Invasive meningococcal disease is a rare but serious infection caused by Neisseria meningitides, or meningococcus, bacteria. These bacteria can infect the protective membranes covering the brain and spinal cord (the meninges), leading to symptoms like fever, headache and a stiff neck.

Other symptoms include nausea and vomiting, sensitivity to light and mental confusion. This condition, known as meningococcal meningitis, can be fatal or lead to hearing loss and brain damage.

Invasive meningococcal disease can also lead to bloodstream infection (septicemia) that can also be fatal or require amputation of toes, fingers or limbs.

There are six meningococcal vaccines licensed in the U.S., but before you put your faith in one of them to protect yourself or your child from invasive meningococcal disease, it's important to be aware that they are far from fool proof.

Meningococcal B Vaccine Showed Limited Effectiveness During College Outbreak

The risk of meningococcal disease increases for those living in crowded or close quarters, including the military, prisons and also college campuses. Even then, however, this disease isn't spread as easily as you might think. According to the National Vaccine Information Center (NVIC):¹

"It is not easy to develop invasive meningococcal infection. You have to be susceptible and have regular close personal contact, such as sharing a toothbrush with or kissing a person who is colonizing meningococcal organisms."

In 2000, the U.S. Centers for Disease Control and Prevention (CDC) recommended that all college freshmen get a dose of meningococcal vaccine that contains four strains (A, C, W-35 and Y). In 2005, they also recommended that all 11-year-olds receive the vaccine.

However, strain B, a type not included in that vaccine, is associated with more than 50 percent of meningococcal cases and deaths. In children under the age of 5, strain B is responsible for up to 70 percent of the cases of meningitis.

In 2016, the U.S. Food and Drug Administration (FDA) approved a meningococcal vaccine including strain B, and now we have the results of how well it worked, or actually didn't work, on college campuses.

The vaccine (4CMenB) was administered during an outbreak at Princeton University in 2013 (before it was approved for use in the U.S.).

Out of the nearly 500 college students who received two doses of the vaccine, 34 percent had no immune response to the outbreak strain, according to a study published in The New England Journal of Medicine (NEJM).² The study authors noted:³

"This level of seropositivity was lower than expected, given the antigenic similarity between the outbreak strain and the components of the vaccine and given that the Meningococcal Antigen Typing System predicted that 4CMenB would induce responses against the outbreak strain."

Meningococcal Disease Is on the Decline in the U.S.

Rates of meningococcal disease in the U.S. are at a historic low. Cases decreased more than 60 percent from 1998 to 2007⁴ and, in 2013, the CDC reported there were about 550 total cases of meningococcal disease reported in the U.S., which is an incidence rate of 0.18 cases per 100,000 persons.⁵

In other words, meningococcal disease, and particularly infection with meningitis B, is relatively rare. In 2011, Barbara Loe Fisher, co-founder and president of NVIC, explained some of the concerns about adding meningococcal vaccines to the U.S. vaccine schedule.

It's true that the invasive meningococcal infection can be deadly; it's fatal in about 10 percent to 15 percent of cases. In about 11 percent to 19 percent of cases, long-term or permanent health problems, including loss of limbs, deafness, nervous system problems or brain damage will result.⁶

However, this is not a disease that's typically transmitted just by standing next to someone who has it.

Meningococcal bacteria cannot live outside the human body very long, so it's not as easily transmitted as, say, a cold virus. Infection occurs via the exchange of saliva, such as sharing a toothbrush or kissing — not from standing next to someone in an elevator.

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