[7] Such care may include oral rehydration solution (slightly sweet and salty fluids), healthy food, and medications to control the fever.

[35] Modified measles is characterized by a prolonged incubation period, milder, and less characteristic symptoms (sparse and discrete rash of short duration).

[35] Complications of measles are relatively common, ranging from mild ones such as diarrhea to serious ones such as pneumonia (either direct viral pneumonia or secondary bacterial pneumonia), laryngotracheobronchitis (croup) (either direct viral laryngotracheobronchitis or secondary bacterial bronchitis), otitis media,[36] acute brain inflammation,[37] corneal ulceration (leading to corneal scarring),[38] and in about 1 in 600 unvaccinated infants under 15 months while more rarely in older children and adults, subacute sclerosing panencephalitis, which is progressive and eventually lethal.

[29][53] Humans are the only natural hosts of the virus, and no other animal reservoirs are known to exist, although mountain gorillas are believed to be susceptible to the disease.

[29][54] Risk factors for measles virus infection include immunodeficiency caused by HIV/AIDS,[55] immunosuppression following receipt of an organ or a stem cell transplant,[56] alkylating agents, or corticosteroid therapy, regardless of immunization status;[19] travel to areas where measles commonly occurs or contact with travelers from such an area;[19] and the loss of passive, inherited antibodies before the age of routine immunization.

[67][68] This method is not ideal, as saliva contains many other fluids and proteins which may make it difficult to collect samples and detect measles antibodies.

[67][68] Saliva also contains 800 times fewer antibodies than blood samples do, which makes salivary testing additionally difficult.

[69] In developing countries where measles is common, the World Health Organization (WHO) recommends two doses of vaccine be given, at six and nine months of age.

[52] Instead the medications are generally aimed at treating superinfections, maintaining good hydration with adequate fluids, and pain relief.

[52] Some groups, like young children and the severely malnourished, are also given vitamin A, which acts as an immunomodulator that boosts the antibody responses to measles and decreases the risk of serious complications.

[52][79][80] Treatment is supportive, with ibuprofen or paracetamol (acetaminophen) to reduce fever and pain and, if required, a fast-acting medication to dilate the airways for cough.

It typically occurs two days to one week after the measles rash breaks out and begins with very high fever, severe headache, convulsions and altered mentation.

[43] Measles is extremely infectious and its continued circulation in a community depends on the generation of susceptible hosts by birth of children.

Death rates during the outbreaks tend to be higher among poorer countries but middle income nations are also heavily impacted, according to the WHO.

[111] In November 2024, the WHO and CDC reported that measles cases increased by 20% last year, primarily due to insufficient vaccine coverage in the world’s poorest and conflict-affected regions.

[118] In 2019, the United Kingdom, Albania, the Czech Republic, and Greece lost their measles-free status due to ongoing and prolonged spread of the disease in these countries.

[127] In 2014, an outbreak was initiated in Ohio when two unvaccinated Amish men harboring asymptomatic measles returned to the United States from missionary work in the Philippines.

[128] Their return to a community with low vaccination rates led to an outbreak that rose to include a total of 383 cases across nine counties.

The Disneyland outbreak was held responsible for the infection of 147 people in seven U.S. states as well as Mexico and Canada, the majority of which were either unvaccinated or had unknown vaccination status.

[135] In 2018, one case occurred in Portland, Oregon, with 500 people exposed; 40 of them lacked immunity to the virus and were being monitored by county health officials as of 2 July 2018.

The outbreak was tied with population density of the Orthodox Jewish community, with the initial exposure from an unvaccinated child that caught measles while visiting Israel.

[149] Brazil won a measles elimination certificate by the Pan American Health Organization in 2016, but the Ministry of Health has proclaimed that the country has struggled to keep this certificate, since two outbreaks had already been identified in 2018, one in the state of Amazonas and another one in Roraima, in addition to cases in other states (Rio de Janeiro, Rio Grande do Sul, Pará, São Paulo and Rondônia), totaling 1,053 confirmed cases until 1 August 2018.

[153] In the Naga Self-Administered Zone in a remote northern region of Myanmar, at least 40 children died during a measles outbreak in August 2016 that was probably caused by lack of vaccination in an area of poor health infrastructure.

[156] A measles outbreak also happened among the Malaysian Orang Asli sub-group of Batek people in the state of Kelantan from May 2019, causing the deaths of 15 from the tribe.

[166] A precursor of the measles began causing infections in humans as early as the 4th century BC[167][168] or as late as after 500 AD.

[166] This agrees with the observation that measles requires a susceptible population of over 500,000 to sustain an epidemic, a situation that occurred in historic times following the growth of medieval European cities.

Two years later, measles was responsible for the deaths of half the population of Honduras, and it has ravaged Mexico, Central America, and the Inca civilization.

[21] In 1914, a statistician for the Prudential Insurance Company estimated from a survey of 22 countries that 1% of all deaths in the temperate zone were caused by measles.

[178] In 1954, the virus causing the disease was isolated from a 13-year-old boy from the United States, David Edmonston, and adapted and propagated on chick embryo tissue culture.

[189] The case received wide international coverage that prompted many to comment on it, including neurologist, well-known skeptic and science-based medicine advocate Steven Novella, who called Lanka "a crank".