What you need to know about the measles outbreak in Michigan

Michigan health officials have reported 22 cases of measles in the Detroit metropolitan area since March 13, the largest outbreak of the disease in the state in 25 years.

The outbreak is due to an Israel visitor from Oakland County, according to health officials. Since then, 21 people in Oakland County and one in Wayne County have been infected.

Of the 22 patients, three had been vaccinated, said Lynn Sutfin, spokesperson for the Michigan Department of Health and Human Services.

About 1,400 people have been vaccinated in Oakland County since the beginning of the outbreak two weeks ago, said Sutfin.

Here's what people need to know about measles:

1. Measles is very contagious.

Measles is one of the most contagious diseases in the world. It's so contagious that a measles patient can cough or sneeze, leave the room, and others can be infected walking into the room an hour or two later.

"Measles is so contagious that if a person is infected, up to 90% of those close to that person who are not immunized will also be infected," says the Federal Centers for Disease Control website.

Before the introduction of measles vaccine in 1963, an estimated 3 to 4 million people were infected with measles each year in the United States. Every year, about 400 to 500 people have died from measles and 48,000 have been hospitalized at the time of pre-vaccination, says the CDC.

2. The acute phase of the disease lasts about five to six days.

Measles usually starts with a mild to moderate fever, often accompanied by a persistent cough, a runny nose, an eye inflammation and a sore throat. This stage lasts two to three days.

The next step is a rash consisting of small red dots and bumps, starting with the face and extending along the arms and trunk. The fever can reach 105.8 degrees. The rash gradually resorbs, disappearing first from fasting and finally from the thighs and feet.

3. Measles can lead to serious complications.

The CDC states that measles can be serious in all age groups, especially in adults and children under 5 years of age. Among the complications, according to the CDC website:

• Ear infections affect approximately one in 10 children with measles and can lead to permanent hearing loss.
• Up to one in 20 children with measles contract pneumonia, the leading cause of measles deaths in young children.
• About one in 1,000 children who get measles will develop encephalitis, or swelling of the brain, which can cause convulsions and leave the child deaf or mentally handicapped.
• For 1,000 children with measles, one or two will die.
• Measles can cause a pregnant woman to give birth prematurely or have a low birth weight baby.

4, People with measles can transmit the disease before they feel sick.

Symptoms of measles usually appear about seven to 14 days after infection, although this may last up to 21 days. The person is contagious for about eight days. It begins four days before the onset of rash and ends four days after it appears.

This is a problem in the Greater Detroit area, where public health officials have a long list of places where measles patients may have contaminated others.

5. The measles vaccine is effective between 97 and 93%.

The MMR vaccine – which covers measles, mumps and rubella – is effective at about 97% for those who received two doses and 93% for those who received one.

Even if a vaccinated person gets measles, experts say that these people will probably have a less serious illness and less likely to transmit the disease to others.

Although the vaccine is very effective, measles is dangerous for babies too young to be vaccinated, as well as for people who can not be vaccinated because of allergies or a compromised autoimmune system.

6. If you have been exposed, the vaccine will work if it is administered within 72 hours.

If you have been exposed to measles and you are not vaccinated, you can probably prevent the disease by getting vaccinated within 72 hours of exposure, Sutfin said. In addition, gamma globulin injections are available for high-risk individuals who have been exposed and are not immune to the disease.

7. If you think you have measles, call before going to your doctor's office or emergency room.

Because measles is so contagious, do not go to the doctor or hospital without calling first.

"Of course, if you have measles, the first thing to do is to see a doctor," said Sutfin. "But obviously, on entering a doctor's office, you could expose a lot of other people. So we really insist on the importance of calling ahead and making arrangements. "