Background: Recent studies highlight RSV as an important cause of cardiorespiratory disease in adults, particularly older adults. Existing burden estimates, largely from high-income countries with temperate climates, show RSV-associated hospitalization incidence increases with age and varies across time and regions. However, data from low- and middle-income or tropical and subtropical regions remain limited, leaving global adult RSV burden poorly characterized.
Methods: This population-based modeling study followed a Global Burden of Disease framework. Using weekly surveillance data from 129 countries (2015-2022), we generated a global time series of predicted RSV exposure with a spatiotemporal regression model (RegMod) incorporating covariates, such as season, hemisphere, temperature and humidity. We then produced country-level exposure-response curves (ERCs) for a diverse set of 19 countries spanning North America, Europe, Asia, Oceania, and Latin America using Bayesian non-parametric estimation, adjusting for long-term and seasonal trends, influenza and Covid-19 activity, and meteorology. A global ERC was derived through meta-regression, using a Bayesian, regularized, trimming model that tested the influence of covariates such as temperature, humidity, air pollution, population density, and urbanicity on curve shape. Metaregressed ERCs were combined with population exposures from RegMod to estimate the population attributable fractions (PAFs). Finally, RSV-attributable respiratory and cardiorespiratory hospitalizations were calculated for every country by multiplying PAFs by overall hospitalizations from a spatiotemporal Gaussian process regression tool, informed by data from 254 locations and covariates, including healthcare access and quality index, sociodemographic index, and physicians per capita.
Results: The average annual positive proportion of RSV showed a pronounced global pattern, with lowest values in parts of Sub-Saharan Africa (excluding the Sahel) and Latin America and highest levels in Oceania, the Sahel, and southern South America, ranging globally from 1% to 15% for all ages. We found a significant relationship between population-level RSV positive proportion and respiratory and cardiorespiratory hospital admissions across the aggregated 19 countries that had hospitalization data analyzed encompassing a wide range of climatic, sociodemographic, and health system contexts, for all adult age groups (18 years and older). Globally, during pre-pandemic years (2015-2019) RSV accounted for an estimated 11.1% (10.8–11.5) of cardiorespiratory and 13.1% (12.8–13.6) of respiratory hospitalizations among adults (Figure 1). This corresponds to roughly 6.4 million (6.2–6.7) and 5.6 million (5.5–5.8) admissions per year (Figure 2), respectively.
Interpretation: This study extends knowledge of RSV burden among adults beyond high-income countries, demonstrating that adults in low- and middle-income regions might benefit from preventive measures.