Yesterday in Morbidity and Mortality Weekly Report, investigators describe a deadly outbreak of meningococcal disease primarily in Virginia's Eastern Health Planning Region from 2022 to 2024. The outbreak is notable, as almost 80% of the cases occurred in Black residents, and 63.9% were in an age group (30 to 60 years) not generally considered at increased risk of invasive meningococcal disease (IMD).
From 2012 to 2022, the Eastern Health Planning Region reported an average of only one IMD case annually. In July and August 2022, four patients were identified as being infected with N. meningitidis serogroup Y.
"No common exposures, epidemiologic linkages, or specific risk factors were identified among the four cases," the authors wrote. From June 2022 and March 2024, officials recorded 36 confirmed and 1 probable case of IMD, with 25 in the Eastern Health Planning Region.
Case-fatality rate near 20%
All patients required hospitalization, and seven died from complications, resulting in a case-fatality rate for this outbreak of 19.4%.
In December 2022, the Virginia Department of Health recommended that local health departments in the Eastern Region offer one dose of MenACWY vaccine, in addition to antimicrobial post-exposure prophylaxis (prevention) to a subset of close case contacts. In August 2023 the recommendation was expanded statewide.
Lack of a well-defined population at risk during this outbreak posed a challenge to implementing vaccination as an outbreak control strategy.
"Lack of a well-defined population at risk during this outbreak posed a challenge to implementing vaccination as an outbreak control strategy," the report concluded. "In this outbreak, selective vaccination of close contacts (in addition to antimicrobial prophylaxis) was recommended in an effort to prevent additional cases among a population presumed to be at risk. Unfortunately, low vaccine acceptance precluded evaluation of the impact of this intervention on outbreak progression."