COVID-19 Had Worst Disease Outcomes Among Respiratory Viruses
In their exploration of 2 separate respiratory virus seasons, researchers examined the severity of illness for SARS-CoV-2, influenza, and respiratory syncytial virus.
During the 2022-23 respiratory virus season, patients infected with SARS-CoV-2 experienced significantly worse disease outcomes when compared with influenza and respiratory syncytial virus (RSV). While these differences were less prominent in the following season, RSV remained significantly mild and COVID-19 had increased long-term mortality outcomes throughout both seasons, according to data published in JAMA Internal Medicine.1
“Respiratory viral illnesses caused by SARS-CoV-2, influenza, and RSV are associated with substantial morbidity and mortality in older adults and persons with chronic medical conditions,” wrote authors of the study. “In the US, influenza and COVID-19 vaccinations are recommended for all adults, and RSV vaccination is recommended for older adults. However, vaccine uptake remains low.”
The annual respiratory virus season from around August to March exhibits a significant uptick in COVID-19, influenza, and RSV cases. | image credit: FreyStudios / stock.adobe.com
As the researchers attempted to highlight in their study, the annual respiratory virus season from around August to March exhibits a significant uptick in COVID-19, influenza, and RSV cases. Along with a US population hesitant or unconcerned with immunization and keeping themselves protected against these diseases, health care providers typically use respiratory virus season to educate patients on the importance of vaccination in the winter months.
READ MORE: Simultaneous COVID-19, Influenza Vaccines Comparable with Sequential Immunization
“Conventionally, it was thought that cold and flu season occurred in cooler months because people are stuck indoors more where airborne viruses could spread more easily,” said Benjamin Bleier, senior author of a study exploring the link between cold temperatures and upper respiratory infections.2 “Our study, however, points to a biological root cause for the seasonal variation in upper respiratory viral infections we see each year, most recently demonstrated throughout the COVID-19 pandemic.”
With COVID-19 joining the flu and RSV in the respiratory virus season collective, researchers have since put a greater focus on how these viruses impact patients during the cold-weather months in many parts of the US. In the study of 2022-23 and 2023-24 respiratory virus seasons, researchers examined disease severity and mortality outcomes among US veterans.1
“This retrospective cohort study analyzed national US Veterans Health Administration electronic health record data of nonhospitalized veterans who underwent same-day testing for SARS-CoV-2, influenza, and RSV, and were diagnosed with a single infection between August 1, 2022, and March 31, 2023, or between August 1, 2023, and March 31, 2024,” wrote authors of the study.
The main outcome of the study was any hospitalization, ICU admission, or report of death within 30 days of a patient receiving a diagnosis of influenza A or B, RSV, or SARS-CoV-2. Researchers also explored if patients reported death in between 90 and 180 days following the index date.
Separating participants into similarly numbered groups, a total of 68,581 veterans were included in the 2022-23 season and 72,939 for the 2023-24 season. Among those included within the 2022-23 season, 6239 had RSV (9.1%), 16,947 had influenza (24.7%), and 45,395 had COVID-19 (66.2%). For the 2023-24 respiratory virus season group, 9748 had RSV (13.4%), 19,242 had influenza (26.4%), and 43,949 had COVID-19 (60.3%).1
For study participants included in the 2022-23 season, hospitalizations occurred in 17.5% of patients with a COVID-19 diagnosis, 15.9% of influenza diagnoses, and 14.4% of RSV diagnoses. In the 2023-24 season, however, hospitalizations occurred in 16.3% of veterans diagnosed with influenza, 16.2% of those diagnosed with COVID-19, and 14.3% of those diagnosed with RSV.
Despite patient risk patterns between both seasons showing similarities, 2022-23 represented significantly higher ICU admission rates for COVID-19, compared with influenza and RSV. Again, for patients with COVID-19, they had the highest occurrence of death compared with RSV and influenza in both respiratory virus seasons.
“Among more than 141,000 nonhospitalized US veterans included in this cohort study, who were diagnosed with COVID-19, influenza, or RSV, and concurrently tested for all 3 viruses during the 2022 to 2023 or 2023 to 2024 respiratory illness seasons, COVID-19 was by far the most common diagnosis, and 30-day risk of hospitalization was lowest among persons with RSV,” continued the authors.1
Furthermore, hospitalization risks were similar for patients who were diagnosed with either COVID-19 or influenza, but ICU admissions were more likely in those with COVID-19 compared with influenza. While only modestly higher, researchers also noted an increase in mortality risk among veterans with COVID-19.
“In this cohort study, which provided contemporary data comparing SARS-CoV-2, influenza, and RSV infection diagnosed in nonhospitalized patients, SARS-CoV-2 was far more common than influenza or RSV and resulted in more severe disease outcomes, including short-term hospitalization and mortality through 6 months,” concluded authors of the study.1 “This was most apparent among older adults and attenuated by updated COVID-19 vaccination. Vaccination remains an important strategy for minimizing the impact of RVIs and particularly Omicron variants.”
READ MORE: Immunization Resource Center
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