Systematic Literature Review of Respiratory Syncytial Virus Laboratory Testing Practices and Incidence in United States Infants and Children <5 Years of Age

Trends in RSV testing patterns among infants presenting with bronchiolitis: Results from four United States health systems, 2015-2023

BACKGROUND

Bronchiolitis due to respiratory syncytial virus (RSV) is the leading cause of hospitalization among American infants. The overall burden of RSV among infants has been historically under-estimated due to variable testing practices, particularly in the outpatient setting. Universal masking and social distancing implemented during the coronavirus disease 2019 (COVID-19) pandemic altered RSV seasonality, however potential consequences on RSV testing practices across different healthcare settings and sociodemographic groups have not been described. Variable testing practices could also affect accurate assessment of the effects of two recently approved RSV preventative agents targeting infants.

METHODS

Utilizing real-time clinical and viral surveillance, we examined RSV testing practices among infants with bronchiolitis within four United States healthcare systems across different healthcare settings and sociodemographic groups pre- and post-COVID-19.

RESULTS

RSV testing among infants with bronchiolitis increased since 2015 within each healthcare system across all healthcare settings and sociodemographic groups, with a more dramatic increase since the COVID-19 pandemic. Outpatient testing remained disproportionately low compared to hospital-based testing, although there were no major differences in testing frequency among sociodemographic groups in either setting.

CONCLUSIONS

Although RSV testing increased among infants with bronchiolitis, relatively low outpatient testing rates remain a key barrier to accurate RSV surveillance.

Healthcare Utilization Among Infants Covered by Medicaid and Newly Diagnosed With Respiratory Syncytial Virus

Background

Infants covered by Medicaid have higher respiratory syncytial virus (RSV) hospitalization rates than those with commercial insurance, but findings are limited to the inpatient setting. This birth cohort study describes healthcare encounters for RSV across all settings among infants covered by Medicaid and the Children's Health Insurance Program.

Methods

Medicaid claims for infants born and residing in Arizona (AZ), California (CA), Florida (FL), Michigan (MI), North Carolina (NC), New York (NY), and Texas (TX) were analyzed for first diagnosis of RSV in 2016-2018 using International Classification of Diseases, Tenth Revision codes. Encounters on the day of first diagnosis were examined by setting in 7 states and by setting and race in CA, FL, and NC.

Results

A total of 80 945 infants were diagnosed with RSV in 7 states in 2016-2018. The highest encounter rates for first RSV diagnosis were in the emergency department (ED) in 5 states (11.0-33.4 per 1000 in AZ, CA, FL, MI, and NY) and outpatient setting in 2 states (54.8 and 68.5 per 1000 in TX and NC). Significantly higher outpatient encounter rates were found in CA and NC for White infants compared to non-White infants. In NC, ED encounter rates were significantly higher for non-White infants than White infants, whereas in CA, the rates were comparable. In these 2 states, hospitalization rates were similar across groups. In FL, compared with White infants, non-White infants had significantly higher encounter rates in each setting on the day of first RSV diagnosis.

Conclusions

This is the first study to describe the burden of RSV by setting and race. Medicaid infants who are newly diagnosed with RSV have the highest burden in ED and outpatient settings.

Epidemiology of RSV Bronchiolitis Among Young Children in Central New York Before and After the Onset of the COVID-19 Pandemic

BACKGROUND

Respiratory syncytial virus (RSV) bronchiolitis is the leading cause of hospitalizations among infants in the United States. Unpredictability in RSV seasonality has occurred following the onset of the coronavirus disease 2019 (COVID-19) pandemic. Local surveillance networks can enhance the ability to appropriately time prophylaxis when exposure risk is highest.

METHODS

A retrospective, cohort study was conducted to describe the epidemiologic patterns of RSV disease among outpatient, emergency department and inpatient encounters in children <5 years in Central New York before and after the onset of the COVID-19 pandemic. Local data were collected from October 2015 to January 2023 and compared to state-level data. Linear regression models were used to identify clinical and sociodemographic differences before and after the pandemic.

RESULTS

Local variation in RSV seasonality was noted prior to the COVID-19 pandemic, however highly atypical circulation patterns appeared in the post-COVID-19 era. Since March 2020, patterns for local and state-defined RSV seasons have remained atypical (local season onset in 2021: week 27 and 2022: week 27; state season onset in 2021: week 31 and 2022: week 38). After adjusting for increases in testing, RSV bronchiolitis cases were not significantly different during pre- and post-pandemic eras. In comparison to the 2021 bronchiolitis season, the 2022 season had a higher proportion of RSV cases despite decreased testing.

CONCLUSIONS

Temporal patterns for RSV have shifted during the COVID-19 pandemic. Local surveillance networks may be advantageous in trending community-level RSV activity to optimize prophylaxis administration. Changes in RSV testing patterns occurred throughout the study period and should be accounted for when describing infant and childhood RSV disease.

Quality of life burden on United States infants and caregivers due to lower respiratory tract infection and adjusting for selective testing: Pilot prospective observational study

Background and Aims

Policymakers need data about the burden of respiratory syncytial virus (RSV) lower respiratory tract infections (LRTI) among infants. This study estimates quality of life (QoL) for otherwise healthy term US infants with RSV-LRTI and their caregivers, previously limited to premature and hospitalized infants, and corrects for selective testing.

Methods

The study enrolled infants <1 year with a clinically diagnosed LRTI encounter between January and May 2021. Using an established 0-100 scale, the 36 infants' and caregivers' QoL at enrollment and quality-adjusted life year losses per 1000 LRTI episodes (quality-adjusted life years [QALYs]/1000) were validated and analyzed. Regression analyses examined predictors of RSV-testing and RSV-positivity, creating modeled positives.

Results

Mean QoL at enrollment in outpatient (n = 11) LRTI-tested infants (66.4) was lower than that in not-tested LRTI infants (79.6, p = 0.096). For outpatient LRTI infants (n = 23), median QALYs/1000 losses were 9.8 and 0.25 for their caregivers. RSV-positive outpatient LRTI infants (n = 6) had significantly milder QALYs/1000 losses (7.0) than other LRTI-tested infants (n = 5)(21.8, p = 0.030). Visits earlier in the year were more likely to be RSV-positive than later visits (p = 0.023). Modeled RSV-positivity (51.9%) was lower than the observed rate (55.0%). Infants' and caregivers' QALYs/1000 loss were positively correlated (rho = 0.34, p = 0.046), indicating that infants perceived as sicker imposed greater burdens on caregivers.

Conclusions

The overall median QALYs/1000 losses for LRTI (9.0) and RSV-LRTI (5.6) in US infants are substantial, with additional losses for their caregivers (0.25 and 0.20, respectively). These losses extend equally to outpatient episodes. This study is the first reporting QALY losses for infants with LRTI born at term or presenting in nonhospitalized settings, and their caregivers.

Respiratory Syncytial Virus During the COVID-19 Pandemic Compared to Historic Levels: A Retrospective Cohort Study of a Health System

Background

Surveillance in 2020–2021 showed that seasonal respiratory illnesses were below levels seen during prior seasons, with the exception of interseasonal respiratory syncytial virus (RSV).

Methods

Electronic health record data of infants aged <1 year visiting the Duke University Health System from 4 October 2015 to 28 March 2020 (pre–COVID-19) and 29 March 2020 to 30 October 2021 (COVID-19) were assessed. International Classification of Diseases-Tenth Revision (ICD-10) codes for RSV (B97.4, J12.1, J20.5, J21.0) and bronchiolitis (RSV codes plus J21.8, J21.9) were used to detail encounters in the inpatient (IP), emergency department (ED), outpatient (OP), urgent care (UC), and telemedicine (TM) settings.

Results

Pre–COVID-19, 88% of RSV and 92% of bronchiolitis encounters were seen in ambulatory settings. During COVID-19, 94% and 93%, respectively, occurred in ambulatory settings. Pre–COVID-19, the highest RSV proportion was observed in December–January (up to 38% in ED), while the peaks during COVID-19 were seen in July–September (up to 41% in ED) across all settings. RSV laboratory testing among RSV encounters was low during pre–COVID-19 (IP, 51%; ED, 51%; OP, 41%; UC, 84%) and COVID-19 outside of UC (IP, 33%; ED, 47%; OP, 47%; UC, 87%). Full-term, otherwise healthy infants comprised most RSV encounters (pre–COVID-19, up to 57% in OP; COVID-19, up to 82% in TM).

Conclusions

With the interruption of historical RSV epidemiologic trends and the emergence of interseasonal disease during COVID-19, continued monitoring of RSV is warranted across all settings as the changing RSV epidemiology could affect the distribution of health care resources and public health policy.