Risk Factors for Meningitis
The primary risk factor for meningitis is a suppressed immune system, which may be caused by the following:
- Autoimmune disorders (e.g., lupus)
- Immunosuppressive drugs (e.g., corticosteroids, chemotherapies)
- Intravenous drug abuse
- HIV/AIDS, cancer, diabetes
- Removal of the spleen
Not receiving the mumps, Haemophilus influenzae type b, and pneumococcal (children aged 2 and younger) vaccines increases the risk for meningitis.
Age is also a risk factor for meningitis. It is more common in people younger than 5 years old and those older than 60. People between the ages of 15 and 24 who live in boarding schools and college dormitories are also at increased risk.
Living and working with large groups of people (e.g., military bases, child care facilities) increases the risk for infectious meningitis.
People who work with domestic animals (e.g., dairy farmers, ranchers) and pregnant women are at increased risk for meningitis associated with listeriosis (disease transmitted from animals to humans via soil). Listeriosis can be transmitted from mother to fetus through the placenta, causing spontaneous abortion. The disease is usually fatal in newborns.
Head injuries and brain surgery also put patients at risk for meningitis.