- Moderna on Tuesday reported positive results for its experimental respiratory syncytial virus vaccine, saying the shot was about 84% effective in preventing lower respiratory tract disease among older adults in a large, late-stage trial.
- Moderna’s candidate is one of at least six in a race among drugmakers to develop an RSV vaccine, development fueled by research progress in identifying a better way to stimulate an immune response against the virus. GSK and Pfizer have both already asked the Food and Drug Administration to approve their RSV vaccine candidates for adults over the age of 60, with decisions expected this year.
- Moderna’s Phase 3 trial measured how well the vaccine prevented at least two symptoms of RSV-associated respiratory infection in adults older than 60. Moderna plans to ask for approval in the first half of the year, putting a spotlight on how its candidate compares to the other would-be shots.
RSV is a common respiratory infection that typically occurs during the colder months. The infection can be particularly dangerous in children younger than 5 and in adults over the age of 65. According to the Centers for Disease Control and Prevention, between 100 and 300 children under 5 and between 6,000 to 10,000 older adults die each year from RSV infections.
Scientists have tried to develop an RSV vaccine for years, but only recently have those research efforts led to clinical successes. Along with GSK, Pfizer and Moderna, Johnson & Johnson, Sanofi and Bavarian Nordic are also testing RSV vaccines.
GSK had previously set a high bar with results from a Phase 3 trial that showed its vaccine reduced cases of lower respiratory infection by 83% in adults over the age of 60 compared to a placebo. The results were announced in October 2022, several months after Pfizer had revealed preliminary data for its RSV vaccine. While efficacy versus severe disease was 86%, Pfizer’s data showed somewhat lower efficacy of 67% when measured using a broader case definition.
Direct comparisons across clinical trials can be difficult, however, as differences in design and enrolled population may influence how results appear.
Moderna said its vaccine was well tolerated, with most reactions rated either mild or moderate. The most commonly reported included injection site pain, joint stiffness, headache, fatigue and muscle aches. Safety will continue to be monitored as the study progresses.
The biotech company plans to submit the data for publication in a peer-reviewed journal and will present it at a scientific meeting.
Vaccine developers, including Pfizer, are also testing RSV vaccines for use in pregnant women to protect infants.
An antibody treatment from Sanofi and AstraZeneca, meanwhile, is currently under review by the FDA and was recently cleared in Europe for the prevention of the disease in infants.