Sharp Drop in Invasive Meningococcal Disease Underscores Importance of Vaccination

A health system in Spain saw a significant decrease in cases of invasive meningococcal disease (IMD) between 1977 and 2013, suggesting vaccination against serogroup C meningococci has been effective, according to a new study.

Published by Oxford University Press on behalf of the Infectious Diseases Society of America, the study included 527 cases of IMD at the Hospital Universitari de Bellvitge in Barcelona, Spain, between 1977 and 2013, comparing those diagnosed with sepsis with those diagnosed with meningitis along with varying degrees of sepsis.

The observational study highlighted the significance of meningococcal disease, which has an overall mortality of 5% to 16%, and exhibits ongoing changes in incidence rates and prevailing serogroups. Serogroup C was the last epidemic outbreak of the disease in Spain, which occurred in the mid-1990s. Since that time, a vaccine targeting group C was introduced.

Rates of IMD fell dramatically during the study period, with 67% occurring during the first quarter of the study period and 4% during the last quarter.

The study included 57 cases of sepsis and 470 cases of meningitis and found that cases with only sepsis showed the highest rate of mortality. Thirty-three patients out of 527 cases died, including 8 with sepsis and 25 with meningitis.

Dexamethasone used before antibiotics was found to be safe and showed the ability to prevent some arthritis episodes.

Prophylactic phenytoin may be effective for selected populations, such as the elderly or those with previous brain infarction or lesions, and could possibly reduce the risk of seizures. Used in severe cases, none of the patients who received prophylactic phenytoin experienced seizures.

The importance of responding quickly at the onset of the disease with antibiotics was highlighted by the study.

"Besides vaccination, which is the key method for prevention, early recognition and aggressive treatment are the only effective measure against this invasive disease," the investigators wrote in the report. "The immediate administration of antibiotic therapy, and recognition and treatment of patients who may have complication of IMD such as shock, raised intracranial pressure or both, are required in order to prevent death."

Recent focus has shifted to serogroup B, which now makes up most of the cases in Spain and was responsible for 76% of the cases in the study.

"It's important to remember in general that meningococcal meningitis is a very serious disease," Amesh Adalja, MD, senior scholar at John's Hopkins Center for Health Security and spokesman for the Infectious Diseases Society of America, told Contagion^®.

The study offered takeaways for understanding the disease beyond its cohort. Dr. Adalja said that the fact that the study specifically called out the prevalence of serogroup B suggests a need for rethinking vaccine policy in the United States. Two vaccines are available for group B, but are not part of routine vaccination recommendations.

"There has been some controversy about the recommendation not being strong enough," Dr. Adalja said.

In April 2018, the US Food and Drug Administration granted Breakthrough Therapy designation to Pfizer Inc.’s meningococcal group B (MenB) vaccine, Trumenba, for children. Trumenba became the first approved MenB vaccine in 2014 and was recommended to be administered to about 35,000 people at Rutgers University in New Brunswick, New Jersey, after 2 students were diagnosed with serotype B meningococcal disease in 2016. Another New Jersey institution, Princeton University, saw an outbreak of the disease in 2013-14, when 9 cases associated with the university were reported.