Young children, especially those below 5 years of age, hospitalized with Covid-19 are more likely to develop severe respiratory illness if they also test positive for another respiratory virus compared to those who test negative for other viruses, suggests a study published in the journal Pediatrics.¹

Children hospitalized due to Covid-19 were enrolled in this study to examine the impact of respiratory virus codetections. Data for the study was obtained from the US Covid-19 Associated Hospitalization Surveillance. Network (COVID-NET) between March 2020 to February 2022 from across the United States. Out of the 4372 children included in the analysis, 2659 were tested for minimum one respiratory virus aside from Covid-19.  Of these, 1670 (62%) underwent complete additional viral testing. Viral codetection was defined in the study as a positive SARS-CoV-2 test during hospital stay or during the 14 days preceding the hospital admission plus and a positive PCR test for at least 1 other respiratory virus in the 14 days before, or during the first week of hospitalization.  

Among children who were tested for non-SARS-CoV-2 infections, 537 (21%) also tested positive for at least one other respiratory virus besides a positive test for SARS-CoV-2. Fifteen percent tested positive for rhinovirus or enterovirus, 10% for other viruses, 7% for RSV, while just 1% were positive for influenza. When codetections were analyzed age-wise, 11% of children under 2 years of age were positive for RSV (vs less than 1% among 12-17 years) and 28% in the age group 2-4 years were positive for rhinovirus or enterovirus (vs 5% in the age group 12-17 years vs 24% among children younger than 2 years).

Among hospitalized children under 5 years of age, presence of any virus codetection or codetection of rhinovirus/enterovirus doubled the probability of severe respiratory illness compared with children with negative viral testing. Similarly, hospitalized children younger than 2 years with RSV codetection were twice more likely to have severe illness (aOR 1.9) compared to children who did not have RSV infection. No such associations were observed for children older than 5 years.

This study highlights the clinical significance of codetections in children with Covid-19. Children with codetections tended to be younger (under-5) in age; they were also more likely to require oxygen supplementation or intensive care indicating severe illness. It further shows that though respiratory virus codetections were rare during the first years of the pandemic, RSV and rhinovirus or enterovirus codetections increased in frequency during the second wave when the delta was the predominant variant. However, influenza codetection was less common during the first couple of years of the pandemic. Hence, testing for other circulating respiratory viruses may help to prognosticate children, especially children younger than 5 years of age, hospitalized with Covid-like respiratory illness or Covid-19.

Reference

1. Nickolas T. Agathis, et al; CDC COVID-NET Surveillance Team. Codetections of other respiratory viruses among children hospitalized with COVID-19. Pediatrics Jan. 18, 2023; e2022059037. https://doi.org/10.1542/peds.2022-059037