More than 100 people in 14 states are now sick with the measles in an outbreak that has been traced back to an amusement park in California. Since the Centers for Disease Control and Prevention (CDC) deemed measles eliminated more than a decade ago, it’s no longer a virus the average American knows much about. But with measles now infecting persons in communities across the U.S., it’s important to know the basics. We sat down with Scott Lillibridge, a physician and public health expert at Texas A&M Health Science Center, to find out more about how this highly contagious respiratory disease spreads and how measles can be prevented.

Scott Lillibridge

Scott Lillibridge, M.D., professor at Texas A&M Health Science Center School of Public Health.

Q: What are the symptoms of measles?

A:  Patients suffering from measles usually present with a high fever, cough, runny nose and red, watery eyes that typically appear about seven to 21 days after infection. Several days after symptoms begin, a red rash breaks out on the face and spreads to the rest of the body.

Q: Is measles serious?

A: Measles is one of the most contagious infectious diseases that affect humans. Severe complications can occur, including pneumonia, encephalitis (swelling of the brain) and even death. Those with compromised immune systems, children under five and adults over 20 are more likely to develop severe complications. According to the CDC, approximately one in 1,000-2,000 patients with measles will have swelling of the brain and approximately six percent of all measles cases will get pneumonia.

Q: How do you prevent measles?

A: The most effective method of preventing measles and its complications is to be immunized. Because measles is extraordinarily contagious, doctor’s offices and emergency rooms ask that you isolate yourself and call ahead to discuss your illness with your health care provider if you believe that you might have measles. This will prevent others from contracting the disease from you in a public venue.

Q: How is measles spread?

A: Like many airborne infectious diseases, measles is spread primarily through coughing and sneezing, but can live on surfaces for up to two hours. There has been documented disease transmission in closed areas (such as physician exam rooms) for up to two hours after an infected individual had previously been examined in that space. It is important to note that individuals are contagious up to four days before and up to four days after the rash appears. Unfortunately, it is also possible to catch measles from someone before they have developed the characteristic rash.

Measles is highly contagious to persons who haven’t been vaccinated. In fact, if you are not immune, you have approximately a 90 percent chance of catching measles if you are in the same areas as an infected individual. However, close contact with an infected person is not required for measles transmission.

Q: How effective is the measles vaccine?

A: Measles can be prevented with the measles, mumps, and rubella, or MMR, vaccine. In the U.S., widespread use of the measles vaccine has led to a greater than 99 percent reduction in measles cases compared with the pre-vaccine era.  In short, the vaccine is highly effective. Before the measles vaccination program started in 1963, an estimated three to four million people got measles each year in the U.S. The number of measles cases reported in the U.S. has decreased dramatically, but measles cases are now on the rise again. The most recent outbreak associated with a California theme park is the most recent reminder that measles is still circulating, and vaccination against measles is still needed.

Q: Who should get the vaccine?

A: CDC recommends all children get two doses of MMR vaccine, starting with the first dose at 12 through 15 months of age, and the second dose at four through six years of age. Adults who do not have evidence of immunity, through vaccine records or laboratory tests to demonstrate immunity, are urged to get vaccinated.

Q: I thought measles was eradicated in the U.S. Why is it back?

A:  Measles transmission was eliminated in 2000 when the U.S. went 12 months without disease transmission, but unfortunately, vaccination rates have declined in the U.S. during the last decade in some communities. Fortunately, the more Americans that are vaccinated, the less likely it is that an outbreak will be sustained in the U.S. For example, when vaccination rates are high there are few susceptible persons (unvaccinated persons) for the virus to infect. As a consequence, sustained person-to-person measles transmission is difficult in this situation. We call this public health phenomenon “herd immunity.”  This confers an indirect benefit to those persons in the population who cannot be vaccinated (e.g., children under the age of 12 months, immunocompromised individuals, persons who have had a severe allergic reaction to the vaccine and pregnant persons).  In general, we are looking at a 95 percent rate of immunization to stop measles from transmission within a community.

It’s important to note that vaccinations protect not only the individual that has been immunized, but also indirectly protects others in the community as well. Vaccines remain one of the most effective tools we have to protect public health and prevent deaths around the world.

View an infographic on measles.

Scott Lillibridge, M.D., is professor at the Texas A&M Health Science Center School of Public Health and deputy principal investigator and chief scientist for the Texas A&M Center for Innovation in Advanced Development and Manufacturing. Dr. Lillibridge is a 30-year veteran in medical and public health preparedness who previously served as founding director of the Centers for Disease Control and Prevention Bioterrorism Preparedness and Response Program and also worked as Special Assistant to the Secretary for the U.S. Department of Health and Human Services. Dr. Lillibridge served as Medical Director of the U.S. Office of Foreign Disaster Assistance during the Ebola outbreak in the 1990s in Africa. He currently serves on the Institute of Medicine’s Health Threats Resilience Committee, offering expertise in refugee health and civil conflict, biodefense and bioterrorism, public health preparedness and response, and global health and development. 

— Holly Shive

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