— Moderna's RSV Vaccine Approved for Adults 60 and Over

The FDA has given the green light to Moderna's mRNA-1345 vaccine (also known as mRESVIA), aimed at protecting adults aged 60 and older from respiratory syncytial virus (RSV) and its related lower respiratory tract diseases, Moderna declared in a press release on Friday.

“This FDA approval represents a significant milestone that highlights the adaptability and strength of our mRNA technology,” said Stéphane Bancel, Moderna's CEO, adding that it's the first instance of an mRNA-based vaccine being cleared for anything other than COVID-19.

With this approval, the mRNA-1345 vaccine becomes the second product Moderna offers, alongside their SARS-CoV-2 mRNA-1273 (often branded as Spikevax).

The FDA’s decision was based on results drawn from the phase III ConquerRSV study. The trial included approximately 37,000 participants, all aged 60 and above. Findings revealed the vaccine to be 83.7% effective (95.88% CI, 66%-92.2%) in fending off RSV-associated lower respiratory tract disease featuring two or more symptoms. Its effectiveness was also noted to be 82.4% (96.36% CI, 34.8%-95.3%) in cases involving at least three symptoms.

Adverse reactions were more noticeable in those receiving the vaccine compared to the placebo group (47.7% vs 32.9%). More frequent side effects included fatigue, headaches, muscle aches (myalgia), and joint pain (arthralgia). Serious side effects manifested in 2.8% of participants from both the vaccine and placebo groups. However, the majority of these reactions were short-lived and categorized as mild to moderate, with under 0.1% of side effects being directly attributed to the vaccine.

During the FDA's review, a follow-up analysis echoed the original results, confirming the vaccine's effectiveness for the study’s primary outcome. Furthermore, extended analysis demonstrated ongoing protection against lower respiratory tract infections caused by RSV, with coverage extending over a median span of 8.6 months.

Per Moderna’s announcement, the mRNA-1345 vaccine is slated to be available in the U.S. for the 2024-2025 respiratory virus season. It is expected to come in prefilled syringes to simplify administration and lower the risks of dosing errors.

The vaccine is composed of an mRNA sequence designed to prompt the production of a stabilized version of the prefusion F glycoprotein. This glycoprotein serves as a main target for neutralizing antibodies and is consistent across both RSV subtypes, RSV-A and RSV-B. Notably, the vaccine employs the same lipid nanoparticle delivery system as Moderna's mRNA-1273 vaccine.

Earlier in 2023, the FDA had also approved two other vaccines for RSV, though they were not mRNA-based: Pfizer’s Abrysvo and GSK’s Arexvy. Pfizer’s vaccine has the added approval for use in pregnant individuals, aimed at safeguarding infants from RSV after birth.