The Infectious Return of Measles – A Previously ‘Eliminated Disease’ in the U.S.

by Anu Malani, MD, Medical Director, Infection Prevention and Control Services, St. Joseph Mercy Ann Arbor, Livingston and Chelsea

When I was a third-year medical student, measles was declared eliminated from the United States in 2000.

There has been a resurgence of measles, and there is significant concern that the disease can become widespread again. As of May 3, 2019, the U.S. has seen 764 cases of measles this year in 23 states, including 43 cases in Michigan. It’s only the beginning of May, and surveillance data shows that cases are well over 50% higher than numbers recorded last year. There will be many more cases of contracted measles in the upcoming months. There are several ongoing outbreaks across the U.S., including Michigan, New York, Washington, New Jersey, and California. The main reasons for the measles reemergence include more international travel – several countries have ongoing measles outbreaks – and low vaccination rates in several communities. Globally, the World Health Organization reports that measles cases in the first quarter of 2019 nearly quadrupled compared with what was reported at this time last year. 

Watch Dr. Malani and St. Joe’s Health Reporter Lila Lazarus discuss the measles outbreak on Facebook Live.

Measles has a better chance of transmission in places where vaccination rates have dropped to below 93 to 95 percent – the threshold required to protect the entire community. This concept is called “herd immunity” or community immunity, and an important reason why you and your family should receive recommended vaccines. When enough people in a community are vaccinated against measles (or another infectious disease), the virus can’t travel as easily from person to person — and the entire community is less likely to get the disease. That means even people who can’t get vaccinated will have some protection from becoming ill. And if a person does become sick, there’s less chance of an outbreak because it’s harder for the disease to spread. Eventually, the disease can become rare — and sometimes, it’s eliminated.

Measles is a viral infection that frequently causes a severe, flu-like illness characterized by fevers along with runny nose, cough, “pink eye”, and loss of appetite. A full body rash usually develops four days after the fever begins. Measles is highly contagious, and is spread through the air when a person with measles coughs or sneezes. Complications occur in 3 in 10 people who get measles, and young children are especially vulnerable.  About 25 percent of infected children are hospitalized. Ear infections and diarrhea are most common, but 1 in 20 will get pneumonia; 1 in 1,000 will have brain swelling that can cause deafness and intellectual disability; and 1 or 2 in 1,000 will die. Before the vaccine was available in 1963, nearly every child got measles by age 15. The disease sickened 3 to 4 million people and led to about 500 deaths and 48,000 hospitalizations every year.

Who is at the highest risk for measles?

Because most people in the United States have been vaccinated against measles, the risk to the general public is very low. Measles poses the highest risk to people who have not been vaccinated, to pregnant women, infants under 12 months of age and people with weakened immune systems.

How can measles be prevented?

Immunization is the best prevention for measles. The measles vaccine is very effective. According to the Centers for Disease Control and Prevention (CDC), one dose of the measles vaccine is about 93 percent effective, and two doses are about 97 percent effective at preventing measles. 

At what age can a person be vaccinated?

Measles can be prevented with the MMR vaccine. The vaccine protects against three diseases: measles, mumps, and rubella. The CDC recommends that children get two doses of MMR vaccine, starting with the first dose at 12 through 15 months of age. The second dose is usually given at 4 through 6 years of age, but it can be given as early as 4 weeks after the first dose. Teens and adults who are not up to date on their MMR should also be vaccinated. Adults in post-high school educational institutions, international travelers and working in healthcare require 2 doses while other adults require 1 dose. Those persons born before 1957 are presumptively considered immune. 

How can we to protect infants who are too young for vaccines?

The best way to protect those who cannot be vaccinated for measles (infants < 6 months, pregnant women, individuals with weakened immune systems) is to ensure their family members and close contacts are up-to-date on their MMR vaccination. It is also important to avoid contact with those that are ill.

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