Back Again: Vaccines for RSV Near Approval

Although well known to clinicians, respiratory syncytial virus (RSV) has until recently gone largely unnoticed by the public. Media attention to a “tripledemic”—of COVID-19, influenza, and RSV infection—during the 2022- 2023 respiratory virus season may have temporarily changed that, however, and now RSV is back in the news due to the approval of vaccines to prevent negative outcomes from RSV in young children and elderly patients.

Even before the pandemic focused our collective attention on viral pneumonia, molecular diagnostic modalities were helping to expose the magnitude of the problem caused by viral pathogens. Viruses, not bacteria, are the most commonly identified cause of community-acquired pneumonia (CAP) in children and adults,^1,2 and RSV specifically is the most common pathogen in pediatric CAP. Standard of care is to administer antibacterials to nearly all patients with CAP, but those agents are not helping the large percentage of patients with nonbacterial infections. With the exception of influenza and COVID- 19, there is not much that can be done to treat infections caused by respiratory viruses.

RSV vaccination has travelled a bumpy road. A vaccine candidate in the 1960s failed spectacularly: outcomes in infants who received it were much worse than in those who did not, and development was essentially suspended for decades.³ Advances in the structural targeting of vaccines have moved the field forward, and in 2022 FDA submissions were filed for multiple vaccines. The FDA Vaccine and Related Biological Products Advisory Committee (VRBPAC) met this February and March to consider vaccines from Pfizer and GSK, approving both for adults aged 60 years and older. Those for young children are not as advanced in development but are also in the pipeline. Closer to approval are vaccines for pregnant women, who pass on the benefit of vaccination to infants.⁴

Of course, challenges will arise from the introduction of vaccines for a virus with which most people are unfamiliar. The limited uptake of COVID-19 vaccines among children shows that many parents are still hesitant, even when a widespread pathogen receives constant media attention. Also, since immunity from RSV infection or vaccination is temporary and infection is essentially universal, educating people about what vaccines do—protect against serious disease but not against infection—will be important. Obstacles aside, if successful, RSV vaccines are an advance. The burden of this disease is quite high, and it is reassuring to see that successful vaccines may be available in an area that had once been abandoned.

References

1. Jain S, Self WH, Wunderink RG, et al. Community-acquired pneumonia requiring hospitalization among U.S. adults. N Engl J Med. 2015;373(5):415-427. doi:10.1056/NEJMoa1500245

2. Jain S, Williams DJ, Arnold SR, et al. Community-acquired pneumonia requiring hospitalization among U.S. children. N Engl J Med. 2015;372(9):835-845. doi:10.1056/NEJMoa1405870

3. Abbasi J. RSV vaccines, finally within reach, could prevent tens of thousands of yearly deaths. JAMA. 2022;327(3):204-206. doi:10.1001/jama.2021.23772

4. Cohen, J. Extremely satisfying’: Scientist’s insight powers new RSV vaccine for infants. Science. November 2, 2022. https://www.science.org/content/article/extremely-satisfying-scientists-insight-powers-new-rsv-vaccine-infants