Neonatal Fever in the COVID-19 Era: Odds of a Serious Bacterial Infection

Background:

Background: Pre-COVID literature suggests that viral infections account for about 90% of cases of fever in infants ≤56 days of age. Given the reduction in non-SARS-CoV-2 viral infections observed during the COVID-19 pandemic, we sought to determine if SBI accounted for a higher than usual proportion of fever cases in this age group during this period.

Methods:

Methods: We performed a multi-center, retrospective chart review of infants age ≤56 days presenting with fever to emergency departments (EDs) of six community hospitals affiliated with the same academic children’s hospital. We compared the incidence of SBIs, viral meningitis, and viral bronchiolitis during March 2020 - February 2021 (pandemic year) with the same calendar months in the two preceding years (pre-pandemic years).

Results:

Results: From March 2018 to February 2021, 543 febrile infants presented to the EDs, 95 during the pandemic year (Mar 2020-Feb 2021) compared to 231 and 217 in the pre-pandemic years (Mar 2018-Feb 2019 and Mar 2019-Feb 2020, respectively). The incidence of SBI was 28.4% (27/95) during the pandemic year compared to 11.6% (27/231) and 6.9% (15/217) in the pre-pandemic years (p < 0.001); bacteremia 13.7% (13/95) during the pandemic year compared to 2.2% (5/231) and 1.4% (3/217) in the pre-pandemic years; and UTI 19% (18/95) during the pandemic compared to 11.3% (26/231) and 6.5% (14/217) in the pre-pandemic years (TABLE 1). Five patients were diagnosed with bacterial meningitis over the three-year period, four of them during the pandemic year, a rate of 4.2% (4/95). Rate of positivity for viral CSF PCR during the pandemic year was 6.4% (3/47) compared to 20.8% (25/120) and 20.4% (23/113) in the pre-pandemic years (Mar 2018-Feb 2019 and Mar 2019-Feb 2020 respectively; p=0.070). 2.1% (2/95) febrile young infants were admitted with a co-morbid diagnosis of bronchiolitis during the pandemic year compared to 4.3% (10/231) and 6.0% (13/217) in the pre-pandemic years (Mar 2018-Feb 2019 and Mar 2019-Feb 2020 respectively; p=0.310).
The risk ratio for SBI (FIGURE 1) for pre-pandemic year 1 (referent; Mar 2018-Feb 2019) compared to the pandemic year (Mar 2020-Feb 2021) was 2.43 (95% CI 1.51-3.92; Bonferroni adjusted p=0.001); and the risk ratio for pre-pandemic year 2 (referent; Mar 2019-Feb 2020) compared to the pandemic year was 4.11 (95%CI 2.29-7.37; Bonferroni adjusted p<0.001).

Conclusion:

Conclusion: The COVID-19 pandemic led to an increase in the proportion of SBIs among febrile infants ≤56 days of age. This is likely a result of reduction in non-SARS-CoV-2 viral infections. Greater vigilance is thus warranted in the evaluation of febrile infants during the COVID-19 pandemic.