Among infants younger than 1 year of age, bacterial meningitis is associated with worse long-term mortality, even after recovery from the initial infection. Heightened mortality risk stretched out to 10 years, and was highest in the wake of infection from Streptococcus agalactiae, according to a retrospective analysis of children in the Netherlands.
“The adjusted hazard rates were high for the whole group of bacterial meningitis, especially within the first year after onset. (Staphylococcus agalactiae) meningitis has the highest mortality risk within one year of disease onset,” Linde Snoek said during her presentation of the study (abstract 913) at the annual meeting of the European Society for Paediatric Infectious Diseases, held virtually this year. Ms. Snoek is a PhD student at Amsterdam University Medical Center.
Over longer time periods, the mortality associations were different. “The adjusted hazard rates were highest for pneumococcal meningitis compared to the other pathogens. And this was the case for 1 year, 5 years, and 10 years after disease onset,” said Ms. Snoek.
The study appears to be the first to look at extended mortality following bacterial meningitis in this age group, according to Marie Rohr, MD, who comoderated the session where the research was presented.
“In a quick review of the literature I did not find any [equivalent] study concerning short- and long-term mortality after bacterial meningitis in under 1 year of age,” said Dr. Rohr, a fellow in pediatric infectious diseases at University Hospitals of Geneva. But the message to physicians is clear. “Children with history of bacterial meningitis have a higher long-term mortality than children without a history of bacterial meningitis,” said Dr. Rohr.
The study did have a key limitation: For matched controls, it relied on anonymous data from the Municipal Personal Records Database in Statistics Netherlands. “Important information like cause of death is lacking,” said Dr. Rohr.
Bacterial meningitis is associated with significant mortality and morbidity. Pathogens behind the infections vary with age group and geographic location, as well as immunization status.
To examine long-term mortality after bacterial meningitis, the researchers collected 1,646 records from an exposed cohort, with a date range of 1995 to 2018, from the Netherlands Reference Laboratory for Bacterial Meningitis. Included patients had a positive culture diagnosis of bacterial meningitis during the first year of life. Each exposed subject was compared to 10 controls matched by birth month, birth year, and sex, who had no exposure to bacterial meningitis.
Staphylococcus pneumoniae accounted for the most cases, at 32.0% (median age of onset, 180 days), followed by Neisseria meningitidis at 29.0% (median age of onset, 203 days). Other pathogens included S. agalactiae (19.7%, 10 days), Escherichia coli (8.8%, 13 days), and Haemophilus influenzae (5.4%, 231 days).
The mortality risk within 1 year of disease onset was higher for all pathogens (6.2% vs. 0.2% unexposed). The highest mortality risk was seen for S. agalactiae (8.7%), followed by E. coli (6.4%), N. meningitidis (4.9%), and H. influenzae (3.4%).
Hazard ratios (HR) for mortality were also higher, particularly in the first year after disease onset. For all pathogens, mortality rates were higher within 1 year (HR, 39.2), 5 years (HR, 28.7), and 10 years (HR, 24.1). The consistently highest mortality rates were associated with S. pneumoniae over 1-year, 5-year, and 10-year follow-up (HR, 42.8; HR, 45.6; HR, 40.6, respectively). Within 1 year, the highest mortality rate was associated with N. meningitidis (HR, 58.4).
Ms. Snoek and Dr. Rohr have no relevant financial disclosures.