CDC: Children's Brain Infections Rose Last Winter, but Remained Rare

Pediatric intracranial infections spiked recently and were associated with significant morbidity but remained rare, according to CDC researchers monitoring cases across the country.

Hospitalization data through March 2023 from 37 hospitals in 19 states and the District of Columbia showed a "higher-than-expected number" of pediatric intracranial infections, particularly those caused by Streptococcus bacteria, beginning in August 2021, "with a large peak" in the winter of 2022-2023, Emma Accorsi, PhD, of the CDC, and colleagues reported in the Morbidity and Mortality Weekly Report (MMWR).

Less than a year ago, the CDC researchers reported they had failed to find evidence of any unusual uptick in brain-related complications of bacterial infection among children, calling the peak in March 2022 "within normal historical limits."

In their new report, however, monthly case counts exceeded the median from August 2021 to March 2023, but did not exceed the baseline maximum until a large peak of 102 cases in December 2022. In 2023, from January to March, case counts began to decline but remained above the baseline maximum.

"Despite these observed increases, pediatric intracranial infections remain rare," Accorsi and colleagues concluded. "These infections are often preceded by viral respiratory infection and sinusitis, and recent trends might be driven by concurrent, heightened pediatric respiratory pathogen transmission."

Prepandemic baseline numbers of pediatric intracranial infection cases were a median of 34 and a maximum of 61 cases per month, based on hospitalization data from 2016 to 2019. After the onset of COVID in March 2020, monthly intracranial infection case counts remained below the baseline median from May 2020 to May 2021.

Though there was some variability between U.S. Census Bureau regions, overall patterns were generally similar across the country, Accorsi and colleagues reported.

Demographic characteristics of patients (age, race, ethnicity, and sex), measures of severity (length of hospitalization, intensive care unit admission and in-hospital mortality), and percentage of patients with a complex chronic condition were approximately stable over the study period and similar to values previously reported, they noted.

The group noted that all children and adolescents ages 18 and younger should be up-to-date on recommended vaccinations, including those for influenza and COVID, and that the CDC will continue to track trends related to pediatric intracranial infections.

Close Up on Clark County, Nevada

Last year, in Clark County, Nevada alone, there were 18 cases of pediatric patients hospitalized with intracranial abscesses, for a median of five cases per quarter -- up from the usual one case per quarter from 2015 to 2021, reported Jessica Penney, MD, of the CDC, and colleagues.

During the period preceding the COVID-19 pandemic (2015-2019), the quarterly median had been 0.5 cases in Clark County and during the first 2 years of the pandemic (2020-2021), the quarterly median reached 1.5 cases, the authors noted in a separate MMWR study.

A review of medical charts for the 18 cases reported found that sinusitis was diagnosed in 14 patients and that mastoiditis was diagnosed in four, Penney and colleagues reported. No patients received a positive test result for SARS-CoV-2 on admission, and there were no associated deaths reported.

The median patient age was 12 years and all but four cases occurred in boys. Patients were hospitalized for a median of 15 days, and 15 patients required craniotomy for abscess drainage.

From telephone interviews with 14 caregivers, nine reported their child having cold symptoms, including rhinorrhea, prior to hospitalization. Seven children experienced other symptoms, including headache (n=3), headache with fever (n=3), and mild head injuries (n=2).

Furthermore, 11 caregivers said they sought care for their child before hospitalization, most often at an emergency department (n=7), and the median interval from symptom onset to hospitalization was 7 days.

Nine caregivers reported that their child had been swimming during the 4 weeks prior to hospitalization, but not at the same pool locations. Five caregivers reported ending masking practices after the COVID mask mandate was lifted, including three who reported cold symptoms in their child before hospitalization.

"Although this investigation did not identify unexpected risk factors for intracranial abscesses, the substantial increase in cases after the mask mandate in Nevada was lifted might be partially attributable to changes in respiratory pathogen transmission," Penney and colleagues wrote.

The CDC group noted that the Southern Nevada Health District has released a health advisory notice about the the investigation's findings to local pediatric healthcare providers. Surveillance of pediatric intracranial infections will be continued through 2023.

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