Meningitis, the acute inflammation of the protective membrane around the brain and spinal cord, is most commonly caused by viruses and bacteria. The condition may be prevented with vaccination, good hygiene, and other preventive measures.

Viruses are the predominant cause of meningitis, including non-polio enteroviruses, measles, mumps, herpesviruses (including chickenpox and shingles), and even influenza viruses.

Bacterial meningitis, the second most common type, tends to be more severe and can lead to serious complications like brain damage, hearing loss, or learning disabilities. The five most common bacterial causes are Streptococcus pneumoniae, group B Streptococcus, Neisseria meningitidis, Haemophilus influenzae type b, and Listeria monocytogenes.

Identifying Risk Factors

Depending on the underlying cause of meningitis, some people may be at greater risk than others. Meningitis is usually caused by infections (bacterial, viral, fungal, parasitic), but it can also be the result of non-infectious causes such as inflammatory autoimmune diseases, drug reactions, or cancer.

Getting an infection (even ones strongly linked to meningitis) does not mean you will get meningitis. The same applies to non-infectious causes.

There are, however, risk factors that place you at increased risk of meningitis. Recognizing these risk factors help you build an individualized prevention strategy.

The risk factors for meningitis include:

  • Younger age, with infants, teens, and adults age 23 and under being at highest risk of bacterial meningitis
  • Older age, with people 65 and over at the highest risk of death from infectious meningitis
  • Living in crowded spaces, including dormitories, camps, and military installations where infections are more readily spread
  • Having a compromised immune system, such as occurs with organ transplant recipients, people with advanced HIV infection, and children with primary immunodeficiency (PID)
  • Being unvaccinated, most notably not receiving meningococcal vaccination

Vaccination

Vaccination remains crucial to the prevention of meningococcal disease caused by the bacteria Neisseria meningitides. When people talk about the “meningitis vaccines,” they are referring to a group of vaccines known as meningococcal vaccines. There are five meningococcal vaccines used in the United States that prevent one or more of five different serogroups (variations) of the bacteria.

Meningococcal conjugate vaccines protect against more common forms of the bacteria, namely serogroups A, C, W, and Y. Serogroup B meningococcal vaccines protect against serogroup B infection, the most frequent cause of meningococcal disease in the United States.

The five meningococcal vaccines licensed by the Food and Drug Administration are:

  • Menactra: serogroups A, C, W, and YMenveo: serogroups A, C, W, and YMenQuadfi: serogroups A, C, W, and YBexsero: serogroup BTrumenba: serogroup B

Meningococcal conjugate vaccines are recommended for all adolescents 11 to 12 years of age, with a second dose given at age 16. Serogroup B vaccines may be used in adolescents and young adults 16 through 23 who are at increased risk due to a meningitis outbreak or certain medical conditions.

Meningitis can occur as a complication of other infections, such as herpes zoster (shingles) and Haemophilus influenzae type b (Hib). Although there are vaccines that can prevent these infections (and, in turn, complications like meningitis), they aren’t regarded as “meningitis vaccines” per se.

Lifestyle 

The infectious organisms that cause meningitis are fairly common in the environment. They are readily transmitted by coughing, sneezing, kissing, and touching contaminated objects. 

To reduce your risk of meningitis, particularly if you are in a high-risk group:

  • Practice good hygiene. Routine handwashing and regularly disinfecting counters and surfaces are key to preventing many infections. This includes cleaning commonly-touched surfaces that are likely to host germs (called fomites).
  • Avoid close contact. Steer clear of friends, co-workers, or family members who are sick, and encourage them to stay at home and quarantine if necessary. This is especially true if there is an outbreak of infection in schools, universities, or the community at large.

Living in close quarters, such as residence halls or military barracks, can also create a hotbed of infections. While moving is not always possible, you should take extra precautions if you are immunocompromised, particularly during outbreaks of meningitis that frequently occur in colleges and universities.

Treatment

Meningococcal meningitis is treated with antibiotics as soon as the disease is suspected. Once a person is hospitalized, a broad-spectrum antibiotic is delivered by intravenous (IV) infusion. IV penicillin may also be used. A seven-day course is usually sufficient, although severe cases may require up to 21 days of treatment.

Unlike in universities, the rate of meningococcal meningitis in military installations is low due to the mandatory vaccinations of troops.

People who may have been exposed to N. meningitidis or who are at risk of being carriers should be given prophylactic (preventive) oral antibiotics to protect themselves and others. Those at risk include people living in the same household or anyone in direct contact with the infected person’s saliva (such as through kissing).

During an outbreak, meningococcal vaccination is recommended for anyone identified as being at risk. In places like universities, this may involve implementing a mass “opt-in” vaccination program.

A Word From Verywell

Meningitis has many different causes. The most serious causes can be prevented with vaccinations, good hygiene, and the avoidance of infection.

Oral antibiotics are recommended for anyone potentially exposed to Neisseria meningitides even if they have already received the meningococcal vaccine.

Meningitis Doctor Discussion Guide

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If meningitis does occur, either infectious or non-infectious, it is important to recognize the symptoms. Call your healthcare provider or seek emergency care if you experience any of the tell-tale signs, including:

  • Sudden high feverNeck stiffnessHeadache with nausea or vomitingConfusionExcessive sleepiness or difficulty wakingSensitivity to lightSeizures

Early diagnosis and treatment almost invariably lead to better outcomes.

Frequently Asked Questions

  • How do you prevent meningitis in babies?
  • If you’re pregnant, your healthcare provider should test you for group B strep (GBS) bacteria at 36 to 37 weeks, since one out of four women carry the bacteria. If you test positive, you’ll be given antibiotics during labor to make sure you don’t pass the bacteria to your baby. Vaccinations for diseases like measles, mumps, varicella zoster, and influenza can also protect babies from viral meningitis.
  • How is meningitis diagnosed?
  • Your healthcare provider will perform a physical exam to look for signs of meningitis. You may have tests to analyze your blood, urine, or mucus. A spinal tap may also be done to analyze your spinal fluid and confirm which type of bacteria are causing your illness.

If you’re pregnant, your healthcare provider should test you for group B strep (GBS) bacteria at 36 to 37 weeks, since one out of four women carry the bacteria. If you test positive, you’ll be given antibiotics during labor to make sure you don’t pass the bacteria to your baby. Vaccinations for diseases like measles, mumps, varicella zoster, and influenza can also protect babies from viral meningitis.

Your healthcare provider will perform a physical exam to look for signs of meningitis. You may have tests to analyze your blood, urine, or mucus. A spinal tap may also be done to analyze your spinal fluid and confirm which type of bacteria are causing your illness.