According to a government study released on Thursday, children who remain unvaccinated for preventable diseases can become a public health threat. Only 1.7% of US parents of kindergartners sought exemptions in 2014 from laws, showed study.

Researchers during the study found that rates of parents seeking exemption varied across the nation. One of the states reported over 6% of parents seeking exemptions.

Dr. Anne Schuchat, Director of the CDC's National Center for Immunization and Respiratory Diseases, said, "Pockets of children who miss vaccinations exist in our communities and they leave these communities vulnerable to outbreaks of vaccine-preventable diseases".

It was noted that lawmakers in at least 10 states, including California, are taking initiatives to tighten school vaccination exemption rules after a measles outbreak at Disneyland in Anaheim sickened more than 100 people earlier this year.

As per official rules, all states require a schedule of vaccines that a child, before being enrolled in school, must have completed. Also, every state has to allow exemptions from vaccines for medical reasons, and all but Mississippi and West Virginia allow exemptions for religious reasons.

Schuchat said in a statement that as US measles vaccination rates are high, at 94% among kindergartenage children, the Disney outbreak was not a big problem in US than it was in Canada.

She said US has been lucky enough that it didn't had large outbreaks in schools. Seeing the data from Canada where in one province there were more than 100 measles cases from the Disney exposure. A majority of these cases were unvaccinated, she added.