Serogroup B Meningococcal Vaccine Approved But Awaiting CDC Recommendations
Oct 30, 2014
This month another college student succumbed to a strain of meningitis that is not covered in the currently recommended meningococcal vaccine. In 2013 and 2014 outbreaks of serogroup B meningococcal disease occurred at Princeton University and University of California’s Santa Barbara (UCSB) campuses, prompting health officials to request special permission from the Food and Drug Administration to utilize a vaccine that is not currently licensed in the United States. More than 5,000 Princeton University students received the first dose of the MenB vaccine in December 2013, and more than 4,700 students received the second dose in February 2014. At UCSB, as many as 9,000 students received the first dose in February and March 2014 and more than 7,000 received the second dose in April 2014.
While some questioned the wisdom of using a vaccine that had yet to be licensed here in the U.S., clinical trials in other countries have shown that the same vaccine met safety and efficacy standards that cleared the way for licensure in the European Union, Canada, and Australia back in 2013. More than one million doses of the vaccine have since been distributed to over 30 countries where the vaccine was licensed, with little to no sign of serious adverse events. And, it has been determined that there have been no unusual patterns or occurrence of serious reactions reported among the students vaccinated here in the U.S.
Two different manufacturers (Pfizer and Novartis) have sought FDA approval of their MenB vaccines. Yesterday Pfizer received final approval and Novartis will be informed regarding the FDA’s decision in the next few months. In anticipation, the CDC’s Advisory Committee on Immunization Practices (ACIP), a group of medical and public health experts that develop vaccine recommendations to help control diseases in the U.S., has been receiving reports from their meningococcal subcommittee. This subcommittee is tasked with investigating the epidemiology of this disease and the results of the clinical trials. These reports become critical in helping the ACIP to ultimately vote on whether the vaccines will be recommended to the public once approved and under what parameters.
Of course, this will be no easy job. It’s important to understand that there are five main serogroups (“strains”) of meningococcal bacteria: A, B, C, Y, and W. The most common ones that cause disease in the United States are B, C, and Y. Our current U.S. meningococcal vaccine covers the A,C, Y and W strains, but not serogroup B. The strain prevalence often varies by country. For instance, Australia and Europe see far more cases of serogroup B than we do here in the U.S. However, in 2012, there were about 500 total cases of meningococcal disease in the U.S, and 160 of those cases were caused by serogroup B. According to a presentation made at today’s ACIP meeting, in the years spanning from 1998-2012 there have been an average of 50 cases of serogroup B meningococcal disease per year in 18-24 year olds. When factoring in the recent outbreaks, serogroup B now causes 40% of all meningococcal disease cases among 11-24 year olds.
While statistically speaking, an average of 50 cases a year may not sound like a lot, how can one quantify the number of deaths, and life-long disabilities caused by meningococcal disease that is considered acceptable?
Unfortunately, while meningococcal disease may not be highly prevalent, the disease can result in devastating consequences. Jessica MacNeil, who presented the epidemiology data on behalf of the CDC at this morning’s ACIP meeting, noted that there is a 12.4% fatality rate for serogroup B meningococcal disease.
A common outcome of meningococcal infection is meningitis, in which a bacterium infects the protective membranes covering the brain and spinal cord. Symptoms typically develop quickly and, in fatal cases, deaths can occur in as little as a few hours. In non-fatal cases, permanent disabilities can include hearing loss and brain damage. Another common outcome is bloodstream infection in which the bacteria enters the bloodstreams and multiplies, damaging the walls of the blood vessels and causing bleeding into the skin and organs. This type of infection is also very serious and again fatality can occur in as little as a few hours. In non-fatal cases, permanent disabilities can include amputation of toes, fingers, or limbs and severe scarring as a result of skin grafts.
Having the privilege of knowing some very courageous and inspirational survivors of meningitis, I would say that as a parent I want to do all I can to protect my children from this disease. Knowing that a vaccine is now licensed makes me eager to know how soon it will be available and what the ACIPs recommendations will be.
Just this summer, before my oldest daughter headed to college, I made sure she had her meningococcal booster (which covers the A, C, Y and W strains). However, with the ongoing outbreaks in university settings, I worry that she is not yet protected against the serogroup B strain. But it’s not just about my college-aged daughter. I have four others I want to protect. And I know lots of parents who would want to do the same. Unfortunately, there are many parents who don’t realize that the current meningococcal vaccine leaves their children susceptible to the serogroup B strain. And even some parents who are not aware of the current vaccine and the fact that it is recommended for all children between the ages of 11-12, with a booster shot at age 16. This is why I’ve been following the ACIP’s discussion of the new serogroup B vaccine for some time.
It appears that at the February 2015 ACIP meeting the committee will be discussing the use of MenB vaccine in persons 10 years of age and older for those with high-risk medical conditions, microbiologists and to address ongoing outbreaks. There is a planned vote on recommendations specifically for high risk groups. Then, at their upcoming June and October 2015 meetings, they will review the evidence for recommending the vaccine for expanded target groups, while also reviewing the economic and impact analysis.
While today’s ACIP presentation resulted in many answers, it also prompted more questions for me:
Does the prevalence of the serogroup B strain necessitate a vaccine recommendation for all children, or just for those people considered high risk? And, knowing that there have been, on average, about 50 cases per year in the 18-24 age group, will this age group be considered high risk?
Since 1/3 of the cases of MenB are among college students, will college students be considered in the high risk category? If so, aren’t we missing the opportunity to protect the remaining 2/3 of 18-24 year olds who appear to also be at risk, though not attending college?
Additionally, if the vaccine is recommended only for use in high risk and outbreak situations, it’s quite possible that a severe case or death will have to occur before the outbreak recommendation is implemented. In those instances, how will immunization efforts be coordinated in response to these outbreaks? In the cases of Princeton and UCSB, the universities paid for and facilitated mass vaccination clinics. Will the universities be expected to take responsibility, or will parents need to coordinate the receipt of the vaccine for their children independently?
While the current adolescent schedule includes meningococcal vaccine that is administered initially between the ages of 11-12, followed with a booster dose at 16 along with their Tdap booster and HPV vaccine series, the new MenB vaccine will be administered as a separate vaccine requiring multiple doses for optimal immunity. How will this additional vaccine be incorporated into the current immunization schedule and what steps will be taken to ensure parents and providers are aware of the changes to the schedule? At today’s meeting, Cynthia Pellegrini, a current member of the Adolescent Immunization Working Group, urged the committee to make a recommendation that aligns with the current adolescent schedule, prompting me to consider just how complicated the delivery of vaccines can be with the varied age recommendations.
Even though one of the MenB vaccine has been approved, there are still some questions as to how parents can get their children vaccinated prior to formal ACIP recommendations. I plan to continue to follow the ongoing discussions of the MenB vaccine and the ACIP’s efforts to prevent additional cases of such a debilitating disease. If you have further questions for consideration, please add them to the comments below so we can work to address them in follow-up posts.
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