A report based on the National Immunization Survey has revealed that about 9 million children in the United States remain unvaccinated against measles – and they not only risk getting infected but also raise the risk of infecting others. Also, the travelers that have not been vaccinated run the danger of bringing measles virus home to affect others.

Infectious disease experts met twice earlier this week and published two reports which examine the extents and gaps left open by measles vaccinations, and as well as the possibility of an outbreak occurring – similar to the one that took place in Disneyland earlier this year.

“If the virus is introduced, there is the potential for significant outbreaks,” said Robert Bednarczyk of Emory University, who led the work on the study. “This is because there are clusters of unvaccinated children in some communities, which could allow a significant outbreak to occur with spread to similar communities.”

Statistics from the National Immunization Survey was used by Bednarczyk and his team, and they found that 12.5% or 8.7 million UK kids are unvaccinated or fully vaccinated against measles; and a quarter of children aged three and under are unvaccinated.

Children are supposed to get two doses of the combined measles, mumps, and rubella (MMR) vaccine.

Fear of the side-effects of measles vaccines has kept many parents from vaccinating their children or delaying it. But Bednarczyk assured that vaccines are safe and highly recommended; otherwise children and vulnerable people could be prone to acute illnesses.

The Centers for Disease Control and Prevention reports that there have been 189 cases of measles in the US this year, including one death — a woman in Washington state. And all around the world, about 20 million people are not vaccinated against the disease, and over 145,000 children die every year from measles.

Dr. Emily Hyle of Massachusetts General Hospital and colleagues ran an experiment to show if travelers are aware of the risks they are open to and if they are vaccinated against measles and other diseases.

The team found that 16% of travelers cannot prove they have been immunized against measles, and it does not seem that doctors impress the need for them. Dr. Hyle noted that measles is one of the most contagious diseases in the world, and any slight exposure can lead to infection, even though children as most vulnerable to it.