Meningitis is a neurological condition in which the meninges, or the covering of the spinal cord and brain, become infected. The most common cause of meningitis is a viral infection, according to MedlinePlus, but meningitis can also be caused by bacteria. Bacterial meningitis can be deadly or cause significant damage to the brain.
Meningococcal meningitis is a severe and potentially fatal type of bacterial meningitis caused by the bacterium Neisseria meningitidis. Each year, about 1,500 people develop meningococcal meningitis, according to the National Meningitis Association.
Another type of bacterial meningitis is pneumococcal meningitis, caused by the bacterium Streptococcus pneumoniae. MedlinePlus stated that pneumococcal meningitis is the most common bacterial meningitis in adults, and it is the second most common among children older than 2 years of age.
H. influenzae meningitis used to be the most common bacterial meningitis in children younger than 5 years old before the creation of the vaccination, according to MedlinePlus. It currently occurs in less than 2 out of every 100,000 children. It is caused by the bacterium Haemophilus influenzae.
All three types of bacterial meningitis can be prevented with vaccinations. Two meningococcal vaccinations are available in the United States. They are meningococcal polysaccharide vaccine (MPSV4) and meningococcal conjugate vaccine (MCV4).
The two vaccines for pneumococcal meningitis are pneumococcal conjugate vaccine (PCV13) and pneumococcal polysaccharide vaccine (PPSV23). For H. influenzae meningitis, there is the Hib vaccine.
If an individual does not get these vaccines and contracts any of these types of bacterial meningitis, she may develop serious complications. For example, all three types of bacterial meningitis may cause brain damage, seizures, hearing loss, hydrocephalus and subdural effusion.
Another possible consequence of bacterial meningitis is lower achievement in school. A study conducted in Denmark followed 2,800 children who had been diagnosed with meningococcal, pneumococcal or H. influenzae meningitis between 1977 and 2007.