Measles is an acute viral respiratory illness caused by the measles virus, also called morbillivirus, that can result in severe complications and even death. While measles is one of the most contagious infectious diseases, it is also vaccine-preventable. Measles was declared eliminated from the United States in 2000, though cases and outbreaks still occur in every year. Information on the latest measles cases and outbreaks is available from the CDC.
Latest health alerts
- March 7, 2025: The CDC issued a Health Alert Network (HAN) on “Expanding Measles Outbreak in the United States and Guidance for the Upcoming Travel Season.”
Transmission
Measles is one of the most contagious diseases and is transmitted by direct contact with infectious droplet and also via airborne spread when an infected person breathes, coughs or sneezes. The virus can remain infectious in the air for up to 2 hours after an infected person leaves the area.
Signs & symptoms
Symptoms of measles typically begin 10-14 days after exposure, although some variation occurs. Early symptoms include fevers, malaise, and the three “C”s: cough, coryza (runny nose) and conjunctivitis. Koplik spots, small white spots on the inside of the cheeks, can occur as well. These early symptoms last about 4-7 days.
About 14 days after exposure, a macular rash appears. The rash typically starts around the hairline, spreading to the face, neck and down the body including the hands and feet. The rash lasts 5-6 days before fading.
Patients are contagious from 4 days before to 4 days after the rash appears.
Diagnosis
Measles is diagnosed using a nasopharyngeal swab, throat swab or urine specimen as well as serologic testing from all patients who have signs and symptoms suspicious for measles. As many of these samples as possible should be collected together to increase the likelihood of detecting the measles virus.
Prevention strategies
Vaccination
Humans are the only natural hosts of measles virus, making it a virus that can potentially be eliminated. CDC recommends two doses of measles-containing vaccine routinely for children, starting with the first dose at age 12 through 15 months and the second dose at age 4 through 6 years. This can be administered as the measles, mumps, rubella (MMR) or measles, mumps, rubella, varicella (MMRV) vaccine.
Adults should also be up to date on MMR vaccinations, unless they have other presumptive evidence of immunity. Adults with no evidence of immunity should get 1 dose of MMR vaccine. Vaccine efficacy is 93% after the first dose and reaches 97% with the second. “Booster” doses of MMR vaccine are not currently recommended for adults or children.
Treatment
There is no antiviral treatment for measles. It is important for patients to stay hydrated to replace fluids lost during diarrhea and vomiting. Patients with measles should receive 2 doses of vitamin A supplements given 24 hours apart. This restores low vitamin A levels that occur during the illness and can help prevent eye damage and blindness. There is some evidence that it improves mortality as well.
Infection prevention & control
Prompt identification and isolation of suspected measles is paramount in preventing spread within health care facilities. Ensuring all health care professionals have immunity will also reduce spread. Recommended Personal Protective Equipment (PPE) for measles is Standard + Airborne Precautions.
Complications
Blindness, encephalitis, diarrhea and associated dehydration, ear infections, and severe pneumonia are known complications. Before vaccination, measles was responsible for 48,000 hospitalizations yearly, with 1,000 people developing chronic disability. In addition, nearly 500 deaths were reported annually due to measles and its complications.
Additionally, a rare but fatal complication called subacute sclerosing panencephalitis (SSPE) can occur 7-10 years after someone survives a measles infection. SSPE is a degenerative central nervous system condition that includes behavioral and intellectual deterioration and seizures. SSPE is universally fatal.
Reporting
Measles is a nationally notifiable condition. Immediately notify state, tribal, local or territorial health departments (24-hour Epi On Call contact list) about any suspected case of measles to ensure rapid testing and investigation. States report measles cases to CDC.
Additional resources
CDC provides communications and public health resources about measles and the MMR vaccine.
