Measles Vaccine Overview

Measles is a highly contagious viral infection. It is caused by the measles virus.

The virus is spread, typically in winter and spring, by direct contact with nasal or throat secretions of an infected person. Less commonly, it can be spread by droplets in the air. Measles is contagious:

• 1-2 days before the onset of symptoms
• 3-5 days before the rash
• 4 days after the appearance of the rash

Symptoms include:

• Fever (often high)
• Runny nose
• Red eyes
• Cough
• A distinctive rash

Symptoms usually begin within 8-12 days following exposure. The rash lasts about 4-6 days. Full recovery can take 7-10 days. In severe cases (or in people with immune disorders), serious brain infection or pneumonia can happen when recovering from measles. Permanent brain damage and death are very rare in the developed world.

Measles was once a common childhood illness. Now, there are far fewer cases of measles in the US. This is due to the measles vaccine.

Despite its success, there continue to be periodic measles outbreaks in the US. Although you are very unlikely to contract measles if properly immunized as a child, unvaccinated or inadequately vaccinated individuals are at increased risk of measles if they:

• Live in crowded and/or unsanitary conditions
• Travel to less developed countries where measles is common
• Have a compromised immune system (eg, HIV ), even if previously vaccinated
• Born after 1956 and never diagnosed with measles
• Have only received an inactivated or killed vaccine prior to 1968 (Today's live vaccines are much more effective.)

Because measles is caused by a virus, it cannot be treated with antibiotics. Efforts are focused on relieving the symptoms, such as:

• Gargling with warm salt water
• Cool mist humidification
• Lukewarm sponge baths
• Plenty of fluids and fever-reducing medicines (that do not contain aspirin)— Note: Aspirin should never be used in children and teens who have a current or recent viral infection.
• Vitamin A —This may be helpful for people who are deficient in vitamin A.

The measles vaccine consists of live measles viruses made in chicken embryo cells. The viruses found in the vaccine have been made harmless during the manufacturing process.

Although it is available as a single vaccine, it is normally given in combination with:

• Mumps and rubella vaccines (MMR)
• Mumps, rubella, and varicella (chicken pox) vaccine (MMRV)

The vaccine is given under the skin.

All children (with few exceptions) should receive the measles vaccine two times:

• 12-15 months
• 4-6 years (school entry)

The second dose can be given earlier, but the two doses must be separated by at least four weeks.

Infants aged 6-11 months can receive their first dose if they are exposed to a measles epidemic or will be travelling abroad. However, they should still receive the other two doses as normally scheduled for a total of three doses.

For catch-up vaccination, for those aged 18 years and who have not been vaccinated, two doses of MMR are given, separated by four weeks or longer.

Adults, aged 19-49 years, who have not been previously vaccinated, get one dose. Those who work in healthcare or a school setting, and those at high risk of exposure to measles, should get two doses. For adults 50 years and older who have not been vaccinated, one dose is given to those considered at high risk. *

In general, all older teens and adults should be vaccinated unless they meet one of the following criteria for measles immunity:

• Documentation of two live attenuated measles vaccines after their first birthday and spaced at least four weeks apart
• Documentation of doctor-diagnosed measles
• Blood test indicated immunity to measles
• Born before 1957

The majority of people who get the vaccine do not have any side effects. The most common side effects are a fever (103ºF or higher) and a rash. Redness and swelling at the injection site may occur. Rare complications include:

• Anaphylaxis —severe, life-threatening allergic reaction
• Temporary thrombocytopenia (low platelet count)—1 in 25,000 to 1 in 2 million vaccinations
• Encephalitis or encephalopathy (inflammation or other abnormality of the brain)—1 in 1 million vaccinations
• Seizures—in children predisposed to febrile seizures (convulsion during high fevers)
• Autism - The relationship between the MMR vaccine and autism is debated.

Most children and teens should receive their vaccinations on schedule. However, for certain groups of people, the risks may outweigh the benefits:

• People with immune system disorders (eg, AIDS )—If you have HIV and are doing well, you should consider getting the vaccine. Measles can be fatal if you have HIV.
• Pregnant women—Avoid becoming pregnant for at least one month after getting the vaccine.
• Previous severe allergic reaction to the vaccine or its components
• Previous thrombocytopenia clearly related to the vaccine

If you have close contact with someone who is at risk for the measles, you should get the vaccine. This will help stop the virus from spreading.

In some cases, the vaccine should be delayed, such as:

• Children who are sick with a fever—The vaccine can be given if you have a minor illness.
• Recent immunoglobulin (eg, antibody) or corticosteroids therapy

If you have the measles, the main approach is to isolate you to stop the virus from spreading. For example, children with the measles should stay home until the virus is over.

For people who have been exposed to the virus and are not vaccinated, the immunoglobulin (IG) shot can be given. The shot contains antibodies against the virus. If it is within six days of exposure, the shot can protect you. IG is especially important for:

• Children aged less than one year old
• Pregnant women
• People who have an immune system disorder

IG is not for those who have received at least one vaccination after 12 months of age, unless they have an immune system disorder.

A case of the measles needs to be reported to public health authorities. If you think your child has the measles, call the doctor right away.

In the event of an outbreak, people who were potentially exposed within the past two weeks should be vaccinated.

WHERE CAN I GET MORE INFORMATION?

Children’s Health Topics: Immunizations/Vaccines
American Academy of Pediatrics
http://www.aap.org/healthtopics/immunizations.cfm

National Immunization Program
Centers for Disease Control and Prevention
http://www.cdc.gov/vaccines/

References:

*Updated Who Should Get Vaccinated and When section on 1/31/2008 according to the following study, as cited by DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed/what.php : Centers for Disease Control and Prevention. Recommended immunization schedules for persons aged 0-18 years—United States, 2008. MMWR. 2008;57;Q1-Q4. Centers for Disease Control and Prevention, MMWR website. Available at: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5701a8.htm . Updated January 10, 2008. Accessed January 28, 2008.