A Dose of Knowledge: The Importance of the Long-Awaited RSV Vaccine

Written by: Sudil Mahendra, Scientific Director

The theme of World Immunization Week 2023 is “The Big Catch-Up,” which is fitting given that many children and adults missed out on vaccinations during the global SARS-CoV-2 pandemic.1 However, the theme is also relevant to a new set of vaccines against respiratory syncytial virus, or RSV, that are primed for approval in the coming months. These vaccines will provide protection against a virus that has eluded the best efforts of researchers for over 50 years.

These vaccines will provide protection against a virus that has eluded the best efforts of researchers for over 50 years.

THE LEADING CAUSE OF SEVERE RESPIRATORY INFECTIONS

RSV is one of the lesser-known viruses that cause respiratory infections. It is highly contagious and has similar symptoms to influenza. It was first described in 1956 as a cause of infant pneumonia.2 However, RSV is one of the leading causes of severe respiratory illnesses in both young children and older adults.
Each year in the United States, RSV infections result in hospitalizations of approximately 57,000 children under the age of 5. And while RSV may be known to some as a cause of severe infection in infants, the potential impact to older adults and adults with compromised immune systems is also of great importance. Annually, RSV is estimated to cause hospitalization of 60,000 to 120,000 adults 65 years of age and older in the U.S.3  

For these vulnerable groups, it’s crucial that the risks of RSV infection are understood and preventative measures, such as vaccination, are taken.

SIMILAR RISKS OF RSV VS INFLUENZA INFECTION IN OLDER ADULTS

Data regarding clinical outcomes of severe infections due to RSV in older adults are limited, which makes detailing the risk of RSV infection difficult. However, clinical outcomes of severe infection due to influenza can serve as an effective example, as influenza is well-studied. In the recent months, two publications have expanded the available data comparing clinical outcomes of RSV and influenza.

The first study reviewed several studies with patients 60 years of age or older from several countries and determined incidence rates of hospitalization and mortality in patients with either RSV or influenza. Results showed that both the cumulative incidence during the study and the incidence rate of hospitalization and mortality was similar between RSV and influenza.4  
The second study included over 10,000 adults (~78% over the age of 50) in the United States who were hospitalized for acute respiratory infection and tested for RSV and influenza. Over 50% of all RSV cases in this study were among adults ≥65 years of age. This study showed that adults with RSV had higher odds of extended stay in the hospital (8 days or longer) and were more likely to need for assisted ventilation (assisted breathing) compared with those with influenza.5  

The results of both studies demonstrate the importance of RSV vaccines for older adults.

THE WINDING PATH TO AN RSV VACCINE

Although there are now RSV vaccine candidates under review by the U.S. Food and Drug Administration (FDA), it has been a long journey to this milestone. In 1966, an inactivated, or “killed,” vaccine candidate increased the likelihood of hospitalization after infection. Another vaccine candidate that utilized the RSV surface protein, known as F, again failed to provide protection.

In 2013, researchers at the U.S. National Institute of Allergy and Infectious Diseases determined that the shape that the F protein formed while it was fusing with host cells was crucial in designing an effective vaccine.6 The F protein rearranges when the virus fuses with a cell, so researchers designed a strategy to lock it in its “prefusion” form, which is sensitive to attack by antibodies. This technique was also used to isolate the most optimal form of SARS-CoV-2 surface protein for antibody response and vaccine development.

In 2023, vaccine development technology is finally catching up to RSV, as it did for influenza and SARS-CoV-2. Three different RSV vaccines for older adults are expected to be approved this year, thanks to decades of research and development.

Finally, some of the most vulnerable individuals will have protection against severe respiratory illness caused by RSV.

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At Razorfish Health, we know what it takes to navigate the modern health care landscape. If you want to fuel your knowledge, please reach out to Delia.Pavlichko@razorfishhealth.com. We’re interested in hearing your perspective, as well as your thoughts, on the upcoming communication challenges and opportunities.

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References:

  1. World Health Organization. World Immunization Week 2023. Accessed April 24, 2023. https://www.who.int/campaigns/world-immunization-week/2023

  2. National Institute of Allergy and Infectious Diseases. U.S. Department of Health and Human Services. Experimental respiratory syncytial virus vaccine prompts antibody surge. August 1, 2019. Accessed April 25, 2023. https://www.niaid.nih.gov/news-events/experimental-respiratory-syncytial-virus-vaccine-prompts-antibody-surge

  3. Talbot HK, Belongia EA, Walsh EE, Schaffner W. Respiratory syncytial virus in older adults: a hidden annual epidemic. Infect Dis Clin Pract. 2016;24(6):295-302.

  4. Maggi S, Veronese N, Burgio M, et al. Rate of hospitalizations and mortality of respiratory syncytial virus infection compared to influenza in older people: a systematic review and meta-analysis. Vaccines (Basel). 2022;10(12):2092. doi:10.3390/vaccines10122092

  5. Begley KM, Monto AS, Lamerato LE, et al. Prevalence and clinical outcomes of respiratory syncytial virus versus influenza in adults hospitalized with acute respiratory Illness from a prospective multicenter study [published online ahead of print, 2023 Jan 24]. Clin Infect Dis. 2023;ciad031. doi:10.1093/cid/ciad031

  6. McLellan JS, Ray WC, Peeples ME. Structure and function of respiratory syncytial virus surface glycoproteins. Curr Top Microbiol Immunol. 2013;372:83-104. doi: 10.1007/978-3-642-38919-1_4

Nina Rupp