Anti-vaxxers just were handed their biggest platform ever

Near the end of Wednesday night's second Republican presidential debate, CNN moderator Jake Tapper started a discussion among candidates over their views on vaccines.

Tapper asked candidate Ben Carson, a retired neurosurgeon, if he would say anything to the front-running Donald Trump, who has repeatedly linked vaccines to autism.

Carson skirted the issue.

"Vaccines are very important - certain ones, the ones that would prevent death or crippling," Carson said.

But he added, "There are a multitude of vaccines that probably don't fit in that category, and there should be some discretion in those cases."

Study after study has found that vaccines are safe and do not cause autism. And CNN earned criticism from some observers, who said that by bringing it up in the debate, CNN turned vaccines into a partisan issue, rather than a practice solidly backed by science.

"CNN now giving Trump a platform to spread misinformation about vaccines - can have real human costs. Ugh ugh ugh," wrote Brendan Nyhan, a political science professor at Dartmouth College.

Indeed, Trump responded by perpetuating what doctors have long warned is misinformation about vaccines.

"Autism has become an epidemic," Trump said, going on to tell the story of an employee's two-year-old child who he claims was vaccinated, developed a high fever, and subsequently developed autism.

Trump went on to contradict himself, saying, "I am totally in favor of vaccines, but I want smaller doses over a longer period of time."

Carson agreed with Trump, saying, "We are probably giving way too many in too short a period of time."

Tapper then pivoted to Sen. Rand Paul (R-Kentucky), an ophthalmologist.

"I'm all for vaccines, but I'm also all for freedom," Paul said, suggesting ensuring public health should be a matter of personal choice. "Even if the science doesn't say bunching them up's a problem, I ought to have the right to spread my vaccines out, at the very least."

Why spacing out vaccines is a bad idea

The Centers for Disease Control and Prevention, The American Academy of Pediatrics and the American Academy of Family Physicians do not recommend spacing out vaccines.

"Administering all needed vaccines at the recommended ages, even if it means giving multiple doses during the same visit, is important because it increases the likelihood that children will be fully immunized as recommended," the CDC says. "Studies have shown that vaccines are as effective when administered simultaneously as they are individually and carry no greater risk for adverse side effects."

Dr. Paul Offit, Chief of the Division of Infectious Diseases and the Vaccine Education Center at the Children's Hospital of Philadelphia, has said the recommended vaccine schedule is well-tested, and that giving them on a different schedule may not be as safe or effective. In addition, delaying vaccinations places a child at greater risk of getting infected, Offit wrote in an article published in the journal Pediatrics in 2009.

Dr. James Cherry, a professor of pediatrics at UCLA's medical school, said in a statement that spaced-out vaccines are not as effective."The measles outbreak in California earlier this year demonstrated that when vaccine schedules were spaced out, some children got severe measles."

He added, "Altering the schedule can lead to infections with vaccine-preventable diseases early in life when they may be particularly severe."