Taking stock of bacterial meningitis

In a recent article (N Engl J Med. 2011;364[21]:2016-2025), Thigpen et al report the results of 2 programs that conduct active surveillance for invasive bacterial disease, including meningitis, in the United States. Their data extend the report that documented a reduction of 55% in bacterial meningitis in all ages between 1986 and 1995 (Schuchat et al. N Engl J Med. 1997;337[14]:970-976).

Conjugated Hib vaccine largely was responsible for the previous decline, but since that report, other vaccines, including PCV7 and MCV4, have been added to the list of recommended immunizations for children. These vaccines have contributed to an additional significant fall in the incidence of bacterial meningitis, but the Thigpen article and the infant mentioned above demonstrate that there is more to be done.

Surely this is progress, but there also is evidence of a need for continued effort and new approaches. Although the median age for those affected by bacterial meningitis rose from 30.3 years to 41.9 years, the incidence in infants younger than 2 months did not decrease during the period under study, and group B streptococcus (GBS) remains the most common cause in this age group.

Eighty-six percent of the GBS meningitis cases among these infants had their onset after 7 days of life and would not have been affected by intrapartum antimicrobial prophylaxis. PCV7 has facilitated a decline of 92% in pneumococcal meningitis caused by vaccine serotypes and a 62% fall in the incidence of pneumococcal meningitis in 2- to 23-month-old children, but the incidence of infection due to nonvaccine serotypes rose during the surveillance period.

Although there is no vaccine available for prevention of infection due to Listeria monocytogenes, the incidence of meningitis because of that pathogen fell during the surveillance period by 36%, suggesting that efforts to reduce contamination of packaged foods and to educate pregnant women about high-risk foods have had a positive effect and should continue. And, despite the gains in prevention of bacterial meningitis, the fatality rate for those infected remains at 14.3%, not significantly different from the 15% rate in 1995.

Last month the Global Alliance for Vaccines and Immunisations announced commitments from 2 India-based pharmaceutical companies, as well as from Merck and GlaxoSmithKline, that they would provide some vaccines at reduced prices to developing countries. Complete protection from bacterial meningitis has not yet been achieved in the developed world, but surveillance data provides guidance for continued progress. Greater availability of vaccines may someday allow all the children of this planet to benefit from the same protection that is available to children in the United States.

DR MCMILLAN
Editor-in-Chief
Contemporary Pediatrics