Measles

Measles is a highly-contagious respiratory disease caused by a virus. It spreads through the air through coughing and sneezing. Measles starts with a fever, runny nose, cough, red eyes, and sore throat, and is followed by a rash that spreads all over the body.
 
Measles is so contagious that if one person has it, 9 out of 10 people around that person will also become infected if they’re not yet vaccinated. You can get measles just by being in a room where a person with measles has been, even up to two hours after that person has left.  And what is even more worrisome is that an infected person can spread measles to others even before the infected person develops symptoms—from four days before they develop the measles rash through four days afterwards.
 
The good news is that measles can be prevented with the MMR (measles, mumps, and rubella) vaccine. The MMR vaccine has an excellent safety record and is highly effective. It is one of the most effective vaccines we have in our country.

Measles: Clinical Features and Diagnosis

Additional Background

In 2000, the United States declared that measles was no longer endemic (constantly present) in the country. The U.S. was able to eliminate measles because it has a highly effective measles vaccine, a strong vaccination program that achieves high vaccine coverage in children and a strong public health system for detecting and responding to measles cases and outbreaks.

One dose of measles vaccine is about 93 percent effective at preventing measles if exposed to the virus and two doses are about 97 percent effective. Most people in the United States are protected against measles through vaccination, so measles cases in the U.S. are uncommon compared to the number of cases before a vaccine was available. Since 2000, the annual number of people reported to have measles ranged from a low of 37 people in 2004 to a high of 668 people in 2014.

Since measles is still common in many countries, this disease is brought into the U.S. by unvaccinated travelers (Americans or foreign visitors) who get measles while they are in other countries. They can spread measles to other people who are not protected against measles, which sometimes leads to outbreaks. This can occur in communities with unvaccinated people.

Measles is highly contagious, so anyone who is not protected against measles is at risk of getting the disease. People who are unvaccinated for any reason, including those who refuse vaccination, risk getting infected with measles and spreading it to others, including those who cannot get vaccinated because they are too young or have specific health conditions.

In 2008, 2011, 2013 and 2014, there were more reported measles cases compared with previous years. The U.S. Centers for Disease Control and Prevention (CDC) experts attribute this to:

• more measles cases than usual in some countries to which Americans often travel (such as England, France, Germany,
  India, the Philippines and Vietnam), and therefore more measles cases coming into the US, and/or

• more spreading of measles in U.S. communities with pockets of unvaccinated people.
  

Very few people—about three out of 100—who get two doses of measles vaccine will still get measles if exposed to the virus. Experts aren’t sure why; it could be that their immune systems didn’t respond as well as they should have to the vaccine. But the good news is, fully vaccinated people who get measles are much more likely to have a milder illness, and they are also less likely to spread the disease to other people, including people who can’t get vaccinated because they are too young or have weakened immune systems.

You are considered protected from measles if you have written documentation (records) showing at least one of the
following:

• You received two doses of measles-containing vaccine, and you are a(n)—
  
  • school-aged child (grades K-12)
  • adult who was not vaccinated as a child and will be in a setting that poses a high risk for measles transmission, including
    students at post-high school education institutions, healthcare personnel and international travelers.
• You received one dose of measles-containing vaccine, and you are a(n)—
  
  • preschool-aged child
  • adult who was not vaccinated as a child and will not be in a high-risk setting for measles transmission.
• A laboratory confirmed that you had measles at some point in your life.
• A laboratory confirmed that you are immune to measles.
• You were born before 1957.

For international travelers, you are protected from measles if you have written documentation (records) showing at least one of the following:

• You received one dose of measles-containing vaccine, and you are an infant aged 6–11 months.
• You received two doses of measles-containing vaccine, and you are a person 12 months or older
• A laboratory confirmed that you had measles at some point in your life.
• A laboratory confirmed that you are immune to measles.
• You were born before 1957.