Q&A: What to know about the increase in invasive meningococcal disease
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Key takeaways:
- The CDC issued a health alert for invasive meningococcal disease caused by Neisseria meningitidis serogroup Y.
- Most cases have a clinical presentation other than meningitis.
The CDC alerted clinicians in the United States about a rise in invasive meningococcal disease caused by Neisseria meningitidis serogroup Y bacteria that could present with symptoms not typical of meningitis.
According to the CDC, 422 cases were reported in the U.S. in 2023 — the highest total since 2014. As of March 25, there have been 143 reported cases this year, an increase of 62 compared with the same date in 2023.
The fatality rate (18%) has been higher than normal for serogroup Y cases, and infections have disproportionately affected three populations, the CDC said: people aged 30 to 60 years (65% of cases), Black or African American people (63%) and people with HIV (15%), who have a higher risk for invasive meningococcal disease.
According to the CDC, most of the cases were caused by one strain, ST-1466. Patients with this strain have mostly had a clinical presentation other than meningitis: 64% presented with bacteremia and at least 4% presented with septic arthritis.
The CDC recommended that providers have a heightened suspicion for cases of meningococcal disease, be aware that cases may present atypically, and ensure that eligible patients, including those with HIV, are up to date on meningococcal vaccines.
“The mortality rate that we're now experiencing —18% — is really a jump,” Healio | Infectious Disease News Editorial Board Member William Schaffner, MD, professor of preventive medicine and infectious diseases at Vanderbilt University Medical Center, said in an interview. “I really suspect — although we haven't seen those data from the CDC — that it's taken a little longer to diagnose these people, so the infection has had a chance to become more severe and therefore associated with an increased risk of fatality.”
We checked in with Schaffner to get his reaction to the CDC alert and to ask what clinicians should be looking for.
Healio: What was your reaction to the CDC’s health alert?
Schaffner: Well, frankly, I was surprised. I was surprised because meningococcal disease has been on a rather steady decline for the last 10 to 12 years. This was not completely understood. It’s probably part of the usual but inexplicable changes in the meningococcal disease epidemiology that occur from time to time. It's also likely been fueled and accelerated by our rather routine vaccinating of adolescents and young adults against meningococcal disease.
In any event, cases have been diminishing, and to see this sudden jump in cases, particularly due to serogroup Y, is really quite unusual.
It's also unusual because meningococcal disease traditionally involves the very young — infants. The other age group that is usually affected is late adolescents and young adults. However, these cases are occurring in individuals who are predominantly middle aged — 30 to 60 years of age. That’s an unusual age group. It's also occurring prominently in people who are Black and those who have HIV. The last is something we've known about for a while — it's always been recommended that people with HIV infection get vaccinated — but the other demographic characteristics of middle age and Black patients, that's new.
We still don't understand why this is happening, but it's important that we know about it so that we can be much more aware in our own practices of this possibility.
Healio: What should clinicians be looking for?
Schaffner: Patients with meningococcal disease, as every doctor is taught in medical school, must be diagnosed early. The disease can manifest principally in two ways — central nervous system infection, or meningitis, an inflammation of the membranes that surround the brain and spinal cord; and through bloodstream infections. Both of these infections can move very rapidly from early symptoms into very severe illness.
One of the things that was mentioned in the CDC alert is the case fatality rate, which is 18%. That made me sit up. This is an often fatal illness. Mortality usually hovers around 10%, 11%, 12%, and for it to jump up to 18% is noteworthy. I'm speculating here, but that may have to do with diagnostic delays. Patients can present with “flu-like symptoms,” a sore throat, not feeling well, aches and pains, maybe a little bit of fever, and feeling very tired, and then they go to bed. And, my goodness, the next time somebody checks on them, you may find them comatose, or very, very ill, with blood pressure dropping. Being aware of this illness is very, very important.
Healio: What should clinicians do if they identify a case?
Schaffner: Obviously, diagnose and treat as quickly as possible because these patients almost invariably have to be admitted to the hospital and often to ICUs, but there are a couple of other things. One is to report it quickly to the local public health authorities. One of the things they will do — and physicians can help with this — is identify close contacts of the case, and then give them antibiotic prophylaxis in order to prevent them from getting sick.
Meningococci are carried in the nasopharynx, high up in the throat behind the nose, and are spread through very close contact with others, either through breathing or kissing or sharing things such as cigarettes and drinks. Identifying those contacts and making sure that they get brief courses of antibiotic prophylaxis is very important.
Healio: Do you have any tips about talking to patients about getting vaccinated?
Schaffner: It's important that parents make sure that adolescents and young adults who are going to college are vaccinated. On occasion — perhaps not in this particular circumstance but certainly in the past — there have been small outbreaks in colleges. As I said, young adults are particularly susceptible, especially residential students during their freshman year when they live in dorms and students who go to bars a lot or hang out at fraternity parties where there is drinking and sometimes smoking. Those are risk factors for the illness.
References:
- Increase in invasive serogroup Y meningococcal disease in the United States. https://emergency.cdc.gov/han/2024/han00505.asp. Published March 28, 2024. Accessed April 3, 2024.
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