Measles: Symptoms, Transmission, Complications, Treatment and Prevention
Measles is a highly contagious viral infection that can affect both children and adults.
Although many people recover, measles should not be dismissed as simply a childhood rash. It can cause serious complications including pneumonia, severe diarrhoea, brain inflammation and, in some cases, death.
Measles is also one of the most contagious infectious diseases known.
The good news is that measles is largely preventable through vaccination.
According to the World Health Organization (WHO), vaccination prevented an estimated 59 million measles deaths worldwide between 2000 and 2024.
However, measles continues to circulate in many parts of the world, particularly where vaccination coverage is insufficient.
What Causes Measles?
Measles is caused by the measles virus, which belongs to the Morbillivirus group.
The virus initially infects the respiratory tract and then spreads throughout the body.
Humans are the natural host of measles. The disease spreads from person to person.
Is Measles the Same as German Measles?
No.
Measles and rubella, sometimes called German measles, are different viral infections.
They can both cause a rash, but they are caused by different viruses and have different complications.
This distinction is especially important during pregnancy because rubella can cause severe congenital abnormalities in a developing baby.
The MMR vaccine protects against:
- Measles,
- Mumps,
- and Rubella.
How Does Measles Spread?
Measles spreads very easily through the air.
An infected person can release the virus when they:
- cough,
- sneeze,
- breathe,
- or otherwise release respiratory particles.
Other people can become infected by breathing contaminated air.
The virus can also remain infectious in an airspace or on contaminated surfaces for up to about two hours after an infected person has left.
How Contagious Is Measles?
Extremely contagious.
WHO reports that approximately 90% of people who are not immune and come into close contact with someone who has measles may become infected.
That means a single case can spread rapidly through households, schools and communities where many people are unvaccinated or otherwise lack immunity.
When Is Someone With Measles Contagious?
A person with measles can spread the virus before the characteristic rash appears.
They are generally considered contagious from approximately:
4 days before the rash appears until 4 days after the rash appears.
This is important because someone may unknowingly spread measles before realizing that they have the disease.
How Long After Exposure Do Symptoms Begin?
Symptoms do not usually appear immediately.
According to current CDC guidance, the first symptoms commonly develop approximately 7–14 days after infection.
WHO describes initial symptoms as generally appearing around 10–14 days after exposure.
The timing can vary between individuals.
What Are the First Symptoms of Measles?
Measles commonly begins with symptoms resembling a severe respiratory infection.
Early symptoms can include:
- high fever,
- cough,
- runny nose,
- and red, watery eyes.
These symptoms usually appear before the characteristic rash.
What Are Koplik Spots?
Some people with measles develop tiny white spots inside the mouth known as Koplik spots.
They may appear approximately two to three days after the first symptoms begin.
Koplik spots can be an important clinical clue, but their absence does not necessarily exclude measles.
A healthcare professional should assess suspected cases.
What Does a Measles Rash Look Like?
The measles rash generally develops several days after the first symptoms.
It often begins as flat red spots around the face and hairline.
The rash then typically spreads downward to the:
- neck,
- trunk,
- arms,
- legs,
- and feet.
Small raised bumps may sometimes appear over the flat red spots, and individual spots can merge together.
Fever can remain high when the rash develops.
Does Every Rash Mean Measles?
No.
Many conditions can cause a rash, including:
- other viral infections,
- allergic reactions,
- medicine reactions,
- chickenpox,
- rubella,
- and numerous skin conditions.
A rash should therefore not be diagnosed as measles based on appearance alone.
The person's symptoms, vaccination history, exposure history and appropriate laboratory testing may all be relevant.
Who Can Get Measles?
Anyone who does not have adequate immunity can potentially develop measles.
Although measles is commonly associated with childhood, adults can get measles too.
Adults who are not immune can also develop serious complications.
Who Is at Greater Risk of Serious Complications?
Measles can be serious at any age, but complications are more likely in certain groups.
These include:
- babies and young children,
- adults,
- pregnant women,
- people with weakened immune systems,
- and people affected by undernutrition, particularly vitamin A deficiency.
The precise risk differs according to the person's age, immune status, nutritional status and access to medical care.
Is Vitamin A Deficiency a Cause of Measles?
No.
Vitamin A deficiency does not cause measles.
Measles is caused by infection with the measles virus.
However, vitamin A deficiency is associated with a greater risk of severe measles and complications, particularly among children in settings where deficiency and undernutrition are common.
This distinction is important.
What Complications Can Measles Cause?
Measles can cause complications ranging from relatively common problems to life-threatening illness.
Possible complications include:
- ear infections,
- diarrhoea,
- dehydration,
- pneumonia,
- encephalitis,
- vision problems or blindness in severe cases,
- and death.
Pneumonia is an especially important cause of measles-related deaths in young children.
Measles and Pneumonia
Measles can cause serious respiratory complications.
Pneumonia may develop because of the measles virus itself or because another infection occurs while the person's immune defences are weakened.
Difficulty breathing, severe chest symptoms or a rapidly worsening condition requires urgent medical assessment.
Measles and Encephalitis
Encephalitis means inflammation of the brain.
It is an uncommon but potentially severe complication of measles.
It can cause symptoms such as:
- seizures,
- confusion,
- loss of consciousness,
- and neurological injury.
Some people who develop measles encephalitis can experience permanent disability.
Can Measles Cause Meningitis?
Neurological complications can occur with measles, including encephalitis and, less commonly, other inflammation involving the central nervous system.
However, the old article's simple statement that measles leads to “meningitis, appendicitis and lung infections” was not an appropriate description of the major complications.
Current international health guidance emphasizes complications such as pneumonia, encephalitis, severe diarrhoea, dehydration, ear infections and, in severe cases, blindness or death.
Is Appendicitis a Typical Measles Complication?
No.
Appendicitis should not be presented to readers as one of the standard major complications of measles.
It has therefore been removed from this updated article.
Can Measles Affect the Immune System?
Yes.
Measles can have effects on immune function that extend beyond the immediate illness.
Research has shown that measles can weaken previously developed immune protection against other infections, sometimes described as immune amnesia.
WHO notes that measles infection can make it more difficult for someone to fight other diseases for months or even years after the original measles illness.
This is another reason measles prevention is important.
What Is SSPE?
A rare but devastating long-term complication of measles is subacute sclerosing panencephalitis (SSPE).
SSPE is a progressive neurological disease that can occur years after the original measles infection.
It causes progressive brain damage and is usually fatal.
Although rare, SSPE demonstrates why preventing the original measles infection is preferable to relying on immunity acquired by becoming ill.
Measles During Pregnancy
Measles during pregnancy can be dangerous.
Pregnant women who develop measles may have an increased risk of serious illness.
Measles during pregnancy can also be associated with problems such as:
- premature birth,
- and low birth weight.
Anyone who is pregnant and thinks they have been exposed to measles should seek medical advice promptly.
Because MMR is a live vaccine, it is generally not administered during pregnancy. Vaccination status is ideally addressed before pregnancy or after delivery according to appropriate medical guidance.
Is There a Specific Medicine That Cures Measles?
There is no routine antiviral medicine that directly cures uncomplicated measles.
Treatment generally focuses on supportive care while the immune system fights the infection.
This can include:
- adequate fluids,
- nutrition,
- management of fever and discomfort,
- and treatment of complications.
People with severe disease may require hospital care.
Antibiotics do not treat the measles virus itself, although they may be prescribed when a bacterial complication such as certain ear infections or pneumonia develops.
What About Vitamin A Treatment?
Vitamin A has an important role in the management of measles in children in certain circumstances.
WHO recommends vitamin A supplementation for children with measles according to appropriate clinical guidance because it can reduce the risk of some complications and deaths, particularly where deficiency is present.
However:
Do not give high-dose vitamin A to a child without appropriate medical guidance.
Excessive vitamin A can be harmful.
Vitamin A is not a substitute for vaccination.
What Is the Best Way to Prevent Measles?
The most effective way to prevent measles is vaccination.
WHO recommends that susceptible children receive two doses of a measles-containing vaccine through national immunization programmes.
Depending on the country, this may be given as:
- measles vaccine,
- measles-rubella (MR),
- measles-mumps-rubella (MMR),
- or measles-mumps-rubella-varicella (MMRV).
Vaccination schedules differ between countries.
Follow the routine immunization schedule where you live.
How Effective Is the MMR Vaccine?
The measles-containing vaccine is highly effective.
CDC data indicate that:
- one dose of MMR is about 93% effective at preventing measles,
- while two doses are about 97% effective.
No vaccine provides 100% protection to every individual, but high vaccination coverage dramatically reduces measles transmission and outbreaks.
Is the Measles Vaccine Safe?
Measles-containing vaccines have been used worldwide for decades.
Most vaccine reactions are mild and temporary.
Possible reactions can include:
- soreness at the injection site,
- mild fever,
- or a mild rash.
Serious vaccine reactions are rare.
The health risks associated with measles infection are substantially greater than the risk of serious reactions to the vaccine.
Does the MMR Vaccine Cause Autism?
No.
High-quality scientific research has found no causal relationship between MMR vaccination and autism.
The original claim suggesting such a link came from research that was subsequently discredited and retracted.
Vaccination remains the most effective way to prevent measles.
Can Vaccinated People Still Get Measles?
Rarely, yes.
No vaccine is completely effective in every individual.
However, two appropriately administered doses provide very strong protection.
When vaccinated people do develop measles, disease may sometimes be less severe.
Vaccination also reduces the number of susceptible people in the community, making outbreaks less likely.
Is Natural Measles Infection Better Than Vaccination?
No.
Recovering from measles generally produces strong immunity, but acquiring that immunity requires experiencing the actual disease and accepting its risks.
Those risks include:
- pneumonia,
- encephalitis,
- hospitalization,
- long-term neurological complications,
- and death.
Vaccination provides protection without requiring someone to first experience those risks.
What Should You Do If You Think You Have Measles?
If you or your child has symptoms that could be measles, particularly after a known exposure or during an outbreak:
Contact a healthcare professional before arriving at a clinic or waiting room whenever possible.
Explain that you suspect measles.
This allows the healthcare facility to make arrangements that reduce the chance of exposing other patients.
Avoid unnecessary close contact with other people while waiting for medical advice.
What If You Have Been Exposed but Have No Symptoms?
Contact a healthcare professional or local public-health service promptly.
Depending on factors such as:
- your vaccination history,
- age,
- immune status,
- pregnancy,
- and how recently the exposure occurred,
post-exposure measures may sometimes be recommended.
These can include a measles-containing vaccine for eligible people or immune globulin for certain high-risk individuals.
Timing matters, so seek advice promptly rather than waiting for symptoms.
Should Someone With Measles Go to School or Work?
No, not during the infectious period.
People with measles should follow isolation instructions from their healthcare or public-health authority.
As a general rule, a person with measles is considered infectious from approximately four days before until four days after the rash appears.
Specific instructions may differ for people with weakened immune systems or according to local public-health requirements.
Does Avoiding Shared Food Prevent Measles?
Not effectively by itself.
The old article advised readers not to share food and drinks with someone who has measles.
While normal hygiene is sensible, measles prevention cannot rely on avoiding shared food because the virus spreads very efficiently through the air.
Vaccination, appropriate isolation and rapid public-health response are far more important.
Does Good Nutrition Prevent Measles?
Good nutrition supports overall health and immune function, but a healthy diet does not make an unvaccinated susceptible person immune to measles.
The primary preventive measure is vaccination.
Nutrition becomes particularly important because undernourished children—including those deficient in vitamin A—can have a greater risk of severe disease.
Can Measles Be Eliminated?
Yes, measles can potentially be eliminated from countries and regions because:
- humans are the only natural reservoir,
- highly effective vaccines exist,
- and there is no chronic carrier state maintaining transmission indefinitely.
However, elimination requires very high vaccination coverage.
Gaps in vaccination allow outbreaks to return.
WHO reported that by the end of 2025, approximately 84% of children worldwide had received a first measles-containing vaccine dose and 77% had received two doses.
Those global levels remain below what is needed to reliably prevent outbreaks everywhere.
Why Measles Vaccination Protects Communities
Measles spreads so easily that communities require very high levels of immunity to interrupt transmission.
High vaccination coverage protects vaccinated individuals and also reduces the likelihood that the virus reaches people who cannot receive certain vaccines for medical reasons.
This is why measles vaccination is both an individual and public-health measure.
When Should You Seek Urgent Medical Care?
Seek urgent medical assessment if someone with suspected or confirmed measles develops:
- difficulty breathing,
- severe dehydration,
- extreme drowsiness or difficulty waking,
- confusion,
- seizures,
- severe weakness,
- bluish or unusually pale skin,
- or a rapidly worsening condition.
Babies, pregnant women and people with weakened immune systems may require particularly careful assessment.
Contact your local emergency medical service if the situation appears life-threatening.
Seven Important Facts About Measles
1. Measles is caused by a virus.
Antibiotics do not cure the virus itself.
2. Measles spreads through the air.
It is one of the world's most contagious infections.
3. You can spread measles before the rash appears.
The infectious period generally begins about four days before the rash.
4. Measles is not simply a harmless childhood rash.
Pneumonia, encephalitis and other serious complications can occur.
5. Adults can get measles too.
Anyone without adequate immunity can be infected.
6. Two vaccine doses provide strong protection.
7. Suspected measles should be reported before walking into a healthcare facility.
Calling ahead helps protect other patients from exposure.
The Bottom Line
Measles is an extremely contagious viral infection that can affect children and adults.
Typical symptoms include high fever, cough, runny nose, red watery eyes and a rash that usually begins on the face before spreading downward.
Tiny white Koplik spots may also appear inside the mouth.
Although many people recover, measles can cause serious complications including pneumonia, severe diarrhoea and dehydration, encephalitis, blindness and, in rare cases, long-term neurological disease or death.
The most effective protection is vaccination.
Two doses of a measles-containing vaccine provide strong protection and are recommended through national immunization programmes around the world.
If you think you or your child has measles, contact a healthcare professional promptly and call before attending a clinic or hospital whenever possible, so measures can be taken to avoid exposing other people.
Measles is preventable. Maintaining high vaccination coverage remains one of the most effective ways to protect individuals, families and communities.
Medical Disclaimer
This article provides general health information for an international audience and is not a substitute for diagnosis, vaccination advice or treatment from an appropriately qualified healthcare professional. Vaccination schedules and outbreak-control procedures differ between countries. If you think you or your child has been exposed to measles or has symptoms of measles, contact an appropriate healthcare professional or public-health service promptly. Seek urgent medical care for serious symptoms such as breathing difficulty, seizures, confusion, severe dehydration or rapidly worsening illness.
Sources and Further Reading
World Health Organization — Measles
https://www.who.int/health-topics/measles
World Health Organization — What You Need to Know About Measles
https://www.who.int/news-room/questions-and-answers/item/what-you-need-to-know-about-measles
World Health Organization — Immunization Coverage
https://www.who.int/news-room/fact-sheets/detail/immunization-coverage
World Health Organization — Measles Vaccines
https://www.who.int/teams/immunization-vaccines-and-biologicals/diseases/measles
Centers for Disease Control and Prevention — About Measles
https://www.cdc.gov/measles/about/
Centers for Disease Control and Prevention — Measles Symptoms and Complications
https://www.cdc.gov/measles/signs-symptoms/index.html
Centers for Disease Control and Prevention — How Measles Spreads
https://www.cdc.gov/measles/causes/index.html
