Hillary Clinton on vaccinations: 'The science is clear'

Hillary Clinton weighed in on the national debate over children's vaccinations amid a measles outbreak that has sickened more than 100 people in the United States, posting a message on her Twitter feed late Monday.

"The science is clear," Clinton tweeted. "The earth is round, the sky is blue, and #vaccineswork. Let's protect all our kids. #GrandmothersKnowBest."

The former secretary of state and possible 2016 Democratic presidential candidate distanced herself from potential Republican hopefuls, including New Jersey Gov. Chris Christie and Kentucky Sen. Rand Paul.

Earlier Monday, Paul told CNBC that parents "should have some input" whether or not to vaccinate their children, saying it is "an issue of freedom."

"I have heard of many tragic cases of walking, talking, normal children who wound up with profound mental disorders after vaccines," he said.

Speaking in England, Christie said parents should have a "measure of choice" whether to vaccinate their children. The New Jersey governor's office quickly clarified his statements, saying "with a disease like measles there is no question kids should be vaccinated."

President Barack Obama waded into the debate Monday, too, saying parents have “every reason” to vaccinate their children against measles.

“You should get your kids vaccinated,” Obama told Savannah Guthrie during an interview broadcast on NBC’s “Today” show Monday. “It’s good for them.”

Obama echoed the message from American health professionals urging parents not to listen to anti-vaccination activists who have convinced some parents not to inoculate their children by claiming the vaccines can cause autism.

“I understand that there are families that in some cases are concerned about the effect of vaccinations,” Obama said. “The science is, you know, pretty indisputable. We’ve looked at this again and again. There is every reason to get vaccinated, but there aren’t reasons to not.”

Measles was once common in the United States but declined significantly because of higher vaccination rates. By 2000, the highly contagious disease had been declared officially eradicated from the United States.

“We should be able to get back to the point where measles effectively is not existing in this country,” the president said.

On Tuesday, House Speaker John Boehner was asked if Congress should have a role in the debate.

"I don't know that we need another law," Boehner said, "but I do believe that all children ought to be vaccinated."

According to the Centers for Disease Control and Prevention, the current measles outbreak, which began in California, has sickened more than 100 people in 14 states.

Of the 34 people for whom the California Department of Public Health had vaccination records, only 5 had received both doses of the measles vaccine, ABC News reported.

"This is not a problem with the measles vaccine not working," Dr. Anne Schuchat, director at the National Center for Immunization and Respiratory Diseases, said last week. "This is a problem of the measles vaccine not being used."

During the 2008 presidential campaign, both Obama and Clinton supported investing in research to determine if there was a link between vaccines and autism.

"We've seen just a skyrocketing autism rate. Some people are suspicious that it's connected to the vaccines," then-Sen. Obama said at an April 2008 rally. "The science right now is inconclusive, but we have to research it."

"We don't know what, if any, kind of link there is between vaccines and autism," Clinton responded to a 2008 questionnaire on autism research. "But we should find out."