Increase in Invasive Serogroup Y Meningococcal Disease in the U.S.

Actions requested

• Be aware of an increase in invasive meningococcal disease mainly attributable to Neisseria meningitidis (N. meningitidis) serogroup Y.
• Be alert to the possibility of meningococcal disease among all persons and start immediate antibiotic treatment for persons with suspected meningococcal disease.. 
• Current increases are disproportionately affecting people ages 30–60 years, Black or African American people, and people with HIV.
• Consider meningococcal disease in persons with compatible illness. Some patients may present with bloodstream infection or septic arthritis without symptoms typical of meningitis (e.g., headache, stiff neck):
• Meningococcal meningitis: Symptoms include fever, headache, stiff neck, nausea, vomiting, photophobia, and altered mental status.
• Meningococcemia: Symptoms include fever, fatigue, vomiting, cold extremities, chills, myalgia, arthralgia, chest pain, abdominal pain, tachypnea, diarrhea, and purpuric rash (late stage). 
• Ensure patients are up to date on recommended meningococcal vaccines especially for younger children and adults at increased risk including persons with HIV. 
• Immediately report suspected or confirmed cases of invasive meningococcal disease to Public Health at (206) 296-4774.

Background

Meningococcal disease, caused by the bacterium N. meningitidis, is a rare but severe disease with a case-fatality rate of 10-15% even with appropriate antibiotic treatment. While initial symptoms of meningococcal disease can be non-specific, illness can worsen rapidly, and become life threatening within hours. Immediate antibiotic treatment for suspected meningococcal disease is critical. Survivors may experience long-term effects such as deafness or extremity amputation.

Increases in invasive meningococcal disease have not been detected in King County (in 2023, one case of meningococcal disease, serogroup Y was reported, and no cases so far in 2024).  However, national increases in case reports were reported to CDC in 2023 (n=422) and year to date 2024 (n=143). A specific meningococcal strain, sequence type (ST) 1466, is responsible for most serogroup Y cases with available sequence data.

Most cases of invasive meningococcal disease caused by ST 1466 in 2023 had a clinical presentation other than meningitis: 64% presented with bacteremia and 4% with septic arthritis. Of 94 patients with known outcomes, 17 (18%) died; this case fatality rate is higher than the historical case fatality rate of 11% reported for serogroup Y cases in 2017–2021. The serogroup Y ST-1466 strain has contributed to previously reported increases in meningococcal disease in people with HIV. Serogroup Y ST-1466 isolates tested to date have been susceptible to all first line antibiotics recommended for treatment and post exposure prophylaxis. Based on updated surveillance data, 24 ST-1466 cases have now been reported in people with HIV in 2022–2023; only four were previously vaccinated with MenACWY and none were up to date on recommended doses. To date, no other ST-1466 cases have been identified in people who previously received MenACWY vaccine.