Meningitis refers to the inflammation of the meninges, the protective membranes that surround the brain and spinal cord. This condition can arise from various causes, with infections being the most common culprits. Among infectious causes, viruses frequently lead to this inflammation, resulting in what is known as viral meningitis. Viral meningitis is a common illness.
What is Viral Meningitis
Many different viruses can be responsible for viral meningitis, but non-polio enteroviruses are the most frequent cause in the United States. These viruses commonly reside in the intestines and can lead to mild symptoms like colds or stomach upsets. Other viruses, such as herpes simplex viruses, mumps, and measles, can also trigger viral meningitis.
Viral meningitis is generally considered less severe than bacterial meningitis, which is a more serious and potentially life-threatening form of the disease. While both types involve inflammation of the same membranes, the viral form typically has a milder course.
How Often Viral Meningitis Occurs
Viral meningitis is the most common type of meningitis globally and within the United States. Approximately 54.6% of all meningitis cases are viral, in contrast to bacterial infections, which account for about 21.8% of cases. This makes it significantly more prevalent than its bacterial counterpart, which sees around 4,100 cases annually in the U.S.
The incidence of viral meningitis is about 4.3 per 100,000 people based on 2018 data, with up to 75,000 cases of enteroviral meningitis reported annually in the United States. Furthermore, between 25,000 and 50,000 hospitalizations are linked to viral meningitis in the U.S. each year. Exact numbers are challenging because many mild cases do not require hospitalization or specific testing, leading to underreporting.
Who is Most Affected and Why
Children younger than 5 years old are particularly susceptible to viral meningitis, as are individuals with a weakened immune system. Infants younger than 1 month old are especially vulnerable and may experience more severe illness if infected.
The seasonality of common viral causes also influences who is affected. Enteroviruses, which are responsible for the majority of viral meningitis cases, are most prevalent during late summer and early fall in temperate climates. This seasonal pattern contributes to the higher incidence observed during warmer months.
Viruses causing meningitis primarily spread from person to person. Enteroviruses are often transmitted via the fecal-oral route, respiratory droplets, and contact with contaminated surfaces. While infection with these viruses is common, only a small fraction of infected individuals, fewer than one in 500 for enteroviruses, actually develop meningitis.
General Outlook and Recovery
Most cases of viral meningitis are generally mild and resolve on their own without specific medical treatment. Individuals typically recover within 7 to 10 days, though some may take up to a few weeks for full recovery. During this time, care primarily focuses on supportive measures, such as rest, maintaining hydration, and managing symptoms like fever and pain.
Hospitalization for viral meningitis is often for supportive care, as most viruses causing the condition do not have targeted treatments. Antiviral medications are typically reserved for specific viral causes, such as certain herpesviruses or influenza. While viral meningitis is rarely life-threatening, and most people recover without lasting complications, rare instances of severe effects can occur, particularly in very young children.