Exploring the impact of population ageing on the spread of emerging respiratory infections and the associated burden of mortality

• Published in: BMC infectious diseases Vol. 23; no. 1; pp. 1 - 767
• Main Authors: Magelmose, Signe, Neels, Karel, Beutels, Philippe, Hens, Niel
• Format: Journal Article
• Language: English
• Published: London BioMed Central Ltd 07.11.2023; BioMed Central; BMC
• Subjects: Adults; Age; Age composition; Aging; Analysis; Belgium; COVID-19; Demographic change; Development and progression; Disease burden; Disease control; Disease transmission; Diseases; Emerging infectious diseases; Epidemics; Epidemiology; Fatalities; Fertility; Households; Infectious disease modelling; Infectious diseases; Influenza; Influenza A; Life expectancy; Life span; Long-term care; Long-term care of the sick; Lung diseases; Morbidity; Mortality; Older people; Outbreaks; Population ageing; Public health; Respiratory tract infection; Severe acute respiratory syndrome coronavirus 2; Single parents; Viral diseases; Viruses; Belgium
• ISSN: 1471-2334; 1471-2334
• DOI: 10.1186/s12879-023-08657-3

Increasing life expectancy and persistently low fertility levels have led to old population age structures in most high-income countries, and population ageing is expected to continue or even accelerate in the coming decades. While older adults on average have few interactions that potentially could lead to disease transmission, their morbidity and mortality due to infectious diseases, respiratory infections in particular, remain substantial. We aim to explore how population ageing affects the future transmission dynamics and mortality burden of emerging respiratory infections. Using longitudinal individual-level data from population registers, we model the Belgian population with evolving age and household structures, and explicitly consider long-term care facilities (LTCFs). Three scenarios are presented for the future proportion of older adults living in LTCFs. For each demographic scenario, we simulate outbreaks of SARS-CoV-2 and a novel influenza A virus in 2020, 2030, 2040 and 2050 and distinguish between household and community transmission. We estimate attack rates by age and household size/type, as well as disease-related deaths and the associated quality-adjusted life-years (QALYs) lost. As the population is ageing, small households and LTCFs become more prevalent. Additionally, families with children become smaller (i.e. low fertility, single-parent families). The overall attack rate slightly decreases as the population is ageing, but to a larger degree for influenza than for SARS-CoV-2 due to differential age-specific attack rates. Nevertheless, the number of deaths and QALY losses per 1,000 people is increasing for both infections and at a speed influenced by the share living in LTCFs.