Measles Infection
What is Measles Infection?
Measles is a highly contagious viral infection that spreads through respiratory droplets when an infected person coughs or sneezes. The measles virus can live in the air and on surfaces for up to two hours. This makes it one of the most infectious diseases known to medicine.
Before the measles vaccine became available in 1963, nearly all children in the United States got measles by age 15. Today, vaccination has dramatically reduced cases in the United States. However, outbreaks still occur when unvaccinated people are exposed to the virus, often during travel to countries where measles remains common.
Your immune system creates antibodies to fight the measles virus after infection or vaccination. These antibodies, called Measles Ab IgG, remain in your blood for years and provide long-term protection. Blood tests can measure these antibodies to confirm past infection or immunity from vaccination.
Symptoms
- High fever, often reaching 104°F or higher
- Red, blotchy rash that starts on the face and spreads downward
- Dry cough that can be severe
- Runny nose and congestion
- Red, watery eyes and sensitivity to light
- Tiny white spots inside the mouth, called Koplik spots
- Sore throat and general body aches
- Extreme tiredness and weakness
Symptoms typically appear 10 to 14 days after exposure to the virus. The characteristic rash usually develops 3 to 5 days after symptoms begin. People are contagious from 4 days before the rash appears until 4 days after it develops.
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Causes and risk factors
Measles is caused by the measles virus, a member of the paramyxovirus family. The virus spreads when an infected person releases respiratory droplets into the air. You can catch measles by breathing contaminated air or touching infected surfaces and then touching your face. Up to 90% of unvaccinated people who are exposed to the virus will become infected.
Risk factors include lack of vaccination, vitamin A deficiency, travel to areas with ongoing outbreaks, and weakened immune systems. Young children under 5 and adults over 20 face higher risk of serious complications. Pregnant women who are not immune to measles also face significant risks, including preterm birth and low birth weight babies.
How it's diagnosed
Doctors typically diagnose measles based on the characteristic rash and other symptoms like fever and cough. Blood tests can confirm the diagnosis by detecting measles antibodies. The Measles Ab IgG test shows whether your immune system has responded to the virus or previous vaccination. A separate IgM antibody test can detect recent infection.
Your doctor may also take throat or nasal swabs to detect viral genetic material. These tests are especially important during outbreaks to confirm cases and track the spread of infection. Talk to a healthcare provider if you suspect measles exposure or want to confirm your immunity status before travel.
Treatment options
- Rest at home and avoid contact with others to prevent spread
- Drink plenty of fluids to prevent dehydration from fever
- Use a cool-mist humidifier to ease cough and sore throat
- Take fever reducers like acetaminophen or ibuprofen as directed
- Get vitamin A supplementation, especially for children, as recommended by a doctor
- Seek immediate medical care for high fever, difficulty breathing, or severe headache
- Post-exposure vaccination within 72 hours may prevent illness in unvaccinated people
- Immune globulin injections can help vulnerable people exposed to measles
Frequently asked questions
Measles typically lasts 7 to 10 days from the first symptoms to recovery. The fever usually breaks 2 to 3 days after the rash appears. Most people recover fully without lasting effects, though fatigue may persist for several weeks.
Yes, but it's rare. The MMR vaccine is about 97% effective after two doses. People who get measles despite vaccination usually experience milder symptoms. Breakthrough infections account for less than 3% of vaccinated individuals exposed to the virus.
About 1 in 5 unvaccinated people with measles need hospital care. Complications include pneumonia, brain inflammation called encephalitis, severe diarrhea and dehydration, and ear infections that can cause permanent hearing loss. Children under 5 face the highest risk of serious complications.
A blood test for Measles Ab IgG antibodies can show if you're immune. You're likely immune if you received two doses of MMR vaccine, had measles confirmed by a doctor, or were born before 1957 when most people were naturally exposed. Your doctor can order testing if you're unsure about your immunity status.
Call a doctor immediately if you develop measles symptoms after exposure to the virus. Seek emergency care for difficulty breathing, chest pain, severe headache, confusion, or seizures. Let the medical office know you suspect measles before arriving so they can take precautions to protect others.
The measles rash is red and blotchy, starting on the face and spreading downward over 3 to 4 days. Unlike some viral rashes, measles includes high fever, cough, and white spots inside the mouth. The rash typically appears 3 to 5 days after initial symptoms begin.
Yes, adults who were never vaccinated or infected can get measles. Adults often experience more severe symptoms than children. Complications like pneumonia and hospitalization are more common in adults over 20, making vaccination especially important for this age group.
No specific antiviral medication cures measles. Treatment focuses on managing symptoms and preventing complications. The body's immune system clears the infection naturally over 7 to 10 days. Prevention through vaccination remains the most effective approach.
Stay home and avoid contact with others from when symptoms start until 4 days after the rash appears. Use tissues when coughing or sneezing and wash hands frequently. Keep infected children out of school or daycare during this contagious period to protect unvaccinated individuals.
All children should receive two doses of MMR vaccine, the first at 12 to 15 months and the second at 4 to 6 years. Adults born after 1957 without proof of immunity should get at least one dose. Healthcare workers, international travelers, and college students may need two doses regardless of birth year.