As the likelihood of outbreak grows in the United States, new research raises a red flag that 9 million children are at risk of measles because of gaps in vaccination.

A study presented this month at the annual conference of the Infectious Diseases Society of America found that one in eight children is susceptible to the illness. Children are susceptible to measles if they haven’t received the measles, mumps and rubella (MMR) vaccine – or if they’ve only received one of the two recommended doses.

Urgent care centers can help prevent outbreak by urging patients to get vaccinated, using the clinic as a convenient and affordable option for the service.

A headline-grabbing outbreak at Disneyland in December 2014 and several measles outbreaks in college student communities across the country in recent years highlight the issue, said Bonnie Peterson, RN, BSN, CAOHC, a senior consultant for Urgent Care Consultants. These events happened largely because many in the population have not had a second injection of MMR, Peterson said. The second shot boosts immunity levels from 94 percent to 99 percent.

“The world has become a smaller place with the ease of travel and foreign national students who have not been vaccinated attending out high schools and colleges,” Peterson said. “We must continue to vaccinate our young people to provide a herd immunity to protect our ‘at risk’ community, which cannot get the vaccine.”

Measles can lead to pneumonia, encephalitis, hospitalization and occasionally, death. Those who are not vaccinated or are undervaccinated are at risk because measles is very contagious through direct contact and droplets that can spread through the air. Measles is one of the most contagious of the vaccine-preventable diseases. It’s so infectious that 90 percent of people who are not immune will contract the virus if exposed, according to the U.S. Centers for Disease Control and Prevention.

The MMR vaccine is recommended for:

  • Children should get two MMR vaccines: one between 12-15 months and another between 4 and 6 years.
  • Adults who have never had an MMR vaccine
  • Adults who are not sure if they have had an MMR vaccine
  • Adults who have never had measles, mumps or rubella

The U.S. Centers for Disease Control and Prevention warns travellers of all ages to vaccinate against measles. All children should have had two doses of measles vaccine by age 6, which will be 97 percent effective in preventing infection. Children and adults travelling internationally should carry evidence of the vaccines.

Almost 90 percent of measles infections happened to adults, researchers reported in Clinical Infectious Diseases. There are still about 20 million cases worldwide every year. There have been recent outbreaks in Germany, France, Croatia and Bosnia.

Of the cases of measles reported in the U.S., most result from people getting infected in other countries and bringing it back here.

The research, done by Emory University and presented at this month’s Infectious Diseases Society conference, looked at data showing between 92 and 94 percent of children are immune to measles. That rate is just high enough to maintain “herd immunity” – which prevents the spread of the disease should a small outbreak occur. But below this threshold, measles outbreaks are possible and could lead to widespread illness. The researchers warn that the vulnerability could easily rise to one in seven children if measles vaccination rates continue to decline.

“Although we eliminated continuous measles transmission in the United States about 15 years ago thanks to the effectiveness of the MMR vaccine and robust vaccination rates, these study results show that we can’t get complacent,” said Robert Bednarczyk, PhD, lead author of the study and assistant professor in the Hubert Department of Global Health, Rollins School of Public Health at Emory University in Atlanta. “While we currently have overall immunity in the population that should prevent sustained measles transmission, if the virus is introduced, there is the potential for large outbreaks. This is because there are clusters of unvaccinated children in some communities, which could allow a large outbreak to occur with spread to similar communities.”