Measles

Rubeola

The History of Measles

Measles has been with us for a very long time. It has caused deadly outbreaks, inspired scientific discoveries, and led to one of the great public health successes of the 20th century.

The first clear written description of measles as its own disease came from the Persian physician , known in the West as Rhazes. Around the year 900, he wrote a book that explained how to tell measles apart from smallpox. He described the rash and the cough, runny nose, and red eyes that still define measles today.

Where did measles come from? Studies of the virus's genes show that , a cattle virus that is now extinct (through the use of vaccination of cattle, coincidentally). The two viruses split apart as early as the 6th century BCE. That is about the time when human cities first grew big enough to keep the virus going from person to person. Measles needs a steady supply of people who have never had it, so it is a disease of crowded human populations.

Measles Meets New Populations

Measles was most deadly when it reached people who had never been exposed to it before. A few examples:

• Faroe Islands (1846): A Danish doctor named Peter Panum studied an outbreak on these remote islands. . Panum's careful notes taught doctors that measles spreads from person to person, that it takes about two weeks to show up after exposure, and that people who had it as children were still protected decades later.

• Hawaii (1824 and 1848): In 1824, King Kamehameha II and Queen Kamamalu traveled to London. . Measles did not reach the Hawaiian Islands until 1848. That year, measles, whooping cough, dysentery, and influenza arrived one after another. Together, these epidemics killed .

• Fiji (1875): Measles arrived on a British warship , where the disease was circulating. In just four months, . Some estimates put the toll at a quarter to a third of the population.

Measles in the Army

During World War I, measles swept through crowded U.S. Army training camps. Young recruits from farms and small towns had never been exposed to it. , mostly from pneumonia. Army doctors learned hard lessons about crowding, quarantine, and secondary infections. Those lessons helped shape the response to the 1918 influenza pandemic that followed.

Measles in the United States Before the Vaccine

Before 1963, almost every child in the United States caught measles by age 15. Each year, . Among the cases that were reported, about 400 to 500 people died, 48,000 were hospitalized, and 1,000 developed encephalitis (swelling of the brain). In the first decade after measles became a reportable disease in 1912, .

Scientific Breakthroughs and Vaccine Development

The path to a vaccine began in a Boston laboratory. In 1954, from the blood of a 13-year-old student named David Edmonston. Enders had already won a Nobel Prize for growing poliovirus in the lab. His team used the same methods to grow the measles virus and then weaken it so it could be used as a vaccine.

Key milestones:

• 1963: The first measles vaccines were licensed in the United States. There were . The killed vaccine did not work well and was withdrawn in 1967. The Edmonston B vaccine worked, but it often caused fever and rash.
• 1968: . This strain, called Edmonston-Enders (or "Moraten"), caused fewer side effects. It is .

• 1971: The was licensed. Three shots became one.
• 1989: After outbreaks among vaccinated school children, experts for all children. Two doses give better, longer-lasting protection.
• 2000: The United States . This means the virus was no longer spreading inside the country for 12 months or more. New cases only came from travelers.
• 2005: The , which adds chickenpox (varicella) protection, was licensed.
• 2022: The FDA approved , a second MMR vaccine brand, giving the United States two MMR vaccine options.

Scientists keep working on new ways to deliver the vaccine. A was tested in infants and toddlers in The Gambia in 2024. It worked as well as the regular shot. Patches do not need refrigeration in the same way and could be given by people with less training, which could help reach children in hard-to-reach places.

What the Vaccine Has Done

The results have been enormous. Worldwide, . Global measles deaths fell by 88% during that time, from about 780,000 a year to about 95,000.

Even so, the job is not finished. In 2024, only . Stopping measles needs at least 95% coverage with two doses. More than 30 million children were under-protected in 2024.

Measles as a Disease

Measles is caused by the measles virus, a member of the Paramyxoviridae family. It is one of the most contagious diseases known. It spreads through the air when an infected person coughs, sneezes, or just breathes. The virus can after that person has left the room.

Scientists use a number called R₀ ("R-naught") to measure how contagious a disease is. It is the average number of people one sick person will infect if no one around them is immune. For measles, . For comparison, .

A person with measles is . That means people spread measles before they even know they have it.

Symptoms

Symptoms usually start . Measles comes in stages:

• First, it looks like a bad cold: High fever (often over 104°F), cough, runny nose, and red, watery eyes. This lasts about 4 to 7 days.
• Then, spots in the mouth: are tiny white dots on the inside of the cheeks. They show up a day or two before the rash and are a telltale sign of measles.
• Finally, the rash: Flat red spots appear on the face and at the hairline, then spread down to the neck, chest, arms, and legs. The fever often spikes as the rash spreads. The rash lasts about 4 to 8 days and then fades.

Complications

Many people recover from measles, but it is not a harmless childhood illness. According to the :

• About 1 in 5 unvaccinated people in the United States who get measles ends up in the hospital.
• About 1 in 10 children with measles gets an ear infection, which can cause permanent hearing loss.
• As many as 1 in 20 children with measles gets pneumonia. This is the most common cause of measles deaths in young children.
• About 1 in 1,000 children with measles develops encephalitis (brain swelling), which can cause seizures, deafness, or intellectual disability.
• 1 to 3 in 1,000 children who get measles die from it.
• Measles during pregnancy raises the risk of premature birth and low birth weight.

Two complications deserve special attention:

Immune amnesia: Measles does not just make you sick for a week or two. It can erase part of your immune system's memory. A 2019 study found that measles . This leaves children open to infections they used to be protected from, for months or even years afterward. The MMR vaccine does not do this.

SSPE: is a rare but always-fatal brain disease. It appears 7 to 10 years after a measles infection, when the person seems to have fully recovered. Among people who had measles during the 1989–1991 U.S. outbreak, . The risk is higher for children who get measles before age 2.

Treatment

There is . Doctors treat the symptoms and watch for complications:

• Supportive care. Rest, fluids, and fever control. Antibiotics are used if a bacterial infection like pneumonia or an ear infection develops.
• Vitamin A. The World Health Organization recommends . Measles uses up the body's vitamin A, and low levels raise the risk of eye damage and death, especially in children who are malnourished. In the United States, the CDC and the American Academy of Pediatrics say .
• Vitamin A does not prevent measles. It is not a substitute for vaccination. During the 2025 West Texas outbreak, some parents gave their children large doses of vitamin A at home. , including signs of liver damage. Too much vitamin A can harm the liver, bones, and brain.
• Isolation. People with measles should .

If you have been exposed and are not immune, there is a short window to act. can prevent measles or make it milder. For babies, pregnant people, and people with weak immune systems, a shot of immune globulin (ready-made antibodies) can be given within 6 days of exposure.

Measles in the 2020s: A Resurgence

Why It Came Back

For a while, it looked like measles might be on its way out. Then several things happened at once.

The Wakefield fraud: In 1998, Andrew Wakefield and colleagues published in The Lancet that falsely claimed the MMR vaccine was linked to autism. The study looked at . Investigators later found that Wakefield had . His and The Lancet retracted the paper in 2010. Many large studies since then have found no link between MMR and autism, including . But the fear it created has never fully gone away.

The COVID-19 pandemic: Routine childhood vaccination fell behind around the world during 2020 and 2021. Many countries also postponed the large catch-up campaigns that normally fill gaps in coverage.

Falling vaccination rates: In the United States, MMR coverage among kindergartners dropped from . The share of kindergartners with a vaccine exemption reached . National averages also hide pockets where coverage is far lower. Measles finds those pockets.

The World

In 2024, there were , about 800,000 more than before the pandemic. An estimated 95,000 people died, most of them children under 5. had large or disruptive outbreaks, nearly triple the number in 2021. Europe and Central Asia reported , the most since 1997.

Samoa, 2019: What Happens When Vaccination Stops

Samoa is a Pacific island nation of about 200,000 people. In July 2018, . The vaccine itself was not the problem. Nurses had mixed it with an expired muscle relaxant instead of sterile water. The two nurses were sent to prison. But the deaths frightened parents, and the government while it investigated.

Anti-vaccine activists, including Robert F. Kennedy Jr., visited Samoa in 2019 and . By the time measles arrived in late 2019, .

The result was a disaster. In about three and a half months, , most of them children under 5. Nearly 1,900 people were hospitalized. The government declared a state of emergency, closed schools, and made vaccination mandatory. On December 5 and 6, 2019, so that mobile teams could go door to door. Families were told to hang red flags outside homes where someone still needed a shot. The campaign pushed coverage back above 95%, and the outbreak ended in January 2020.

The Americas Lose Elimination Status

The Americas were , first in 2016 and again in 2024 after outbreaks in Venezuela and Brazil were brought under control. That ended on November 10, 2025, when the Pan American Health Organization (PAHO) announced that . The reason was Canada, where an outbreak that began in October 2024 had spread for more than 12 months and caused more than 5,000 cases.

Mexico has been hit hard too. The virus crossed the border from Texas into Chihuahua in early 2025. By May 2026, Mexico had recorded . By mid-2026 the Americas as a whole had reported , the most since 2004.

The United States, 2025 and 2026

2025: In January 2025, measles began spreading in a close-knit, under-vaccinated community in Gaines County, West Texas. The outbreak grew to and spilled into New Mexico, Oklahoma, and beyond. . They were the first measles deaths in the United States in a decade. Texas declared the outbreak over in August 2025, but by then the virus had seeded new outbreaks in Utah, Arizona, and South Carolina. For the full year, the United States recorded , the most since 1992.

2026: The situation got worse. As of October 8, 2026, the CDC had counted in 47 states and jurisdictions, with 42 new outbreaks. That is the most cases in a single year since the 1989–1991 resurgence, when were reported. About , and about . More than .

The biggest outbreaks:

• South Carolina: From October 2025 to March 2026, the Upstate region had , at the time the largest single U.S. outbreak in about 30 years.
• Utah and Arizona: An outbreak that started in June 2025 has infected and spread across the state line into northern Arizona.
• Pennsylvania: An outbreak that began in late April 2026 became the largest in the state in decades. By October 7, 2026, , with more than 200 people hospitalized. The state has reported . The first two, announced in August 2026, were who were too young to be vaccinated. These were the first measles deaths in Pennsylvania in 35 years.
• New York: On October 5, 2026, Governor Kathy Hochul as cases spread in rural counties bordering Pennsylvania.

The national death count is still being sorted out. As of October 2026, the CDC and says the number may change as death records are reviewed. Pennsylvania alone has reported five. The CDC is working with state epidemiologists on a standard definition for counting measles deaths.

Elimination status: The United States has held measles elimination status since 2000. To keep it, a country must show that no single chain of transmission has lasted 12 months or more. Because the Texas outbreak's virus kept spreading into Utah, Arizona, and South Carolina, the U.S. status is now in question. PAHO was going to review it in April 2026 but . Canada already lost its status in November 2025.

Bangladesh, 2026: The World's Largest Outbreak

In March 2026, Bangladesh recognized a measles outbreak that had been building since late 2025. It grew into . From March 15 through September 13, 2026, the country reported . About 81% of patients were children under 5. The outbreak reached all 64 districts, with the worst spread in the crowded informal settlements of Dhaka.

Bangladesh's story shows how quickly progress can unravel. The country had raised measles vaccine coverage from 2% in the late 1970s to . Then several things went wrong at once. The last nationwide catch-up campaign was in 2020, and the one planned for 2024 was postponed. Political upheaval in 2024 disrupted health services. A change in how vaccines were purchased led to . Assessments found that .

The response was large. The government launched an emergency vaccination campaign in April 2026, first in 18 high-burden districts and then nationwide, . Hospitals gave vitamin A to all measles patients and expanded isolation wards.

What These Outbreaks Have in Common

Samoa, Bangladesh, and the United States are very different places. But their outbreaks share a pattern:

1. A gap opens. Vaccination drops because of a scare, a supply problem, a pandemic, or a loss of trust.
2. Susceptible people pile up. For a few years, nothing seems to happen. Children who missed their shots grow older. The gap gets bigger.
3. The virus arrives. One traveler brings measles in. In a well-vaccinated community, it goes nowhere. In a community with a gap, it explodes.
4. The youngest pay the price. Babies under 12 months are too young for the vaccine. They depend on everyone around them being immune. In every one of these outbreaks, infants were among those who died.

The Role of Vaccination in Prevention

Vaccination is the only reliable way to prevent measles. ; one dose is about 93% effective. Protection is long-lasting. When , measles cannot spread easily, and that protects people who cannot be vaccinated, including newborns and people with weakened immune systems.

What keeps measles away:

• Routine childhood vaccination with two doses of MMR: the first at 12–15 months and the second at 4–6 years.
• Catch-up doses for older children and adults who missed them or are not sure of their status.
• Early doses during outbreaks or before travel. before international travel, and health departments may recommend it during local outbreaks. They still need the two routine doses later.
• Strong surveillance so outbreaks are caught early.
• Trustworthy information that answers people's questions honestly.

Conclusion

Measles has been with humanity for more than a thousand years. For most of that time, there was nothing anyone could do about it. Then, within one lifetime, scientists isolated the virus, built a vaccine, and drove measles out of entire continents.

The events of the 2020s show that this victory is not permanent. Measles comes back the moment we stop protecting against it. Samoa, Bangladesh, Canada, Mexico, and the United States have all learned this lesson in the past few years. The good news is that the solution has not changed. Two doses of a safe, inexpensive vaccine still work as well as they did in 1968.

Sources and Additional Reading

Disease, treatment, and clinical guidance

• Centers for Disease Control and Prevention. "Clinical Overview of Measles."
• Centers for Disease Control and Prevention. "Measles Symptoms and Complications."
• Centers for Disease Control and Prevention. "Measles (Rubeola)." CDC Yellow Book 2026.
• Biggerstaff M, Cauchemez S, Reed C, et al. "Estimates of the reproduction number for seasonal, pandemic, and zoonotic influenza: a systematic review." BMC Infect Dis. 2014;14:480.
• Centers for Disease Control and Prevention. "Chapter 13: Measles." Epidemiology and Prevention of Vaccine-Preventable Diseases (Pink Book).
• European Centre for Disease Prevention and Control. "Factsheet about measles."
• Mina MJ, Kula T, Leng Y, et al. "Measles virus infection diminishes preexisting antibodies that offer protection from other pathogens." Science. 2019;366(6465):599–606.
• World Health Organization. "Measles" fact sheet, updated 15 July 2026.

History

• Centers for Disease Control and Prevention. "History of Measles."
• Düx A, Lequime S, Patrono LV, et al. "Measles virus and rinderpest virus divergence dated to the sixth century BCE." Science. 2020;368(6497):1367–1370.
• Klass P, Ratner AJ. "'The Sombre Aspect of the Entire Landscape' — Epidemiology and the Faroe Islands." N Engl J Med. 2022;386(13):1202–1205.
• Morens DM, Taubenberger JK. "A forgotten epidemic that changed medicine: measles in the US Army, 1917–18." Lancet Infect Dis. 2015;15(7):852–861.
• Shanks GD. "Emerging infections: a perpetual challenge" (Fiji 1875 virgin-soil epidemic). Lancet Infect Dis. 2008.
• Penman BS, Gupta S, Shanks GD. "Rapid mortality transition of Pacific Islands in the 19th century." Epidemiol Infect. 2017;145(1):1–11.
• Shulman ST, Shulman DL, Sims RH. "The Tragic 1824 Journey of the Hawaiian King and Queen to London: History of Measles in Hawaii." Pediatr Infect Dis J. 2009;28(8):728–733.
• Tulchinsky TH. "Maurice Hilleman: Creator of Vaccines That Changed the World." Case Studies in Public Health. 2018:443–470.
• Zarshenas MM, et al. "Rhazes (865–925 AD)." J Neurol. 2018.

Vaccines

• Centers for Disease Control and Prevention. "Measles, Mumps, Rubella Vaccine (PRIORIX): Recommendations of the ACIP — United States, 2022." MMWR. 2022;71(46):1465–1470.
• Adigweme I, Yisa M, Ooko M, et al. "A measles and rubella vaccine microneedle patch in The Gambia: a phase 1/2 trial." Lancet. 2024;403(10439):1879–1892.
• Rosenthal SR, Clements CJ. "Two-dose measles vaccination schedules." Bull World Health Organ. 1993;71(3–4):421–428.
• Minnesota Department of Health. "Measles Vaccine Recommendations."

The Wakefield fraud

• Godlee F, Smith J, Marcovitch H. "Wakefield's article linking MMR vaccine and autism was fraudulent." BMJ. 2011;342:c7452.
• Dyer C. "Lancet retracts Wakefield's MMR paper." BMJ. 2010;340:c696.
• Immunize.org. "Brian Deer's BMJ investigation of MMR and Wakefield."
• Hviid A, Hansen JV, Frisch M, Melbye M. "Measles, Mumps, Rubella Vaccination and Autism: A Nationwide Cohort Study." Ann Intern Med. 2019;170(8):513–520.

Samoa 2019

• Thornton J. "In the aftermath: the legacy of measles in Samoa." Lancet. 2020;395(10236):1535–1536.
• BBC News. "Samoa measles outbreak: Why is it so deadly?" 5 December 2019.
• Al Jazeera. "Samoa shuts down in unprecedented battle against measles." 5 December 2019.
• RACGP newsGP. "Anti-vaccination advocates double down as measles deaths climb." 2019.

Global and regional epidemiology, 2024–2026

• World Health Organization. "Measles deaths down 88% since 2000, but cases surge." 28 November 2025.
• WHO Regional Office for Europe / UNICEF. "European Region reports highest number of measles cases in more than 25 years." 13 March 2025.
• Pan American Health Organization. "PAHO calls for regional action as the Americas lose measles elimination status." 10 November 2025.
• Pan American Health Organization. "Update on the review of measles elimination status." 2 March 2026.
• CNN. "A measles outbreak crossed into Mexico from Texas. A larger tragedy followed." 17 May 2026.
• Yuji K, Yuji W, Adachi E. "Importation-driven measles resurgence and the fragility of elimination, Japan, 2024–2026." Emerg Infect Dis. 2026;32(11).

United States, 2025–2026

• Centers for Disease Control and Prevention. "Measles Cases and Outbreaks." Updated 9 October 2026.
• Centers for Disease Control and Prevention. "Measles Update — United States, January 1–April 17, 2025." MMWR. 2025;74(14).
• Centers for Disease Control and Prevention. "Nowcasting measles cases, South Carolina, October 2025–March 2026." MMWR. 2026;75(33).
• Centers for Disease Control and Prevention. "Vaccination Coverage and Exemptions among Kindergartners." SchoolVaxView.
• Centers for Disease Control and Prevention. "Chapter 7: Measles." Manual for the Surveillance of Vaccine-Preventable Diseases.
• Texas Department of State Health Services. "Measles Outbreak – August 12, 2025."
• Utah Department of Health and Human Services. "2025–2026 Utah measles response."
• Pennsylvania Department of Health. "Statewide Update on Measles Outbreak as Cases Reach 1,078 in 41 Counties." 7 October 2026.
• Associated Press. "Coroner releases details of infants who died amid growing Pennsylvania measles outbreak." September 2026.
• Pennsylvania Department of Health. "Department of Health Confirms Fifth Measles-Associated Death." 30 September 2026.
• Office of Governor Kathy Hochul. "Governor Hochul Declares State Disaster Emergency in Response to Ongoing Measles Outbreak." 5 October 2026.
• American Hospital Association. "Pennsylvania measles outbreak grows as nation surpasses 4,000 confirmed cases." 9 October 2026.
• Reuters via U.S. News. "US Measles Cases Rise to 4,080, CDC Says." 9 October 2026.
• CNN. "Some measles patients in West Texas show signs of vitamin A toxicity, doctors say." 26 March 2025.

Bangladesh 2026

• World Health Organization. "Measles – Bangladesh." Disease Outbreak News, 23 April 2026.
• "The Impermanence of Public Health Gains — Lessons from the 2026 Measles Outbreak in Bangladesh." Emerg Infect Dis. 2026;32(11).
• Reuters. "Bangladesh fights world's worst measles outbreak as vaccination gaps fuel spread." 9 September 2026.

This page was last updated on October 12, 2026. .