Respiratory syncytial virus infection among people experiencing homelessness

From Dr. Denise McCulloch, Vaccine and Infectious Disease Division, Fred Hutch and Division of Allergy and Infectious Diseases, UW, and colleagues

Crowded shelters or densely populated living spaces provide the perfect opportunity for transmission of respiratory viruses such as respiratory syncytial virus (RSV) - a common respiratory pathogen that can lead to severe infection in infants and older adults - putting an already vulnerable population, people experiencing homelessness, at greater risk of infection. Further exacerbating this risk, is the increase of older adults and the higher level of chronic conditions such as asthma and heart disease, conditions that are associated with more severe infection and hospitalization, among this population. “We know that many people who are experiencing homelessness have limited access to medical care, and often have medical conditions that put them at higher risk for severe infection with respiratory viruses. Furthermore, they may be at higher risk for acquiring infection due to crowded conditions in shelters. In healthy people, RSV is often a minor illness, with cold-like symptoms, but among vulnerable individuals, it can cause severe disease resulting in hospitalization, and even death,” explained Dr. Denise McCulloch, an Assistant Professor in the Fred Hutch Vaccine and Infectious Disease Division. Dr. McCulloch and colleagues conducted a 3-year study to assess RSV in homeless shelters across King County, Washington during RSV season. Their study, recently published in Influenza and Other Respiratory Viruses, described RSV cases, symptoms, and crossover with other seasonal respiratory viruses in people experiencing homelessness.

The researchers enrolled participants into this study by utilizing the infrastructure of existing larger studies, the Seattle Flu Study, and a randomized controlled trial for influenza testing in shelters. Participants ranged in age from 3 months to 97 years old. Asthma was reported as the most common co-morbidity, and 54% of adult encounters reported tobacco use, an additional risk factor for poorer health outcomes. Of the 35 RSV cases detected, 26% involved co-infection with another respiratory virus, most commonly influenza. Notably, the most frequently reported symptoms for both RSV and influenza were the same, cough and rhinorrhea (runny nose), emphasizing the difficulty in distinguishing between viruses without confirmatory testing. Moreover, many study participants reported how their RSV infection affected their ability to go about their daily activities, with several requiring doctor or emergency room visits.

Respiratory syncytial virus and influenza were not easily distinguishable among people experiencing homelessness in King County, Washington.
26% of RSV infections involved co-infection with another respiratory virus. Figure provided by Dr. McCulloch

Summarizing how Dr. McCulloch hopes the results from the present study will impact access to future RSV testing for vulnerable populations, she said “our findings underscore the difficulty of clinically distinguishing infections caused by RSV and flu, particularly during the peak winter respiratory virus season, when multiple viruses are circulating. I often see newspaper headlines saying things like, “How to know if your cold is the flu”, but in reality, there is so much overlap in the symptoms caused by these viruses, that testing is critical, especially for people most at risk for severe disease. So in the same way that testing for Covid has become more widely available over the past two years, I hope the same will soon be true for RSV.”

Going forward Dr. McCulloch and colleagues are focused on improving testing capabilities for vulnerable populations, those most at risk, and their communities. “We know that timely and accurate testing for respiratory viruses is important. As providers, and as a healthcare system, we are generally pretty good about testing our immunocompromised patients for respiratory viruses, but testing for their families, caregivers, and medical teams is much more limited,” said Dr. McCulloch. “In the future I’m interested in exploring how additional testing for the close contacts of immunocompromised patients could be a tool to help protect them from infection and to identify and interrupt outbreaks early in their course,” she concluded. 

This work was funded by support from the Centers for Disease Control and Prevention, Gates Ventures, and the National Institute of Allergy and Infectious Diseases of the National Institutes of Health.

Fred Hutch/University of Washington/Seattle Children's Cancer Consortium members Eric Chow, Michael Boeckh, Janet Englund, Jay Shendure, and Lea Starita contributed to this work.

McCulloch DJ, Rogers JH, Wang Y, Chow EJ, Link AC, Wolf CR, Uyeki TM, Rolfes MA, Mosites E, Sereewit J, Duchin JS, Sugg NK, Greninger AL, Boeckh MJ, Englund JA, Shendure J, Hughes JP, Starita LM, Roychoudhury P, Chu HY. Respiratory syncytial virus and other respiratory virus infections in residents of homeless shelters - King County, Washington, 2019-2021. Influenza Other Respir Viruses. 2023 Jun 19;17(6):e13166. doi: 10.1111/irv.13166. PMID: 37346095; PMCID: PMC10279995