What is measles?

Measles is an infectious viral disease that occurs most often in the late winter and spring. It begins with a fever that lasts for a couple of days, followed by a cough, runny nose, and conjunctivitis (pink eye). A rash starts on the face and upper neck, spreads down the back and trunk, then extends to the arms and hands, as well as the legs and feet. After about five days, the rash fades the same order it appeared. 

Measles is highly contagious. Infected people are usually contagious from about 4 days before their rash starts to 4 days afterwards. The measles virus resides in the mucus in the nose and throat of infected people. When they sneeze or cough, droplets spray into the air and the droplets remain active and contagious on infected surfaces for up to two hours. 

Measles itself is unpleasant, but the complications are dangerous. Six to 20 percent of the people who get the disease will get an ear infection, diarrhea, or even pneumonia. One out of 1000 people with measles will develop inflammation of the brain, and about one out of 1000 will die. 

Before the measles vaccine became available, there were approximately 450,000 measles cases and an average of 450 measles-associated deaths were reported each year. Widespread use of measles vaccine has led to a greater than 99% reduction in measles cases in the U.S. compared with the pre-vaccine era. 

However, measles is common in other countries where it spreads rapidly and can be easily brought into the U.S. If vaccinations were stopped, measles would return to pre-vaccine levels in the U.S. and hundreds of people would die from measles-related illnesses. 

Is measles still a problem in the United States?

We still see measles among visitors to the U.S. and among U.S. travelers returning from other countries. The measles viruses these travelers bring into our country sometimes causes outbreaks. However, because most people in the U.S. have been vaccinated, these outbreaks are usually small.

Measles vaccination in the U.S. has decreased the number of cases to the lowest point ever reported. Widespread use of the measles vaccine has led to a greater than 99% reduction in measles compared with the pre-vaccine era when approximately 450,000 cases and 450 deaths were reported each year.

If the chance of the diseases is so low, why do I need the vaccine?

It is true that vaccination has enabled us to reduce measles and most other vaccine-preventable diseases to very low levels in the United States. However, measles is still very common — even epidemic — in other parts of the world. Visitors to our country and U.S. travelers returning from other countries can unknowingly bring this disease into the United States, and if we were not protected by vaccinations, it will quickly spread causing an epidemics here. The disease is very contagious.

We should be vaccinated protect ourselves and our children. Even if we think our chances of getting measles is small, the disease still exists and can still infect anyone who is not protected.

What kind of vaccine is given to prevent measles?

The MMR vaccine prevents measles and two other viral diseases — mumps and rubella. These three vaccines are safe given together. MMR is a attenuated (weakened) live virus vaccine. This means that after injection, the viruses grows, and causes a harmless infection in the vaccinated person with very few, if any symptoms. The person's immune system fights the infection caused by these weakened viruses and immunity develops which lasts throughout that person’s life.

How effective is MMR vaccine?

More than 95% of the people who receive a single dose of MMR will develop immunity to all three viruses. A second gives immunity to almost all of those who did not respond to the first dose. 

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hy is MMR vaccine given after the first birthday?

Most infants born in the United States will receive passive protection against measles, mumps, and rubella in the form of antibodies from their mothers. These antibodies can destroy the vaccine virus if they are present when the vaccine is administered and cause it to be ineffective. By 12 months of age, almost all infants have lost this passive protection.

What is the best age to give the second dose of MMR vaccine?

The second dose of MMR can be given anytime, as long as the child is at least 12 months old and it has been at least a month since the first dose. However, the second dose is usually administered before the child begins kindergarten or first grade (4-5 years of age) or before entry to middle school (11-12 years of age). The age at which the second dose is required is generally mandated by state school entry requirements.

As an adult, do I need the MMR vaccine?

You do not need the MMR vaccine if you

• had blood tests that show you are immune to measles, mumps, and rubella

• are a man born before 1957

• are a woman born before 1957 who is sure she is not having more children, has already had rubella vaccine, or has had a positive rubella test

• already had two doses of MMR or one dose of MMR plus a second dose of measles vaccine

• already had one dose of MMR and are not at high risk of measles exposure.

You should get the measles vaccine if you are not among the categories listed above, and

• are a college student, trade school student, or other student beyond high school
• work in a hospital or other medical facility
• travel internationally, or are a passenger on a cruise ship
• are a woman of childbearing age.

Do people who received MMR in the 1960s need to have their dose repeated?

Not necessarily. People who have documentation of receiving LIVE measles vaccine in the 1960s do not need to be revaccinated. People who were vaccinated prior to 1968 with either inactivated (killed) measles vaccine or measles vaccine of unknown type should be revaccinated with at least one dose of live attenuated measles vaccine. This recommendation is intended to protect those who may have received killed measles vaccine, which was available in 1963-1967 and was not effective.

Why are people born before 1957 exempt to receiving MMR vaccine?

People born in 1957 and before lived through several years of epidemic measles before the first measles vaccine was licensed. As a result, these people are very likely to have had the measles disease. Surveys suggest that 95% to 98% of those born before 1957 are immune to measles. Note: The "1957 rule" applies only to measles and mumps, and does NOT apply to rubella.

I am two months pregnant. Is it safe for me to have my 15-month-old vaccinated with the MMR vaccine?

Yes. Measles, mumps, and rubella vaccine viruses are not transmitted from the vaccinated person, so MMR does not pose a risk to a pregnant household member.

I am breast feeding my 2 month old baby. Is it safe for me to receive the MMR vaccine?

Yes. Breast feeding does not interfere with the response to MMR vaccine.

My 15-month-old child was exposed to chickenpox yesterday. Is it safe for him to receive the MMR vaccine today?

Yes. Disease exposure, including chickenpox, should not delay anyone from receiving the benefits of the MMR or any other vaccine.

What is the most common reaction following MMR vaccine?

Most people have no reaction. However, 5 percent to 10 percent of the people receiving the MMR vaccine experience a low grade fever and a mild rash.

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This page last modified on February 15, 2001