Meningitis is an inflammation of the meninges, the membranes covering the brain and spinal cord. There are several types of this disease, but the most common is viral meningitis, which occurs when a virus enters the body through the nose or mouth and travels to the brain. Bacterial meningitis is rare, but can be lethal. Although anyone can get it, the disease usually occurs in children and in people who have a hard time fighting infections. All types of meningitis are characterized by the presence of meningeal syndrome, which includes symptoms such as headache, vomiting, high fever, stiff neck, and generally feeling unwell; these symptoms occur three to six days after exposure to the bacteria or virus. Meningitis vaccine can be effective in preventing some bacterial infections that cause the disease.