The ageing of nasal tissues may explain why older people are more affected by COVID-19: research

Data from the World Health Organization (WHO) indicates that more than 80% of COVID-19-related deaths between 2020 and 2021 occurred in people aged 60 and above. Subsequent studies consistently highlighted the increased vulnerability of those over 65 to severe COVID-19 symptoms, and now researchers may have uncovered the reason behind this trend.

To comprehend how the coronavirus attacks our bodies, a study investigated the role of our noses, which are the initial point of contact with the virus. Researchers aimed to understand how nasal cells react to the SARS-CoV-2 virus, hoping to uncover insights for tailored treatment approaches for different age demographics.

The study focused on the early impact of SARS-CoV-2 infection on human nasal epithelial cells (NECs). Epithelial cells, abundant throughout our bodies, play crucial roles in bodily functions and protection. Researchers cultured NECs to replicate the nasal cavity's cellular environment and infected them with SARS-CoV-2.

Analysing cells from participants across various age brackets, including children (0-11 years), adults (30-50 years), and the elderly (over 70 years), the study identified age-specific responses to the virus. Children's NECs quickly increased interferon production upon SARS-CoV-2 exposure, effectively limiting viral replication.

In contrast, NECs from older individuals exhibited increased viral replication, accompanied by heightened cell shedding and damage. This disparity may explain why older people face a higher risk of severe COVID-19, despite widespread vaccination efforts.

Lead author Claire Smith explains, "Our research highlights age-related changes in nasal cells and their impact on our ability to combat SARS-CoV-2 infection. This insight is crucial for developing targeted antiviral treatments, especially for older adults who are at greater risk of severe COVID-19."

Understanding age-specific differences in nasal cell response to SARS-CoV-2 could lead to targeted antiviral therapies that boost interferon production in older adults, potentially reducing the severity of COVID-19 and lowering mortality rates in this demographic.

Furthermore, the study underscores the importance of considering age as a significant factor in researching and treating infectious diseases. Beyond COVID-19, future studies should explore how ageing affects the body's response to other viral infections, informing preventive measures and therapeutic interventions across different age groups.

The research findings have been published in Nature Microbiology and can be accessed here.