The thought of measles may bring to mind the red, blotchy rash that often accompanies this disorder. But the rash is just an outward sign of the more worrisome changes happening inside your body. Measles is primarily a respiratory infection caused by a highly contagious virus found all over the world.
Also called rubeola, measles can be serious and even fatal for small children. Approximately 30 million to 40 million cases of measles occur worldwide each year, resulting in close to 1 million deaths. Measles (rubeola) is not the same as rubella, a condition caused by a different virus that is less contagious and results in less severe symptoms.
The measles vaccine is a highly effective way to prevent the measles illness. Thanks to the vaccine, less than 50 cases of measles were reported in the United States in 2004. However, vaccination programs are incomplete in much of the world. Global health organizations are working hard to address this problem. The widespread nature of the disease is why vaccination programs are still necessary in countries where few cases of measles occur. The disease can spread easily with international travelers.
The cause of measles is a virus. The measles virus is so contagious that if one person has it, 90 percent of that person's close contacts who aren't immunized will become infected.
The virus lives in the mucus in the nose and throat of an infected child or adult. That child or adult is contagious from four days before the rash appears to four days after. When someone with measles coughs, sneezes or talks, infected droplets spray into the air, where other people can inhale them. The infected droplets may also land on a surface where they remain active and contagious for several hours. You can contract the virus by putting your fingers in your mouth or nose after touching the infected surface.
Once the virus gets inside your body, it typically grows in the cells that line the back of the throat and lungs. The infection then spreads throughout the body, including the respiratory system and the skin.
Risk Factor :
Measles is highly contagious. Any exposure to an infected person may cause the infection if you aren't immune to the disease. Measles is rare in the United States because most people are vaccinated against the infection at an early age.
If you've already had measles, your body has built up its immune system to fight the infection, and you can't get measles again. If you were born or living in the United States before 1957, you're probably immune to measles, even if you were never vaccinated. You lived through several years of measles epidemics and were likely infected naturally by the measles virus. Even if you didn't develop symptoms, you probably have acquired immunity.
Measles is more common in lesser developed countries, particularly where people suffer from vitamin A deficiency as part of malnutrition. This may be something to consider before traveling abroad.
When to seek medical advice :
Call your doctor if you think you or your child may have been exposed to measles, or if you or your child exhibits symptoms that make you suspect measles. Remember: Most childhood rashes won't actually be measles, but cases of measles still do occur in the United States.
Also be sure to review your child's immunization records with your doctor, especially before starting elementary school, before college and before international travel.
Measles symptoms and signs appear 10 to 12 days after exposure to the virus. They typically include :
- Dry cough
- Runny nose
- Inflamed eyes (conjunctivitis)
- Sensitivity to light
- Tiny red spots with bluish-white centers found inside the mouth on the inner lining of the cheek, called Koplik's spots
- A skin rash made up of large, flat blotches that often flow into one another
The course of the measles virus
Measles typically begins with a mild to moderate fever, accompanied by other signs and symptoms, such as a persistent cough, runny nose, inflamed eyes (conjunctivitis) and sore throat. Two or three days later, Koplik's spots — a characteristic sign of measles — appear. Then a fever spikes, often as high as 104 or 105 F. At the same time, a red blotchy rash appears, usually on the face, along the hairline and behind the ears. This slightly itchy rash rapidly spreads downward to the chest and back and, finally, to your thighs and feet. After about a week, the rash fades in the same sequence that it appeared.
Your doctor can usually diagnose measles based on the disease's characteristic rash as well as the small, bright red spots with bluish-white centers on the inside lining of the cheek, called Koplik's spots. Because measles is so uncommon in the United States today, your doctor may obtain a blood sample to confirm whether the rash is truly measles.
Measles usually lasts about 10 to 14 days. In some parts of the world, the disease is severe, even deadly. In Western countries, that's usually not the case. People with measles may become quite ill, but most people recover completely. However, complications may include :
- Ear infection. Measles causes an ear infection in nearly one out of every 10 children.
- Encephalitis. About one in 1,000 people with measles develops encephalitis, an inflammation of the brain caused by a viral infection, which may cause vomiting, convulsions and, rarely, coma. Encephalitis can closely follow measles, or it can occur years later during adolescence as a result of a slow virus infection. The late form, called Dawson's encephalitis, is rare.
- Pneumonia. As many as one in 15 with measles gets pneumonia, which can be life-threatening.
- Diarrhea or vomiting. These complications are more common in infants and small children.
- Bronchitis, laryngitis or croup. Measles may lead to inflammation of your voice box (larynx) or inflammation of the inner walls that line the main air passageways of your lungs (bronchial tubes).
- Pregnancy problems. Pregnant women need to take special care to avoid measles, because the disease can cause miscarriage, premature labor or babies with low birth weights.
- Low platelet count (thrombocytopenia). Measles may lead to a decrease in platelets — the type of blood cells that are essential for blood clotting.
No treatment can get rid of an established measles infection. However, nonimmunized infants may be given the measles vaccination within 72 hours of exposure to the measles virus, to provide protection against the disease. Pregnant women, infants and people with weakened immune systems who are exposed to the virus may receive an injection of proteins (antibodies) that can fight off infection, called immune serum globulin. When given within six days of exposure to the virus, these antibodies can prevent measles or make symptoms less severe.
You or your child may also take over-the-counter medications such as acetaminophen (Tylenol, others) or nonsteroidal anti-inflammatory drugs (NSAIDs) to help relieve the fever that accompanies measles. Don't give aspirin to children because of the risk of Reye's syndrome — a rare but potentially fatal disease.
If you develop a bacterial infection while you have measles, such as pneumonia or an ear infection, your doctor may prescribe an antibiotic. Young children who are hospitalized with severe measles might also benefit from prescription doses of vitamin A.
Isolation is another element of treatment. Because measles is highly contagious from about four days before to four days after the rash breaks out, people with measles shouldn't return to activities in which they interact with other people during this period. It may also be necessary to keep nonimmunized people — siblings, for example — out of the infected person's house. Talk with your doctor about keeping someone with measles isolated.
The measles vaccine is extremely effective. Before this vaccine, there were approximately 450,000 measles cases and 450 measles-associated deaths in the United States each year. Widespread use of the vaccine has reduced the number of measles cases in the United States by more than 99 percent.
The measles vaccine is usually given as a combined measles-mumps-rubella (MMR) inoculation, which contains the safest and most effective form of each vaccine. It's made by taking the measles virus from the throat of an infected person and adapting it to grow in chick embryo cells in a lab. When this modified measles virus is given to a child as part of the MMR vaccine, the virus grows and causes a harmless infection before the immune system gets rid of it. This harmless infection causes 95 percent of children to develop lifetime immunity to the virus. But a second dose of the vaccine is recommended to protect the 5 percent who didn't develop immunity after the first dose and to boost immunity in the 95 percent who did.
Doctors recommend that children receive the MMR vaccine between 12 and 15 months of age, and again between 4 and 6 years of age — before entering school. Usually babies are protected from measles for about six months after birth because of the immunity passed on from their mothers. If a child requires protection from measles before 12 months of age — for example, for certain foreign travel or in case of an outbreak — the vaccine can be given as early as 6 months of age. But it needs to be repeated after 12 months of age.
Do you need the MMR vaccine?
You don't need to be vaccinated if you :
- Had two doses of the MMR vaccine after 12 months of age or one dose of the MMR vaccine plus a second dose of measles vaccine
- Have blood tests that prove you're immune to measles, mumps and rubella
- Are a man who was born before 1957
- Are a woman who was born before 1957 and you don't plan to have any more children
You should be vaccinated if you don't fit the criteria listed above and you :
- Are a nonpregnant woman of childbearing age
- Attend college, trade school or postsecondary school
- Work in a hospital, medical facility, child care center or school
- Plan to travel overseas or take a cruise
The vaccine is not recommended for :
- Pregnant women or women who plan to get pregnant within the next four weeks
- People who have had a life-threatening allergic reaction to gelatin or the antibiotic neomycin
If you have cancer, a blood disorder or another disease that affects your immune system, talk to your doctor before getting an MMR vaccine.
Side effects of the vaccine
Most people experience no side effects from the vaccine. About 10 percent of people develop a fever between five and 12 days after the vaccination, and about 5 percent of people develop a mild rash. Fewer than one out of a million doses causes a serious allergic reaction.
It was once commonly believed that people who were allergic to eggs couldn't receive vaccines grown in chick embryos, such as the measles vaccine. But this isn't true. People with allergies to eggs can safely receive the measles vaccine as well as the combined MMR vaccine.
In recent years, some news reports have raised concerns about a connection between the MMR vaccine and autism. However, extensive reports from the American Academy of Pediatrics, the Institute of Medicine and the Centers for Disease Control and Prevention conclude that there's no scientifically proven link between the MMR vaccine and autism. In addition, there's no scientific benefit to separating the vaccines. These organizations note that autism is often identified in toddlers between the ages of 18 months and 30 months, which happens to be about the time children are given their first MMR vaccine. But this coincidence in timing shouldn't be mistaken for a cause-and-effect relationship.