Mumps
Mumps is a viral disease caused by the mumps virus. Initial signs and symptoms often include fever, muscle pain, headache, poor appetite, and feeling tired. This is then usually followed by painful swelling of one or both parotid salivary glands. Symptoms typically occur 16 to 18 days after exposure and resolve after seven to ten days. Symptoms in adults are often more severe than in children. About a third of people have mild or no symptoms. Complications may include meningitis (15 percent), pancreatitis (four percent), inflammation of the heart, permanent deafness, and testicular inflammation which uncommonly results in infertility. Women may develop ovarian swelling but this does not increase the risk of infertility.
Mumps is highly contagious and spreads rapidly among people living in close quarters. The virus is transmitted by respiratory droplets or direct contact with an infected person. Only humans get and spread the disease. People are infectious to each other from about seven days before the start of symptoms to about eight days after. Once an infection has run its course, a person is typically immune for life. Reinfection is possible but the ensuing infection tends to be mild. Diagnosis is usually suspected due to parotid swelling and can be confirmed by isolating the virus on a swab of the parotid duct. Testing for IgM antibodies in the blood is simple and may be useful; however, it can be falsely negative in those who have been immunized.
Mumps is preventable by two doses of the mumps vaccine. Most of the developed world includes it in their immunization programs, often in combination with measles, rubella, and varicella vaccine. Countries that have low immunization rates may see an increase in cases among older age groups and thus worse outcomes. There is no specific treatment. Efforts involve controlling symptoms with pain medication such as paracetamol (acetaminophen). Intravenous immunoglobulin may be useful in certain complications. Hospitalization may be required if meningitis or pancreatitis develops. About one per ten thousand people who are infected die.
Without immunization about 0.1 percent to one percent of the population are affected per year. Widespread vaccination has resulted in a more than 90 percent decline in rates of disease. Mumps is more common in the developing world where vaccination is less common. Outbreaks, however, may still occur in a vaccinated population. Before the introduction of a vaccine, mumps was a common childhood disease worldwide. Larger outbreaks of disease would typically occur every two to five years. Children between the ages of five and nine were most commonly affected. Among immunized populations often those in their early 20s are affected. Around the equator it often occurs all year round while in the more northerly and southerly regions of the world it is more common in the winter and spring. Painful swelling of the parotid glands and testicles was described by Hippocrates in the 5th century BCE.
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.