Measles: Managing the worst US outbreak in the last 25 years

With the rising number of confirmed measles cases in Texas and other parts of the country, the measles outbreak has served as a reminder of the importance of vaccines. The Centers for Disease Control and Prevention (CDC) reported that with 1,044 cases in 28 states, 2019 has been the worst year for measles in the U.S. in the last 25 years, a dramatic increase from 2018, when there were 372 reported cases of measles.

Worldwide, the World Health Organization reported a 300% increase in the number of measles cases in 2019 compared with the first three months of 2018. This is the highest number of cases since measles was effectively eliminated from the U.S. in 2000.

About the virus

Measles is a highly contagious respiratory pathogen spread by contact. The airborne virus lingers in the air for up to two hours after a contagious person has left an area. It causes high fever, runny nose, sore throat, cough, red eyes, conjunctivitis, and a rash. After a person is exposed to the virus, it typically takes 14 days for the rash to appear. Patients with measles can be contagious for four days before and after rash onset.

One out of every 1,000 people will have serious side effects from contracting the virus. Measles cause long-term problems with the lungs, ears, and brain. One of the most severe complications is encephalitis, swelling of the brain that can lead to death. Measles can also cause miscarriage or preterm birth in pregnant women. Another common long-term complication is sterility in males who contract the disease.

Susceptibility

Around 90% of people who are susceptible, often due to not being vaccinated, and who come into close contact with an infected person will contract measles. There is no treatment for the disease and medical care is focused on symptom relief.

Measles still appears in communities around the U.S., despite it being declared effectively eliminated in 2000. One reason is that there are people and communities who are unvaccinated against measles. This allows the extremely contagious disease to spread easily. Other than unvaccinated individuals, the population most at risk is babies, pregnant women, and people on chemotherapy or with weakened immune systems.

Another reason is that measles is prevalent in many other countries in the world. Unvaccinated travelers can get infected and then spread the virus to a location in the U.S.

The value of immunizations

Vaccination is the only defense against measles. The measles vaccine is 97% effective. People who receive two doses of the measles-mumps-rubella vaccine are considered immune.

“As a medical school, we are in the unique position of both caring for patients infected with highly contagious and risky pathogens and also educating about the importance of vaccines and the risk to individuals and populations of vaccine-preventable infections,” said Barbara Stoll, MD, dean of McGovern Medical School at UTHealth.

“As a specialist in pediatric infectious diseases, most of the patients I encounter are children admitted in the hospital,” said Susan Wootton, MD, associate professor of pediatrics at McGovern Medical School. “Last month was the first time in my career that measles was a serious consideration in the differential of children being admitted with fever and rash. That speaks to both the effectiveness of the vaccine over the past four decades as well as the growing anti-vaccine movement in our region.”

“Not vaccinating makes our population vulnerable to infectious diseases,” Wootton said. ”We must have 95% of our population vaccinated to have protection of a population, called herd immunity.”

Managing the virus in a clinical setting

If a patient with measles enters a clinic, health care providers are instructed to place a surgical mask on the patient, and an N95 respirator on themselves. The patient is then placed in an empty exam room with a closed door. Only staff who are immune to measles should care for the patient.

In Texas, suspicion of measles is required to be reported immediately. Do not wait for laboratory confirmation to report measles.

Contact:

• Harris County Public Health at 713-439-6000 or after hours at 713-755-5000
• Texas Department of State Health Services at 800-705-8868
• Infection Prevention at 713-500-5822 or 713-500-5849