RSV Vaccine 90% Effective in High-Risk Adults, Real-World Study Shows

The bivalent RSV prefusion F vaccine (Abrysvo) demonstrated 90% vaccine effectiveness (VE) in high-risk adults against hospitalizations or emergency department (ED) visits associated with respiratory syncytial virus (RSV), according to recent real-world data presented at the IDWeek annual meeting in Los Angeles.

In this exclusive MedPage Today video, Sara Tartof, PhD, MPH, of Kaiser Permanente in Pasadena, California, discusses the key findings and the importance of real-world effectiveness in supporting current vaccine recommendations for high-risk populations.

Following is a transcript of her remarks:

The key findings from the study were that we estimate 90% real-world VE of Abrysvo during the first 5 months of use against severe ARI [acute respiratory infection] in hospital or ED settings among U.S. adults age 60 and older.

I think what makes this study particularly important at this time is that our real-world study included substantially more people at risk for severe RSV, including older adults, immunocompromised adults, and adults with overall greater burden of comorbidities compared with the clinical trial RENOIR. And as we know, clinical trials tend to have much more controlled study populations, and I think what we found in this study is that the VE, even in real-world use, was quite high.

For RSV in particular, one of the main challenges for research is low standard of care testing in healthcare settings as opposed to something like COVID or flu, which is tested much more frequently. RSV testing can sometimes be in certain settings. For example, in our setting, RSV testing is restricted in older populations, so the hospital setting using a multiplex panel.

One way that we mitigated the effects of this kind of limited testing was by salvaging swabs that were used for COVID or flu tests. We then tested those swabs for RSV using that same multiplex panel that was used for standard of care. So that was just one way we overcame one of the main what I feel are challenges to RSV research.

Another challenge that we found in the first season was overall fairly low uptake of the vaccine. I think what we anticipate in the second season — given the new recommendations that I think are a little more clear compared to shared clinical decision-making, which can be a little bit complex for providers and difficult to implement — is we do anticipate higher vaccine uptakes. So not only will we have more years to evaluate, but I am anticipating that more patients will be vaccinated.

We didn’t specifically stratify our analysis by immunocompromised patients. We didn’t have the statistical power at this time, but I think we are able to make some comment on the effectiveness of the vaccine on immunocompromised patients, just given that 16% of our population was immunocompromised and 76% of our population had a Charlson index score of 3 or more. So we did have a very clinically high-risk population and we still found these high VE estimates. But again, as seasons go on, as we’re able to accrue more numbers, our statistical power will increase and we do hope to analyze VE for specifically immunocompromised populations.

These findings really support current recommendations. I mean, the recommendations at this time are for high-risk populations, and what we found is that the vaccine appears effective in these high-risk populations. So I think that’s also really important to have these real-world data that support current recommendations, particularly for new vaccine products.

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