Chest Infections & Disaster Response Network
Chest Infections Section
November 12 marks World Pneumonia Day, and while it has long been recognized that viruses play a significant role in causing pneumonia, awareness has surged due to the COVID-19 pandemic. Furthermore, with the advent of rapid molecular diagnostics, the contribution of respiratory viral pathogens in pneumonia has become clearer (Seema J, et al. N Engl J Med. 2015 Jul 30;373[5]:415-27). Despite COVID-19 remaining a substantial threat, infection rates with other respiratory viruses are on the rise and will continue to increase during colder months. Here, we will provide an update on influenza and RSV:
Currently, influenza activity in the United States is low (National Center for Immunization and Respiratory Diseases. FluView. 2023 Oct 4. https://www.cdc.gov/flu/weekly/index.htm). Vaccination coverage for US adults during the previous influenza season stood at 47% (Centers for Disease Control and Prevention. FluVaxView Vaccination Dashboard. 2023 Oct 4. https://www.cdc.gov/flu/fluvaxview/dashboard/vaccination-dashboard.html). Hospitalizations were estimated to range between 300,000 and 650,000, a significant increase from the 2021-2022 season, which saw about 100,000 hospitalizations (Centers for Disease Control and Prevention. Preliminary In-Season Estimates of Influenza Burden. 2023 Oct 4. https://www.cdc.gov/flu/about/burden/preliminary-in-season-estimates.htm). Data from the Southern Hemisphere’s recent influenza season indicates a 52% vaccine efficacy in preventing influenza-associated hospitalizations (Fowlkes AL, et al. MMWR Morb Mortal Wkly Rep. 2023 Sep 15;72[37]:1010-5). Influenza hospitalization rates are likely returning to higher pre-COVID-19 levels.
Respiratory Syncytial Virus (RSV) is a seasonal pathogen causing substantial morbidity and mortality. This year, two new vaccines have become available to prevent RSV-associated lower respiratory tract diseases, boasting a vaccine effectiveness of over 80% for the first and over 70% for the second season post-administration (Melgar M, et al. MMWR Morb Mortal Wkly Rep. 2023 Jul 21;72[29]:793-801). The CDC’s Advisory Committee on Immunization Practices recommends a single dose for adults over 60, and one vaccine is FDA-approved for pregnant individuals (32-36 weeks gestation) to provide passive infant immunity.
In summary, both the current influenza vaccine and the new RSV vaccines demonstrate effectiveness and are strongly recommended, alongside an updated COVID-19 vaccine.
John Huston, MD
Jamie Felzer, MD, MPH – Section Fellow-in-Training
Charles Dela Cruz, MD – Section Member-at-Large
Sebastian Kurz, MD, FCCP – Network Member-at-Large