User:Mr. Ibrahem/Varicella vaccine

Varicella vaccine, also known as chickenpox vaccine, is a vaccine that protects against chickenpox. One dose of vaccine prevents 95% of moderate disease and 100% of severe disease. Two doses of vaccine are more effective than one, resulting in milder breakthrough disease if this occur. If given to those who are not immune within five days of exposure to chickenpox to prevent disease. Vaccinating a large portion of the population also protects those who are not vaccinated. It is given by injection just under the skin.

The World Health Organization (WHO) recommends routine vaccination only if a country can keep more than 80% of people vaccinated. If only 20% to 80% of people are vaccinated it is possible that more people will get the disease at an older age and outcomes overall may worsen. Either one or two doses of the vaccine is recommended. In the United States two doses are recommended starting at twelve to fifteen months of age. , twenty-three countries recommend all non-medically exempt children receive the vaccine, nine recommend it only for high risk groups, three additional countries recommend use in only parts of the country, while other countries make no recommendation. Not all countries provide the vaccine due to its cost.

Minor side effects may include pain at the site of injection, fever, and rash. Severe side effects are rare and occur mostly in those with poor immune function. Its use in people with HIV/AIDS should be done with care. It is not recommended during pregnancy; however, the few times it has been given during pregnancy no problems resulted. The vaccine is available either by itself or along with the MMR vaccine, in a version known as the MMRV vaccine. It is made from weakened virus.

Takahashi developed the first live attenuated varicella vaccine in 1974. GSK's Varilrix became commercially available in 1984, initially for high risk children, and then for healthy children in 1995. Merck's Varivax became available later in Europe. It is on the World Health Organization's List of Essential Medicines. In the United States it costs about 142 USD per dose as of 2020, though the US CDC can get it for about 110 USD. In some countries it is avaliable for about 17 USD as of 2013.