Bacterial Meningitis Prevention

In 2005, the Centers for Disease Control and Prevention (CDC) recommended the conjugate meningococcal vaccine for all adolescents (all children between 11 and 13 years of age). At the time, it was anticipated that the vaccine immunity and vaccine effectiveness would last for 10 years, so this would last through adolescence and the first year of college (during which there’s clearly increased risk for invasive meningococcal disease). However, that assumption was wrong in several ways. First, immunity does appear to decline after 5 years, earlier than had been suspected. Secondly, if you look at vaccine effectiveness, within a year of getting the vaccine, it’s in the low 90% range, within 1 to 2 years of receiving the vaccine, it’s also in the low 90% range, but when you look between 2 to 5 years after vaccination, although the numbers are fairly low and the confidence intervals are wide, it looks like the protection drops into the low 50% range. Similarly, some evidence for herd immunity was expected, as had been seen for the conjugate Haemophilus influenzae type-B vaccine and the conjugate pneumococcal vaccine, but that didn’t appear to be happening. It appears that the vaccine is protecting only those who are vaccinated and not extending beyond that group. For that reason, members of the Advisory Community for Immunization Practices (ACIP) considered at their last meeting in October whether they should change the recommendation, and they did. The recommendation was changed by keeping the current recommendation in place (where adolescents receive the vaccine between 11 and 13 years of age) and adding a booster at 16 to 18 years of age, roughly 5 years later, to make sure that they’re still protected through adolescence (11, 12, 13, 14, and 15 years) and also through the early years of college. It was a close vote. The vote was only 6 to 5 in favor of the booster. Those who opposed it saw it solely as a financial question: “Do we really have enough money in the system to pay for that extra dose?” What is unfortunate here is that, when we consider these things at the CDC, we’re often comparing the cost/benefit ratios of 1 vaccine with another. It would be more appropriate to consider the cost/benefit ratios of vaccines [in comparison with] other preventive healthcare interventions, such as mammography or prostate cancer screening, in which case you’d find that vaccines fare quite well. In any case, the take-home message is that there is now a booster recommendation for the conjugate meningococcal vaccine. Thanks for your attention.