The course of meningitis often depends on your age, general health, and the organism causing the infection. The illness can range from mild to severe.

Viral meningitis is more common in the late summer and early fall. It usually does not cause serious illness. However, it is important to see your health professional if symptoms of meningitis develop so that he or she can rule out bacterial meningitis, which is more serious. With mild cases of viral meningitis, you may need only home treatment and can recover within 2 weeks. However, some people may feel light-headed and tired for several months after the illness.

Bacterial meningitis occurs most often from late winter to early spring. It usually causes serious illness and can be life-threatening. The symptoms of bacterial meningitis usually develop suddenly and last for 2 to 3 weeks. A person with bacterial meningitis is treated with antibiotics in a hospital.

Complications during illness and long-term complications are more common with bacterial than with viral meningitis. Newborns and young children with bacterial meningitis, people with impaired immune systems, and older adults with long-term medical conditions are more likely than others to develop immediate and/or long-term complications of meningitis.

People who have bacterial meningitis run the risk of death if they are not treated promptly. Newborns, children younger than 2, older adults, or people with weakened immune systems are at a greater risk of death than other people.

The likelihood of death from bacterial meningitis in adults is highest in those who are older than 50, have seizures during the first 24 hours of illness, delay getting treatment, are in a coma when admitted to the hospital, are in shock, or cannot breathe without help from a machine.² Most survivors recover completely.⁴

Meningitis caused by Streptococcus (S.) pneumoniae is more likely to cause death than meningitis caused by other bacteria.² Getting the pneumococcal conjugate vaccine (PCV)(What is a PDF document?) usually protects people from diseases (including meningitis) caused by most strains of the bacteria.