It moves through the air, when people speak, cough, or sneeze. A person carrying the virus can infect up to nine out of every 10 unprotected people in the same room, making it highly transmissible.
Measles is a highly infectious, dangerous disease caused by a virus. This virus causes a number of symptoms, notably a skin rash.
While the worldwide death rate attributed to measles has fallen since the vaccine was developed, it still kills more than 200,000 people each year—mostly children.
While it was quite a common childhood disease in the past, measles can now almost always be prevented with a vaccine.
Small white spots inside the mouth typically appear next, while the skin rash develops afterwards. The rash begins on the face behind the ears, spreading to the rest of the body.
It typically starts with cold-like symptoms, including a high temperature, a runny or blocked nose, sneezing, a cough, and sore, red eyes.
Measles is contagious for around eight days in total—for four days before the rash appears, and for four days afterwards.
Rare but potentially fatal complications can occur after infection, including a demyelinating disease (causing damage to myelin in nerve tissue) called acute disseminated encephalomyelitis (ADEM). This can occur two weeks after infection.
Neurologic infection with measles is relatively rare, occurring in only one out of 1,000 cases. However, neurologic infection carries a much higher risk of permanent harm, including death.
Ear infections and diarrhea are common complications, while more severe complications include pneumonia and encephalitis (inflammation of the brain).
Children under the age of five and adults over the age of 20 are more likely to suffer complications from a measles infection.
A loss of immune memory occurs after measles infection, resulting in immunosuppression, which increases the risk of dying for up to three years after contracting measles.
Another rare but deadly complication of measles infection is subacute sclerosing panencephalitis (SSPE), which typically occurs seven to 10 years later.
ADEM is a brief but intense attack of inflammation in the brain, spinal cord, and occasionally the optic nerves, which damages the brain's myelin.
SSPE, also known as Dawson's disease, is a progressive neurological disorder of children and young adults. It's a slow and persistent viral infection that affects the central nervous system.
Some people might think measles is a simple rash and fever that subsides after a few days, but as you can see, it can cause serious health complications.
There's no way to tell in advance how severe the complications will be in a person who contracts measles. But one in every five people who contract it in the US will be hospitalized.
One to three out of every 1,000 people will die, even if they receive the best possible care. One out of 1,000 people who catch measles develop brain swelling, which could lead to damage.
Pregnant women and those with compromised immune systems, such as from leukemia or HIV infection, are at a higher risk of suffering complications from measles.
More than 99% of people who receive both doses of the MMR vaccine develop immunity to measles. As immunity from the vaccine is so effective, the disease is not as common as it once was.
If you catch measles while pregnant, it can harm your baby. Measles in pregnancy can lead to miscarriage, stillbirth, premature birth (before the 37th week of pregnancy), or the baby having a low birth weight.
In the '60s, measles was extremely common, with epidemic outbreaks taking place every two to three years. It's estimated that up to 2.6 million deaths from measles occurred each year worldwide.
In the 1960s in the US, there were between three and four million cases of measles every year, resulting in 400 to 500 deaths.
It's extremely uncommon for those who've received two doses of the vaccine to contract measles, but it's not impossible.
In the US, measles is generally imported from abroad and spread in unimmunized and under-immunized people.
A physical exam is the primary way measles is diagnosed, but blood samples, urine samples, or nose and throat secretions can also be tested.
There is no cure for measles. The virus must run its course, which takes between 10-14 days. Symptoms are managed with NSAIDs, rest, drinking lots of fluids, gargling salt water, and avoiding harsh lights.
If you think you or your child might have been in contact with someone who has measles, or if you or your child have measles and it doesn't appear to be getting any better, contact your healthcare provider.
Measles isn't the only disease that causes a rash and fever. Roseola, rubella, chickenpox, and scarlet fever have similar symptoms. If in doubt, get in touch with your healthcare provider.
Sources: (Cleveland Clinic) (Piedmont Healthcare) (CDC) (WHO) (UChicago Medicine)
See also: The deadliest pandemics in history
Back in 2000, measles was declared eradicated in the US. That all changed less than 20 years later, when a measles epidemic took hold in 2019. The number of cases reached a high not seen since 1992, the majority of which were attributed to unvaccinated children. A highly infectious disease, cases have been reported each year since 2019 and the world has been experiencing a major increase since 2023. More than a dozen US states have reported cases of the illness since the start of 2024, and experts attribute the outbreak to increased travel and lower vaccination rates in children since the COVID-19 pandemic.
It looks like measles cases are on the rise around the world. But how dangerous is it? And what should you do if you think you have symptoms?
Click through this gallery to discover how dangerous measles is.
How worried should you be about the measles outbreak?
CDC urges vaccinations as cases surge in the US and around the world
HEALTH Disease
Back in 2000, measles was declared eradicated in the US. That all changed less than 20 years later, when a measles epidemic took hold in 2019. The number of cases reached a high not seen since 1992, the majority of which were attributed to unvaccinated children. A highly infectious disease, cases have been reported each year since 2019 and the world has been experiencing a major increase since 2023. More than a dozen US states have reported cases of the illness since the start of 2024, and experts attribute the outbreak to increased travel and lower vaccination rates in children since the COVID-19 pandemic.
It looks like measles cases are on the rise around the world. But how dangerous is it? And what should you do if you think you have symptoms?
Click through this gallery to discover how dangerous measles is.