that attacks the lungs and breathing passageways. Currently, there is no targeted treatment or vaccine for children or adults, but there are several in trials. Older adults are at high risk of severe disease progression due to a natural age-related decline in immunity. RSV is responsible for an estimated 420,000 hospitalizations and 29,000 deaths in industrialized nations.

“It is exciting to see the possibility of adding RSV to the list of vaccine-preventable diseases for older adults,” Shannon Simmons, DHSc, MPH, CIC, a system infection preventionist for CHRISTUS Health in Irving, TX, told Infection Control Today^®. “The reported efficacy of the Moderna investigational mRNA vaccine targeting RSV in older adults has the ability to provide protection for a segment of the population that is increasingly vulnerable but often disregarded. We saw firsthand how older adults were disproportionately impacted by COVID-19, so it’s extremely important that all older adults consider the advantages of a vaccine aimed at preventing lower respiratory disease."

The data evaluated the efficiency of Moderna’s RSV vaccine, mRNA-1345, in protecting older adults. The investigators created 2 groups of 64 cases: one group had 2 or more symptoms, and the other had 3 or more symptoms of RSV-associated lower respiratory tract disease (RSV-LRTD).

The investigators identified no safety concerns with the vaccine, which was well tolerated. The most common adverse reactions noted were injection site pain, myalgia, arthralgia, fatigue, and headache.

For this Moderna trial, the group of 2 or more symptoms met the endpoint first and showed that the vaccine was 83.7% effective. The group with 3 or more symptoms then met the endpoint and showed that the vaccine was 82.4% effective.

The investigators identified no safety concerns with the vaccine, which was well tolerated. The most common adverse reactions noted were injection site pain, myalgia, arthralgia, fatigue, and headache.

This trial, called the ConquerRSV trial, was a randomized, double-blind, placebo-controlled study, and it evaluated mRNA-1345 in approximately 37,000 adults aged 60 years or older in 22 countries, including the US.

The interim analysis was based on 64 cases of RSV-LRTD with 2 or more symptoms. The placebo group had 55 cases, and the mRNA-1345 group had 9. There were 20 cases of RSV-LRTD with 3 or more symptoms. The placebo group contained 17 cases, and the mRNA-1345 group had 3 cases.

Because of these encouraging results of preventing severe lower respiratory disease due to RSV in the older population, Moderna intends to submit for regulatory approval in the first half of 2023. The data will be submitted to a peer-reviewed publication and presented at an upcoming scientific meeting.

The mRNA-1345 vaccine is being tested in an ongoing Phase 1 trial in pediatric populations, and the clinical trial is fully enrolled.

This announcement comes 2 months after Pfizer announced encouraging data on an RSV vaccine for pregnant persons. In October 2022, GSK also announced that its RSV vaccine trial demonstrated promising results for older adults.