Measles is a highly contagious illness caused by the measles virus. Symptoms of measles appear about seven to 14 days after a person is infected with the virus. The illness typically begin with a high fever, coughing, a runny nose and red, watery eyes. Three to five days after the first symptoms begin, people with measles develop a rash that starts with flat red spots on the face that travel down the body. People with measles usually get a fever that spikes to over 104°F once the rash appears.
Measles can sometimes lead to ear infections, pneumonia, an upper airway infection that blocks breathing called croup, and diarrhea. Measles can also lead to more serious illness requiring hospitalization such as acute encephalitis (swelling of the brain) that can lead to brain damage, and in rare cases subacute sclerosing panencephalitis, a fatal degenerative disease of the central nervous system characterized by behavioral and intellectual deterioration and seizures that generally develop seven to ten years after measles infection.
Measles is fatal in one or two out of 1,000 children who become infected.
People are considered to be contagious from four days before to four days after the rash appears, although sometimes people with weakened immune systems do not develop the rash. Measles is one of the most contagious of all infectious diseases. Approximately nine out of ten people with close contact to a person with measles will develop the disease if they are not vaccinated. The virus is spread when an infected person breathes, coughs, or sneezes. Measles virus can remain infectious in the air for up to two hours after an infected person leaves an area.
If you have a high fever and a rash starting at the head and traveling down the body your health care provider may suspect you have measles, especially if you recently traveled internationally or were exposed to a person with a measles-like illness. Health care providers should report suspected measles cases to their local health department within 24 hours.
Laboratory confirmation is essential for all measles cases and all outbreaks. Your health care provider will obtain both a blood sample and a throat swab if they think you might have measles. Urine samples may also help detect the measles virus.
In 2000, measles was declared eliminated from the United States. However, measles cases and outbreaks still occur every year in the United States because measles is still commonly transmitted in many parts of the world, including countries in Europe, Asia, the Pacific, and Africa. Measles cases in the United States occur when people who were infected while in other countries spread the disease upon returning. Measles is more likely to spread and cause outbreaks in U.S. communities where groups of people are unvaccinated.
Measles can be prevented with measles-containing vaccine, usually as the combination measles-mumps-rubella (MMR) vaccine. The combination measles-mumps-rubella-varicella (MMRV) vaccine is given for children aged 12 months through 12 years for protection against measles, mumps, rubella and varicella. CDC recommends routine childhood immunization for MMR vaccine starting with the first dose at 12 through 15 months of age, and the second dose at 4 through 6 years of age or at least 28 days following the first dose.
Students in colleges or universities without measles immunity need two doses of MMR vaccine, with the second dose administered no earlier than 28 days after the first dose. People who are born during or after 1957 who do not have evidence of immunity against measles should get at least one dose of MMR vaccine.
People 6 months of age or older who will be traveling internationally should be protected against measles. Before travelling internationally, Infants 6 through 11 months of age should receive one dose of MMR vaccine. Children 12 months of age or older should have documentation of two doses of MMR vaccine (the first dose of MMR vaccine should be administered at age 12 months or older; the second dose no earlier than 28 days after the first dose) Teenagers and adults born during or after 1957 without evidence of immunity against measles should have documentation of two doses of MMR vaccine, with the second dose administered no earlier than 28 days after the first dose.
If you are exposed to measles and are not vaccinated, your health care provider will have you stay home from work or school and will provide the MMR vaccine. Except in health care settings, unvaccinated people who receive their first dose of MMR vaccine within 72 hours after exposure may return to childcare, school, or work. People who are at risk for severe illness and complications from measles, such as infants younger than 12 months of age, pregnant women without evidence of measles immunity, and people with severely compromised immune systems should be given immunoglobulin by their health care provider, which can help the body fight off the virus.