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. If given to those who are not immune within five days of exposure to chickenpox it prevents most cases of 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. As of 2012 most European countries either recommend it for all children or just those at high risk, but 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.
The chickenpox vaccine first became commercially available in 1984. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. In the United States it costs between 100 and 200 USD.
MMR vaccine
The MMR vaccine is a vaccine against measles, mumps, and rubella (German measles). The first dose is generally given to children around 9 to 15 months of age, with a second dose at 15 months to 6 years of age, with at least 4 weeks between the doses. After two doses 97% of people are protected against measles, 88% against mumps, and at least 97% against rubella. The vaccine is also recommended in those who do not have evidence of immunity, those with well controlled HIV/AIDS, and within 72 hours of exposure to measles among those who are incompletely immunized. It is given by injection.
The MMR vaccine is widely used around the world; with over 500 million doses having been given in over 100 countries as of 2001. Measles resulted in 2.6 million deaths per year before immunization became common. This has decreased to 122,000 deaths per year as of 2012, mostly in low income countries. Through vaccination, as of 2018, rates of measles in North and South America are very low. Rates of disease have been seen to increase in populations who go unvaccinated. Between 2000 and 2016, vaccination decreased measles deaths by a further 84%.
Side effects of immunization are generally mild and go away without any specific treatment. These may include fever, and pain or redness at the injection site. Severe allergic reactions occur in about one in a million people. The MMR vaccine is not recommended during pregnancy, however, may be given while breastfeeding. The vaccine is safe to give at the same time as other vaccines. Being recently immunized does not increase the risk of passing measles, mumps, or rubella on to others. Vaccination does not increase the risk of autism. The MMR vaccine is a mixture of live weakened viruses of the three diseases.
The MMR vaccine was developed by Maurice Hilleman. It was licensed for use by Merck in 1971. Stand alone measles, mumps, and rubella vaccines had been previously licensed in 1963, 1967, and 1969 respectively. Recommendations for a second dose were introduced in 1989. The MMRV vaccine which also covers chickenpox may be used instead. An MR vaccine, without coverage for mumps, is also occasionally used.