There are currently 33 RSV prevention candidates in clinical development using 6 different approaches.
Nearly all children are infected with respiratory syncytial virus (RSV) before their second birthday.1 Repeat infections of RSV can affect people of all ages with mild, cold-like symptoms such as fever, cough, and rhinorrhea. However, it can lead to serious illness and potentially death in infants and older adults.1
Across the nation, RSV cases are elevated this year, highlighting the fact that an RSV vaccine is not yet on the market.2
In January 2023, The Lancet Infectious Diseases published a review of RSV vaccines and monoclonal antibodies currently in clinical development and highlighted the different target populations, antigens, and trial results. The researchers found that 33 RSV prevention candidates are in clinical development using 6 different approaches: recombinant vector, subunit, live-attenuated, chimeric, particle-based, and nucleic acid vaccines; and monoclonal antibodies. Nine of these candidates are in phase 3 clinical trials.
Live-attenuated vaccines are currently in development for infants older than 6 months of age. Subunit vaccines for pregnant women are in late-stage trials to protect infants. Vector, subunit, and nucleic acid vaccines are being developed for older adults.
Monoclonal antibodies (mAbs) are expected to protect premature and full-term infants. Maternal vaccination provides broader protection and a backup in the event of viral resistance to mAbs, or high costs related to the production of biologics that limit administration. However, pediatric immunization will still serve an important role because acquired antibodies from maternal immunization or mAb immunoprophylaxis will wane over time.
With multiple RSV vaccines on the horizon, several candidates could be approved, therefore cost and delivery strategies may determine vaccine uptake for maternal and older adult candidates. Even with the potential approval of several RSV vaccines, obstacles to worldwide access remain.
Measuring protection and monitoring viral resistance remains a challenge in many low- to middle-income countries. Additionally, vaccine trials with global representation must be completed because efficacy can differ between countries.
New RSV prevention candidates are within reach and have the potential to decrease RSV cases, costs, and mortality worldwide. Improving awareness of RSV among patients, policymakers, and health care providers is crucial to promote prevention through vaccination.
Pharmacists must stay up to date on current and new vaccination recommendations to help all patients make informed decisions about their immunizations.
About the Author
Kirsten Werner is a 2023 PharmD candidate at the University of Connecticut.