

1. In a study of children seen at a New York City hospital, the onset of RSV cases in 2020-2021 shifted from the typical fall season to the spring season.

2. There were also more PICU admissions, a younger patient population, and an increase in hospital length of stay.

Evidence level: 2 (good)

Study Rundown:

RSV is a common cause of severe respiratory infections in young children. Usually, RSV infections peak during the fall season and decrease during the spring and summer months. However, increased public health measures such as social distancing and masking due to the COVID-19 pandemic are thought to have shifted the trajectory of RSV infections. In this single-center retrospective cohort study, researchers compared the number of RSV infections per season from 2016 to 2021. The 2020-2021 season differed dramatically compared to prior years in that the first infection occurred in February 2021 and cases continued to rise through the end of the study period in May. During the 2020-2021 season, the average age of the patients was younger, length of hospitalization was longer, and more children required intensive care. Although widespread application may be limited by its single-center design, this study highlights the dramatic change in the current RSV season and the need for hospitals to prepare to avoid being overwhelmed.

In-depth [retrospective cohort]:

This is a retrospective cohort study analyzing RSV PCR data between January 2016 to May 8, 2021. Children aged 0-18 years old (n= 295) who presented to Maimonides Children’s Hospital in New York City and tested positive for RSV were included. 66.7% of subjects were admitted to the hospital; 81% of hospitalized children were admitted to the pediatric intensive care unit (PICU). There was a similar pattern of RSV infections from 2016 to 2019, which varied markedly compared to the 2020-2021 season as described above. When compared to past seasons, patients during the 2020-2021 season were younger (median age: 6 vs. 17 months) and had longer median hospital stays (4 vs. 3 days). Additionally, more patients were admitted to the PICU (81 vs. 45%) than before. This pattern mirrors that which was seen in Western Australia during the COVID-19 pandemic.
