REUTERS/Scott Audette Rep. Michele Bachmann (R-MN) participates in the CNN/Tea Party Republican presidential candidates debate in Tampa, Florida, September 12, 2011.

Monday night’s Republican primary debate saw candidate Michele Bachmann on the attack — especially against Texas Gov. Rick Perry. Bachmann slammed Perry for signing an executive order in 2007 requiring all sixth-grade girls to get vaccinated against HPV, the virus that is the leading cause of cervical cancer.

Most media reports following the debate focused on Bachmann’s key criticism of Perry: his engaging in “capital cronyism.” She accused Perry of acting under the influence of campaign donations from HPV vaccine manufacturer, Merck, which stood to gain millions from mandatory vaccination.

She further noted that the executive order — a tactic that the governor admits was a mistake and that was subsequently overturned — would have prevented some families from being able to choose whether or not to get the vaccine. (The federal government recommends the HPV vaccine for all 11- and 12-year-old girls.)

But perhaps more disturbing are comments Bachmann made Tuesday morning about the safety of the HPV vaccine itself — and what they revealed about her utter misunderstanding of the science.

LIST: Gov. Rick Perry’s Weird Science

Talking with Matt Lauer on the Today show, Bachmann said that the vaccine was “a very dangerous drug.” She continued:

I had a mother come up to me last night here in Tampa, Fla., after the debate. She told me that her little daughter took that vaccine, that injection. And she suffered from mental retardation thereafter. The mother was crying when she came up to me last night. I didn’t know who she was before the debate. This is the very real concern and people have to draw their own conclusions.

In fact, “mental retardation” is not a “very real concern” when it comes to vaccination. Rather, Bachmann is resurrecting the alleged connection between vaccines and mental disability — namely autism — which has been repeatedly debunked. Last year, the fraudulent research that first triggered parents’ widespread and persistent fear of vaccination was retracted by the medical journal that published it, and its author, Andrew Wakefield, was stripped of his medical license.

In August, a sweeping report by the Institute of Medicine (IOM) analyzed all the available data on the adverse events associated with eight childhood vaccines and found few risks. Notably, it also confirmed that there was no connection between the measles, mumps and rubella vaccine (MMR) — the vaccine that so many parents still fear — and autism risk.

The IOM report also included data on the HPV vaccine, finding some evidence to indicate that the side effect of fainting was a concern. But it did not find sufficient evidence to support any side effects involving development, such as mental retardation.

Further, according to data from the Centers for Disease Control and Prevention (CDC), which were published in the Journal of the American Medical Association (JAMA), mental retardation is not a known side effect of the vaccine. Reported side effects include local injection site reactions, fainting, dizziness, nausea and headaches, as well as hypersensitivity reactions like rashes, hives and itching — all noted on the drug’s labeling.

The vaccine’s label also makes note of more serious but rare adverse events like Guillain-Barré syndrome, pregnancy and death, but analysis of the data show that these events were not connected to the vaccine. Rather they coincidentally occurred in people who also got the vaccine. (Indeed, imagine if a vaccine could make you pregnant?)

MORE: Vaccine Safety: New Report Finds Few Adverse Events Linked to Immunizations

It’s that element of coincidence that continually seems to confuse people like Bachmann, who don’t have a firm grasp of the science. Earlier this year, I spoke with vaccinologist Paul Offit, author of Deadly Choices: How the Anti-Vaccine Movement Threatens Us All, who explained the muddle.

Many of the side effects that parents associate with mandatory childhood vaccinations — especially problems that affect mental health — are actually just coincidental medical events, Offit said. Autism, some symptoms of brain damage and other traits often emerge between ages 1 and 4, the same time period that many vaccinations, including MMR, are administered. “There’s definitely going to be those temporal associations that aren’t necessarily causal associations,” he said.

It bears noting that the HPV vaccine is administered at ages 11 and 12 — a decade later than the childhood vaccinations that continue to cause so much consternation.

In a statement issued Tuesday, the American Academy of Pediatrics (AAP) admonished Bachmann, saying her claims about the HPV vaccine have “absolutely no scientific validity.” “Since the vaccine has been introduced, more than 35 million doses have been administered, and it has an excellent safety record,” AAP president O. Marion Burton said in the statement [PDF], noting that 6 million people contract HPV each year in the U.S., and 4,000 women die. “This is a life-saving vaccine that can protect girls from cervical cancer.”

The Global and Regional Asperger Syndrome Partnership also chimed in on Bachmann’s misguided comments, to Politico’s Ben Smith, and perhaps put it best:

“Congresswoman Bachmann’s decision to spread fear of vaccines is dangerous and irresponsible,” said Evan Siegfried, a spokesman for the Global and Regional Asperger Syndrome Partnership. “There is zero credible scientific evidence that vaccines cause mental retardation or autism. She should cease trying to foment fear in order to advance her political agenda.”

Meredith Melnick is a reporter at TIME. Find her on Twitter at @MeredithCM. You can also continue the discussion on TIME’s Facebook page and on Twitter at @TIME.

Correction [8 p.m.]: An earlier version of this post misstated that the Institute of Medicine report on vaccine safety did not include data on the HPV vaccine. In fact, the report did include such data and found no evidence linking the vaccine to mental retardation. An earlier version of this post also failed to clarify that Gov. Perry’s executive order to mandate HPV vaccination was subsequently overturned.

