User:Mr. Ibrahem/Measles vaccine

Measles vaccine is a vaccine that prevents measles. Nearly all of those who do not develop immunity after a single dose develop it after a second dose. When rates of vaccination within a population are greater than 92%, outbreaks of measles typically no longer occur; however, they may occur again if rates of vaccination decrease. The vaccine's effectiveness lasts many years. It is unclear if it becomes less effective over time. The vaccine may also protect against measles if given within a couple of days after exposure to measles.

The vaccine is generally safe, even for those with HIV infections. Most children do not experience any side effects. Side effects if they do occur are usually mild, such as fever, rash, pain at the site of injection, and joint stiffness; and are short lived. Anaphylaxis has been documented in about 3.5–10 cases per million doses. Rates of Guillain–Barré syndrome, autism and inflammatory bowel disease do not appear to be increased by measles vaccination.

The vaccine is available both by itself and in combinations such as the MMR vaccine (a combination with the rubella vaccine and mumps vaccine) or the MMRV vaccine (a combination of MMR with the chickenpox vaccine). The measles vaccine is equally effective for preventing measles in all formulations, but side effects vary depending with the combination. The World Health Organization (WHO) recommends measles vaccine be given at nine months of age in areas of the world where the disease is common, or at twelve months where the disease is not common. Measles vaccine is based on a live but weakened strain of measles. It comes as a dried powder which is mixed with a specific liquid before being injected either just under the skin or into a muscle. Verification that the vaccine was effective can be determined by blood tests.

In 1963, the Edmonston-B strain of measles virus was turned into a vaccine and licensed in the United States. In 1968, an improved and even weaker measles vaccine began to be distributed and has been the only measles vaccine used in the United States since 1968. About 85% of children globally have received this vaccine as of 2013. In 2015, at least 160 countries provided two doses in their routine immunization. The measles vaccine was first introduced in 1963. It is on the World Health Organization's List of Essential Medicines. The wholesale cost in the developing world is about 0.70 USD per dose as of 2015. As outbreaks easily occur in under-vaccinated populations, the disease is seen as a test of sufficient vaccination within a population.