TORONTO - The trepidation and distrust HPV vaccines have faced from some quarters are a disappointment to the scientist whose discovery of the link between human papillomaviruses and cervical cancer laid the groundwork for the vaccines.

Dr. Harald zur Hausen, co-winner of this year's Nobel prize for medicine, admitted in an interview Monday that the negative reaction of some parents in North America and Europe to the vaccines perturbs him.

"It is a little bit dismaying," said zur Hausen, who has no financial stake in either of the two existing HPV vaccines and receives no royalties from the vaccine manufacturers.

The German scientist said that while no vaccine is risk-free, he is persuaded the HPV vaccines are as safe as the standard immunizations given to most children.

"From the information which I have, more than 14 million girls have been vaccinated (against HPV) by now. The number is large," he said by phone from London, Ont.

"There have been very carefully conducted clinical trials. . . . And the cases of severe reaction after vaccination upon careful examination didn't seem to turn out to be indicative that they had any connection with the vaccination. So for all these reasons, it's a little bit disconcerting."

Earlier this month the Nobel Foundation named Zur Hausen a co-winner of its 2008 prize for medicine. The former scientific director of the German Cancer Research Centre in Heidelberg, Germany, zur Hausen shared the prize with two French researchers credited with discovering the human immunodeficiency virus or HIV, Dr. Luc Montagnier and Dr. Francoise Barre-Sinoussi.

In April, zur Hausen was named among this year's crop of Gairdner winners. The Canadian prizes are often referred to as the "baby Nobels" because so many Gairdner recipients - 73 to date - have gone on to win the world's most coveted science prize.

Zur Hausen is in Ontario this week to give a Gairdner lecture at the University of Western Ontario, in London. The Gairdner awards ceremony will be held Thursday in Toronto.

All 10 of the provinces - though none of the territories - have instituted HPV vaccine programs for adolescent girls since the federal government announced in the 2007 budget that it was making $300 million available to kick start HPV vaccination efforts.

But while governments have embraced the vaccines, public response has been mixed. A number of parents - and even some social commentators - have questioned the speed with which public funding was made available.

Some critics have raised concerns about the long-term safety and efficacy of the vaccines, suggesting the fact that the programs target girls only - even though boys can spread the viruses and can develop penile and anal cancers caused by the same viruses - has turned girls into guinea pigs.

Still others argue vaccinating young girls against a sexually transmitted disease could be interpreted as encouraging them to become sexually active or could give them a false sense of safety that might induce them to forgo condoms while having sex.

It is not yet clear what percentage of parents nationally agreed to allow their daughters to receive the three shots needed for HPV vaccination. But early figures for the 2007-08 year in Ontario - the first year of the program - suggest around 53 per cent of eligible girls received at least the first shot, said Andrew Morrison, a spokesperson for the Ontario Ministry of Health.

In the United States, a recent report from the Centers for Disease Control estimates that about 23 per cent of American girls aged 13 to 17 had received the full series of HPV shots.

Still, zur Hausen - who had to wait a couple of decades to see his team's discovery translated into vaccines - suggested he's confident that with time the public will be more accepting of HPV vaccination.

"I think it's really a matter of public education and of consciousness about the risks of acquiring these infections over the long run, which I think should be a really persuasive argument for introducing or implementing the vaccine," he said.

"But it takes time. It's something which is not quickly achieved."

Two HPV vaccines - Merck's Gardasil and GlaxoSmithKline's Cervarix - are currently marketed around the world, in 108 and 80 countries respectively.

Gardasil protects against HPV viruses 16 and 18, which cause 70 per cent of cervical cancers plus two others - HPV 6 and 11 - that cause 90 per cent of all cases of genital warts. Cervarix protects only against viruses 16 and 18, the cancer causing viruses.

To date Gardasil has the Canada and U.S. markets to itself; Cervarix is still working its way through the regulatory pipelines of the two countries.

The World Health Organization estimates there are roughly 500,000 new cases of cervical cancer a year and about 250,000 women a year die from the disease. In Canada, it's estimated 1,300 women will be diagnosed with cervical cancer this year and 380 women will succumb to the disease.