Incidence of Respiratory Syncytial Virus Infection in Older Adults Before and During the COVID-19 Pandemic

IMPORTANCE: Little is known about the burden and outcomes of respiratory syncytial virus (RSV)–positive acute respiratory infection (ARI) in community-dwelling older adults. OBJECTIVE: To assess the incidence of RSV-positive ARI before and during the COVID-19 pandemic, and to assess outcomes for RSV-positive ARI in older adults. DESIGN, SETTING, AND PARTICIPANTS: This was a community-based cohort study of adults residing in southeast Minnesota that followed up with 2325 adults aged 50 years or older for 2 RSV seasons (2019-2021) to assess the incidence of RSV-positive ARI. The study assessed outcomes at 2 to 4 weeks, 6 to 7 months, and 12 to 13 months after RSV-positive ARI. EXPOSURE: RSV-positive and -negative ARI. MAIN OUTCOMES AND MEASURES: RSV status was the main study outcome. Incidence and attack rates of RSV-positive ARI were calculated during each RSV season, including before (October 2019 to April 2020) and during (October 2020 to April 2021) COVID-19 pandemic, and further calculated during non-RSV season (May to September 2021) for assessing impact of COVID-19. The self-reported quality of life (QOL) by Short-Form Health Survey-36 (SF-36) and physical functional measures (eg, 6-minute walk and spirometry) at each time point was assessed. RESULTS: In this study of 2325 participants, the median (range) age of study participants was 67 (50-98) years, 1380 (59%) were female, and 2240 (96%) were non-Hispanic White individuals. The prepandemic incidence rate of RSV-positive ARI was 48.6 (95% CI, 36.9-62.9) per 1000 person-years with a 2.50% (95% CI, 1.90%-3.21%) attack rate. No RSV-positive ARI case was identified during the COVID-19 pandemic RSV season. Incidence of 10.2 (95% CI, 4.1-21.1) per 1000 person-years and attack rate of 0.42%; (95% CI, 0.17%-0.86%) were observed during the summer of 2021. Based on prepandemic RSV season results, participants with RSV-positive ARI (vs matched RSV-negative ARI) reported significantly lower QOL adjusted mean difference (limitations due to physical health, −16.7 [95% CI, −31.8 to −1.8]; fatigue, −8.4 [95% CI, −14.3 to −2.4]; and difficulty in social functioning, −11.9 [95% CI, −19.8 to −4.0] within 2 to 4 weeks after RSV-positive ARI [ie, short-term outcome]). Compared with participants with RSV-negative ARI, those with RSV-positive ARI also had lower QOL (fatigue: −4.0 [95% CI, −8.5 to −1.3]; difficulty in social functioning, −5.8 [95% CI, −10.3 to −1.3]; and limitation due to emotional problem, −7.0 [95% CI, −12.7 to −1.3] at 6 to 7 months after RSV-positive ARI [intermediate-term outcome]; fatigue, −4.4 [95% CI, −7.3 to −1.5]; difficulty in social functioning, −5.2 [95% CI, −8.7 to −1.7] and limitation due to emotional problem, −5.7 [95% CI, −10.7 to −0.6] at 12-13 months after RSV-positive ARI [ie, long-term outcomes]) independent of age, sex, race and/or ethnicity, socioeconomic status, and high-risk comorbidities. CONCLUSIONS AND RELEVANCE: In this cohort study, the burden of RSV-positive ARI in older adults during the pre-COVID-19 period was substantial. After a reduction of RSV-positive ARI incidence from October 2020 to April 2021, RSV-positive ARI re-emerged during the summer of 2021. RSV-positive ARI was associated with significant long-term lower QOL beyond the short-term lower QOL in older adults.