Meningococcal vaccine

Meningococcal vaccine refers to any of the vaccines used to prevent infection by Neisseria meningitidis. Different versions are effective against some or all of the following types of meningococcus: A, B, C, W-135, and Y. The vaccines are between 85 and 100% effective for at least two years. They result in a decrease in meningitis and sepsis among populations where they are widely used. They are given either by injection into a muscle or just under the skin. Meningococcal vaccine refers to any of the vaccines used to prevent infection by Neisseria meningitidis. Different versions are effective against some or all of the following types of meningococcus: A, B, C, W-135, and Y. The vaccines are between 85 and 100% effective for at least two years. They result in a decrease in meningitis and sepsis among populations where they are widely used. They are given either by injection into a muscle or just under the skin. The World Health Organization recommends that countries with a moderate or high rate of disease or with frequent outbreaks should routinely vaccinate. In countries with a low risk of disease, they recommend that high risk groups should be immunized. In the African meningitis belt efforts to immunize all people between the ages of one and thirty with the meningococcal A conjugate vaccine are ongoing. In Canada and the United States the vaccines effective against all four types of meningococcus are recommended routinely for teenagers and others who are at high risk. Saudi Arabia requires vaccination with the quadrivalent vaccine for international travelers to Mecca for Hajj. Meningococcal vaccines are generally safe. Some people develop pain and redness at the injection site. Use in pregnancy appears to be safe. Severe allergic reactions occur in less than one in a million doses. The first meningococcal vaccine became available in the 1970s. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. The wholesale cost in the developing world is between US $3.23 and $10.77 per dose as of 2014. In the United States it costs $100–200 for a course. Neisseria meningitidis has 13 clinically significant serogroups, classified according to the antigenic structure of their polysaccharide capsule. Six serogroups, A, B, C, Y, W-135, and X, are responsible for virtually all cases of the disease in humans.