ArcaMax

DEAR DR. ROACH: Why aren't meningococcal vaccines recommended for people over the age of 23? Are they assuming (wrongly) that most people have already received them or that most won't (again, probably wrongly) be exposed?

When I worked in the emergency room long ago before there was a vaccine, we had two patients in a row die from meningococcal meningitis, and the entire staff that was on duty when they were brought in had to be treated prophylactically. Meningococcal meningitis terrifies me, and I was never vaccinated for it. According to the recommendations, I was already way over the age range when the vaccine came out. -- H.R.

ANSWER: Meningococcus (Neisseria meningitidis) is, indeed, a terrifying bacteria. Like you, I have seen people die within hours of its presentation. Even people who survive it may have long-term complications. I can understand wondering why there isn't a recommendation to vaccinate everyone against this disease.

A recommendation for a preventive maneuver such as a vaccination is made when the benefit is greater than the risk -- and when the cost of intervention is worth what society is willing to pay. In the case of the meningococcal vaccine, the vaccine is highly safe and effective. But because the disease is rare, it is only cost-effective when used in people who are at a high risk, either due to an increased likelihood of exposure or because of an increased risk of disease due to immune deficiency.

The vaccines (there are two separate vaccines; one for serogroups ACWY and another for serogroup B) are recommended for adolescents and young adults, especially when they are going to be living close together such as in a college dormitory, where there is a high risk of exposure.

Ideally, the first dose of MenACWY is given between ages 11-12, with a booster dose within five years of college entry. The MenB vaccine is given in two doses six months apart between ages 16-18. At the current time, MenACWY is recommended for all, while the recommendations for MenB are being discussed.

Apart from this recommendation, the vaccine is also given to people with HIV infections; those with no working spleens (due to surgery, sickle cell disease, or another cause); people who have a specific immune system problem (complement deficiency); and people who are on drugs that inhibit the complement system (such as eculizumab). Lab workers who are exposed to meningococcus are also recommended for vaccination.

The cost-effectiveness of meningococcal vaccination is low, meaning that it is very expensive to prevent a case even in college students -- on the order of $10 million to prevent one death. It would be much higher for healthy adults who are not living in a dormitory-type setting. This is because it is a rare disease, with approximately 1 case occurring per 400,000 people each year before the vaccine was recommended; more recent studies have shown that the incidence is now about 1 case per million people each year.

I made sure that my child was vaccinated for MenACWY and MenB before college as the cost of the vaccine was worth the peace of mind. I am not vaccinated myself as my risk has been very low since the vaccine was approved.

Because of the low prevalence of the disease (partially related to the success of the vaccine) and the high cost of the vaccine, it is not recommended for healthy adults. However, in the case of an outbreak, the vaccine may be recommended more generally by public health officials.

========

Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu.

(c) 2026 North America Syndicate Inc.

All Rights Reserved