Disruption in seasonality, patient characteristics and disparities of respiratory syncytial virus infection among young children in the US during and before the COVID-19 pandemic: 2010-2022

Abstract

Respiratory syncytial virus (RSV) infections and hospitalization have surged sharply among young children. Here we test how the seasonal patterns of RSV infections in 2022 compared with those from other COVID-19 pandemic and pre-pandemic years. For this purpose, we analyzed a nation-wide and real-time database of electronic health records of 56 million patients across 50 states in the US. The monthly incidence rate of first-time RSV infection in young children (<5 years of age) and very young children (<1 year of age) followed a seasonal pattern from 2010 to 2019 with increases during the autumn, peaking in winter, subsiding in spring and summer. This seasonal pattern was significantly disrupted during the COVID-19 pandemic. In 2020, the incidence rate of RSV infections was remarkably low throughout the year. In 2021, the RSV season expanded to 9 months starting in the early summer and peaking in October. In 2022, RSV infections started to rise in May and were significantly higher than in previous years reaching a historically highest incidence rate in November 2022. There were significant racial and ethnic disparities in the peak RSV infection rate during 2010-2021 and the disparities further exacerbated in 2022 with peak incidence rate in black and Hispanic children 2-3 times that in white children. Among RSV-infected children in 2022, 19.2% had prior documented COVID-19 infection, significantly higher than the 9.7% among uninfected children, suggesting that prior COVID-19 could be a risk factor for RSV infection or that there are common risk factors for both viral infections. Our study calls for continuous monitoring of RSV infection in young children alongside its clinical outcomes and for future work to assess potential COVID-19 related risk factors.

Epidemiological characteristics of respiratory syncytial virus infection in pediatric patients before, during the COVID‐19 pandemic and after easing of COVID‐19 restrictive measures in China

“…We also found that the RSV season expanded to 8 months (defined as RSV positive rate ≥2.5%) in 2021 and 7 months in 2022 in contrast to the previous years (3 months in 2019 and 4 months in 2020). This phenomenon was surprisingly similar to the results of a study conducted in the United States which included 56 million pediatric patients 32. A study from Australia reported a major reduction in RSV genetic diversity since the COVID-19 pandemic, and suggested that mitigation measures may disrupt seasonal pattern during COVID-19 pandemic as well as cause larger and more severe RSV outbreaks in post COVID-19 phase 10.…”

Respiratory Syncytial Virus Infections in Polish Pediatric Patients from an Expert Perspective

“…This led to variations in the circulation of common respiratory viruses, including RSV. After the initial decline of cases, when restrictions were lifted, a shift in seasonality and delayed outbreaks of RSV were observed in several countries [ 24 , 25 , 27 , 57 , 58 , 59 , 60 , 61 , 62 ]. This pattern was confirmed by Polish investigators, although data are limited.…”

Global Seasonal Activities of Respiratory Syncytial Virus Before the Coronavirus Disease 2019 Pandemic: A Systematic Review

“…During the COVID-19 pandemic, circulation of respiratory viruses including RSV changed considerably worldwide largely due to implementation of nonpharmaceutical interventions and changes in human behaviors in response to the pandemic [ 51 , 52 ]. RSV remained at a low level in many countries in 2020, when public health and social measures were widely adopted globally to contain the spread of severe acute respiratory syndrome coronavirus 2, but caused surges of infections with a large number of severe cases admitted into hospital in some countries when some interventions were relaxed from 2021 onward [ 53 , 54 ], including the US during 2021–2023 [ 55 ], some geographically separated locations in Australia in 2020–2021 [ 56 ], and the United Kingdom in 2021–2022 [ 57 ]. The interseasonal viral activities were perhaps related to the increased susceptibility in the population due to the lack of exposure to RSV during the previous years in response to COVID-19 [ 58 ].…”