US presidential hopeful's claim that the vaccine was responsible for 'mental retardation' is criticised by medical professionals

The Republican party's uneasy relationship with science was thrust into the spotlight again after social conservative Michele Bachmann claimed a well-tested anti-cancer vaccine was responsible for "mental retardation".

Bachmann's comments were condemned by medical professionals, including the highly respected American Academy of Pediatrics, which said "this is a life saving vaccine that can protect girls from cervical cancer", while even rightwing talkshow host Rush Limbaugh criticised Bachmann's scare tactics.

During the Republican presidential candidates debate on Monday, Bachmann attacked the frontrunner, Texas governor Rick Perry, for his 2007 order to vaccinate young girls against human papillomavirus (HPV), although Perry's order was never introduced and contained an opt-out clause. (You can watch the clip from the debate here.)

Assailing Perry for forcing HPV vaccinations on "little girls who have a potentially dangerous reaction to this drug", Bachmann then told NBC's Today show on Tuesday:

I had a mother last night come up to me here in Tampa after the debate. She told me that her little daughter took that vaccine, that injection, and she suffered from mental retardation thereafter. It can have very dangerous side effects.

Without naming Bachmann, Dr Marion Burton, the president of the American Academy of Pediatrics, issued a statement strongly defending the HPV vaccine: "The American Academy of Pediatrics would like to correct false statements made in the Republican presidential campaign that HPV vaccine is dangerous and can cause mental retardation. There is absolutely no scientific validity to this statement. Since the vaccine has been introduced, more than 35m doses have been administered, and it has an excellent safety record."

Use of the vaccine – marketed by Merck as Gardisil – is backed by the US government's Centre for Disease Control and Prevention, while the Federal Drug Authority found in extensive clinical studies that Gardisil was unusually effective, without serious side effects.

Rush Limbaugh chimed in, saying on his daily syndicated radio show that Bachmann had gone too far:

Michele Bachmann, she might have blown it today. Well, not blown it – she might have jumped the shark today. If she'd just left it alone on this vaccination thing from last night.

She's now out saying that this Gardasil drug now causes mental retardation. Somebody in the audience came up to her and told her that – that's jumping the shark on this. There's no evidence that the vaccine causes mental retardation. That's a shame.

Meanwhile, it has emerged that Bachmann recorded no opposition to the mandatory use of the Hepatitis B vaccination in Minnesota, where she served for five years in the state legislature before being elected to Congress.

Like HPV, Hepatitis B is spread through intercourse. Yet while the Hepatitis B vaccine is uncontroversial, social conservatives such as Bachmann strongly oppose the use of the HPV vaccine as endorsing promiscuity.

The American Academy of Family Physicians recommends that girls receive the HPV vaccine around the age of 11 or 12, when the vaccine produces the best immune response in the body and before the start of sexual activity.

In the US, nearly 6 million people are infected with HPV each year, while 4,000 women die from cervical cancer.

Regarded as an staunch conservative by any measure, Perry's mandatory vaccination programme – which would have allowed parents to opt out – has been seized upon by his rivals.

Perry defended his intended order as sound policy to prevent cancer, saying: "Texas is a place that, day in and day out, protects life."

But Perry's enthusiasm for protecting life doesn't extend to death row of Texas's prisons, where Perry has approved the execution of 234 people.