Severe COVID-19 Illness Linked to Prior Respiratory Syncytial Viral Infection, Study Finds

A significant link has been identified between prior respiratory syncytial virus (RSV) infections and severe COVID-19 illness, suggesting that individuals with a history of RSV may be at greater risk for experiencing severe complications if they contract COVID-19.¹

The main outcome measure was severity of COVID-19 illness assessed based on hospitalizations, intensive care unit (ICU) admissions, and mortality rates. | Image credit: MargJohnsonVA - stock.adobe.com

This retrospective cohort study was published in the European Journal of Allergy and Clinical Immunology.

“Although the possible impact of ethnicity exists in our study, this study is, to our knowledge, the first to assess how previous RSV infections affect the clinical progression of future COVID-19 in the general population,” the researchers of the study wrote.

Symptoms of influenza (flu), RSV, and COVID-19 are similar and may include fever, cough, and shortness of breath. Because the symptoms coincide, it can be difficult to distinguish between illnesses caused by respiratory viruses, according to the National Foundation for Infectious Diseases.²

The study utilized the national health database to gather patient records, including patient demographics, medical histories, RSV infection records, and COVID-19 diagnosis and severity.¹ Patients included in the study had documented RSV infections within the 3 years (2017 to 2019) prior to the COVID-19 pandemic and were diagnosed with COVID-19 during the study period. Additionally, a control group of patients with no history of RSV infection was included for comparison.

The main outcome measure was severity of COVID-19 illness assessed based on hospitalizations, intensive care unit (ICU) admissions, and mortality rates. Furthermore, these findings were validated using sensitivity analyses and cross-referencing with other datasets.

Of a total of 8,644,520 individuals in the National Health Insurance Service cohort database, 18,535 individuals had a record of RSV infection in the previous 3 years. These patients showed a significantly higher incidence of COVID-19 susceptibility than those in the non-infection group (1000 person years [PY], 56.1; adjusted HR, 1.11; 95% CI, 1.03-1.20). This trend was more prominent in patients with underlying conditions such as angina (adjusted HR, 1.50; 95% CI, 1.20-1.89).

Additionally, 743 of the 18,535 patients with prior RSV infection became infected with COVID-19, and these patients showed a significantly higher risk of hospitalization than those with no history of RSV infection (1000 PY, 1459.4; adjusted HR, 1.23; 95% CI, 1.02-1.48). While this trend was unaffected by demographic factors such as age, sex, economic status, or underlying diseases, individuals who had RSV infections within a year of COVID-19 infection exhibited higher HR significance than the controls (adjusted HR, 1.50; 95% CI, 1.09-2.09).

Furthermore, patients in the COVID-19 group with a history of RSV infection (1000 PY, 178.2) had a significantly higher risk of COVID-19 severity than those with no RSV infection history (1000 PY, 70.5; adjusted HR, 3.13; 95% CI, 1.58-6.19). This association was more pronounced in patients aged 65 years and older (adjusted HR, 5.35; 95% CI, 2.33-12.27), with diabetes (adjusted HR, 2.92; 95% CI, 1.26-6.77), and congestive heart failure (adjusted HR, 2.91; 95% CI, 1.17-2.23). Patients with RSV infections in the previous year also had a greater HR than controls (adjusted HR, 5.16; 95% CI, 2.21-12.09).

However, the researchers acknowledged some limitations to the study, including its retrospective design, potential for misclassification or underreporting of RSV infections and COVID-19 severity, lifestyle or environmental exposures, and that it might not be generalizable to populations outside the specific cohort analyzed, particularly if the cohort has unique demographic or health characteristics.

Despite these limitations, the researchers believe the study underscores the importance of monitoring and managing respiratory health to mitigate potential risks associated with COVID-19.

“Our data revealed that prior RSV infection increased susceptibility and hospitalization of COVID-19 patients,” the researchers wrote. “Notably, individuals who had an RSV infection within 3 years of COVID-19 development were at an increased risk of severe illness from SARS-CoV-2 infection.”

References

1. Lee HJ, Kim MJ, Kim JS, et al. Prior respiratory syncytial viral infection contributes to severe COVID‐19 illness: A nationwide cohort study. Allergy. Published online April 5, 2024. doi:10.1111/all.16118

2. Dalton M. How to tell the difference between flu, RSV, COVID-19, and the common cold. NFID. July 3, 2023. Accessed August 6, 2024. https://www.nfid.org/resource/how-to-tell-the-difference-between-flu-rsv-covid-19-and-the-common-cold/