Everything you needs to know about measles

 Measles outbreaks have become more common, and are especially dangerous for younger children and people who are pregnant or immunocompromised.

A dictionary page with the word measles highlighted in pink; the words contagious, viral disease, and in children.

Measles is a highly contagious respiratory illness caused by a virus. It can cause serious health complications, such as pneumonia, encephalitis (brain swelling), and even death. Measles is preventable with a vaccine.

Symptoms of Measles

Measles symptoms typically develop about 7-14 days after exposure to the virus. The initial symptoms of measles are similar to the common cold and may include:

- Fever (up to 104°F or 40°C)

- Runny or stuffy nose

- Cough

- Red, watery eyes (conjunctivitis)

- Feeling tired (listless)

A few days after the initial symptoms, these small, white spots with bluish-white centers may appear on the inner cheeks (Koplik spots).  

The measles rash is a red, raised, blotchy rash that usually starts on the face and hairline and spreads down the body over 3-5 days. The rash can be itchy and uncomfortable.  

Complications of Measles

Measles can lead to serious complications, especially in young children and adults. Some of the most common complications include:

- Pneumonia (an infection of the lungs)

- Ear infections

- Diarrhea and dehydration

- Encephalitis (brain swelling)

- Seizures

Here are some additional tips for preventing the spread of measles:

- Stay home if you are sick.

- Cover your cough and sneezes with a tissue or your elbow.

- Wash your hands frequently with soap and water.

- Disinfect surfaces that may be contaminated with the measles virus.

Here are four things that everyone needs to know about measles.

Measles is highly contagious

This is a point that can't be stressed enough. A full 90% of unvaccinated people exposed to the virus will catch it. And if you think that just staying away from sick people will do the trick, think again. Not only are people with measles infectious for four days before they break out with the rash, but the virus can live in the air for up to two hours after an infectious person coughs or sneezes. Just imagine: if an infectious person sneezes in an elevator, everyone riding that elevator for the next two hours could be exposed.

Measles can be dangerous

Most of the time, as with other childhood viruses, people weather it fine, but there can be complications. Children less than 5 years old and adults older than 20 are at highest risk of complications. Common and milder complications include diarrhea and ear infections (although the ear infections can lead to hearing loss), and one out of five will need to be hospitalized, but there also can be serious complications:

- One in 20 people with measles gets pneumonia. This is the most common cause of death from the illness.

- One in 1,000 gets encephalitis, an inflammation of the brain that can lead to seizures, deafness, or even brain damage.

- One to three in 1,000 children who get it will die.

Another possible complication can occur seven to 10 years after infection, more commonly when people get the infection as infants. It's called subacute sclerosing panencephalitis, or SSPE. While it is rare (four to 11 out of 100,000 infections), it is fatal.

Vaccination prevents measles

The measles vaccine, usually given as part of the MMR (measles-mumps-rubella) vaccine, can make all the difference. One dose is 93% effective in preventing illness; two doses gets that number up to 97%. 

Usually, the first dose is given between ages 12 to 15 months.

A second (booster) dose is commonly given between ages 4 to 6, although it can be given as early as a month after the first dose.

If an infant ages 6 to 12 months will be going to a place where measles regularly occurs, a dose of vaccine can be given as protection. This extra dose will not count as part of the required series of two vaccines.

The MMR is overall a very safe vaccine. Most side effects are mild, and it does not cause autism. Most children in the US are vaccinated, with 91% of 24-month-olds having at least one dose and about 93% of those entering kindergarten having two doses.

Herd immunity occurs when enough people are vaccinated that it's hard for the illness to spread. It helps protect those who can't get the vaccine, such as young infants or those with weak immune systems. To achieve this you need about 95% vaccination, so the 93% isn't perfect — and in some states and communities, that number is even lower. Most of the outbreaks we have seen over the years have started in areas where there are high numbers of unvaccinated children.

If you have questions about measles or the measles vaccine, talk to your doctor. The most important thing is that we keep every child, every family, and every community safe.