What you need to know about measles

Although health officials declared measles eradicated in the U.S. nearly 20 years ago, the highly contagious disease is back in the news, as outbreaks spread on the West and East coasts.

While very young and unvaccinated children are at highest risk, some adults who only received one dose of vaccine as a child may have some susceptibility to the illness, according to the Centers for Disease Control and Prevention (CDC).

Dr. Jyotu Sandhu, a family medicine doctor with Sharp Rees-Stealy Medical Group, answers common questions about measles.

What does the measles look like?
The viral respiratory illness typically presents with a high fever, fatigue, cough, nasal congestion and conjunctivitis of the eyes, followed by a rash. The rash appears as flat red spots that start on the head and neck and spread down the body to the trunk, arms and legs. Patients are considered contagious for 4 days before and 4 days after the rash appears.

Who is at highest risk of contracting measles?
People at highest risk of developing measles include infants and children under age 5, adults over 20, pregnant women and people with compromised immune systems, such as cancer and HIV.

What are the health risks of measles?
Complications include ear and throat infection, bronchopneumonia, diarrhea, encephalitis (swelling of the brain) and death.

How does measles spread?
Measles is very contagious; up to 9 out of 10 susceptible persons with close contact with measles will develop the disease. It is transmitted by direct contact with viral particles from an infected person who breathes, coughs or sneezes. The virus can remain in a room for up to 2 hours after the infected person leaves the area.

How does someone know if they have an immunity to measles?
You have an immunity to measles if you meet one of the following:

• Written documentation of one or more doses of a measles-containing vaccine administered after 1968, on or after the first birthday for preschool-age children and for adults not at high risk.

• Written documentation of two doses of measles-containing vaccine after 1968 for school-age children and for adults at high risk, including college students, health care personnel and international travelers.

• Laboratory evidence of immunity by checking for antibodies in the blood.

• If you are born before 1957, as you most likely were exposed to measles as a child, and developed an immunity.

How does the vaccine work?
The body’s immune system makes protective virus-fighting antibodies against the harmless vaccine virus. Measles vaccine protects against wild-type measles. If a vaccinated person is exposed to someone with measles, the body remembers how to fight off the wild-type virus because the vaccine trained the immune system.

Why did the CDC announce that some adults born between 1963 and 1981 might not be fully immunized?
In the decades before 1963, when a vaccine became available, nearly all children got measles by the time they were 15 years old. By 1968, an improved vaccine was made available in the U.S. and has been used since, and is usually included in the MMR (measles, mumps and rubella) vaccine.

By 1981, the number of reported measles cases was 80% less than the previous year. Up to this point, children only received one dose of vaccine, so immunity status is uncertain. Adults who do not know the number of doses received can check their childhood vaccination record or talk with their doctor about whether their blood levels should be tested.

Why are two vaccine doses recommended?
In 1989, measles outbreaks among vaccinated school-age children prompted the Advisory Committee on Immunization Practices, the American Academy of Pediatrics and the American Academy of Family Physicians to recommend a second dose of MMR vaccine for all children.

By 2000, there were no active cases of measles in the U.S., until new outbreaks began in the past decade. The number of cases so far this year is the highest number since 2000.

Can children and adults reach full immunity with a measles booster shot?
Although one can’t achieve “full” immunity, receiving two doses of the vaccine provides 97% immunity to measles. Adults born between 1963 and 1981 who have questions or concerns about measles immunity should talk with their doctor. Immunity levels can be confirmed with a blood test.