An overview of a new study in adults showing the Abrysvo respiratory syncytial virus (RSV) vaccine preventing lower respiratory tract disease (LRTD) caused by RSV infection among older adults, a group at high risk of severe disease.
The study’s setup
The RSV vaccine RSVpreF (Abrysvo) was evaluated using a test-negative control design in a high-risk general older clinical population (>60 years of age) with an LRTD episode requiring hospitalisation or an emergency department (ED) visit.[1]
Two control groups were defined:
- “Strict”. LRTD testing negative for vaccine-preventable disease VPD) due to RSV, HMPV (just in case the vaccine produces cross-protection, SARS-CoV-2 and positive for non-VPD pathogens.
- Broad. RSV-negative regardless of detecting another microbial cause.
Key findings
The Abrysvo vaccine effectiveness (VE) using Strict controls was 91%, and using Broad controls was 90%, which closely agrees with a previous smaller study (RENOIR; [2]). The authors note that this new report better represents the severe end of disease in older adults, which is really where the vaccine aims to have a positive impact.
Using this VE, the authors calculated that one severe outcome could be prevented for every 250 vaccinated people in the first season after vaccination. Of the 280,000 severe cases annually, 1,120 could be prevented in older adults, preventing harm and feeding up expensive ED beds and resources.
How immunity wanes over time remains to be seen, but this is a great start to provide a safe immunity boost in older adults. I say ‘boost’ because we all get RSV infection by two years of age. Despite this and repeated exposures throughout life (especially once we’re the parents of young kids!), the aging immune system needs help remembering this.
A safe RSV vaccine boost is much better than a potential hospital visit due to a natural infection.
References
- Estimated Vaccine Effectiveness for Respiratory Syncytial Virus–Related Lower Respiratory Tract Disease
https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2828028 - Efficacy and safety of a bivalent RSV prefusion F vaccine in older adults
https://www.nejm.org/doi/10.1056/NEJMoa2213836?url_ver=Z39.88-2003 - https://www.immunize.org/clinical/image-library/vaccination/