CALGARY-- Concerned parents and doctors are attempting to persuade the Calgary Catholic School Board and the city's Roman Catholic bishop to lift a ban that blocks students from being vaccinated against HPV.

HPV vaccine programs have been available to girls in Grades 5 and 9 since 2007. Experts say they are also a benefit to boys, who can transmit the virus even if not affected by it.

But the programs are still a tough sell in some parts of the country.

The vaccination protects against four strains of human papillomavirus (HPV), the primary cause of genital warts and the agent behind about 70 per cent of cervical cancers.

The Catholic board blocked the vaccination in its schools in 2008, making Calgary the only major Canadian city that doesn't offer the vaccine to all students.

"It's important to stress bad things can happen and parents ought to protect their children against foreseeable, possible bad things," Juliet Guichon, a legal scholar and assistant professor of community health sciences at the University of Calgary, said Monday.

Guichon, who is Catholic, made sure her children received the vaccination when it wasn't available in school.

"We are coming forward to ask trustees to put children first and to stress that publicly funded schools are owned by the public," she added.

Bishop Fred Henry, a staunch opponent of administering the vaccine, said the issue is that for Catholics, sexuality is a gift, sexual activity is appropriate only within marriage and abstinence is the best protection against risks of disease.

"If we don't attempt to change sexual behaviour that is responsible for transmission of the HPV, but attempt to solve the problem by getting a series of shots, then we don't have to exercise self-control, nor develop virtue, but can use medicine to palliate our vices," Henry said in an email to The Canadian Press Monday night.

"The technological solution requires no change in behaviour. It does not really address the cause but masks it, and actually undermines efforts to achieve the most efficient solution."

Henry also said that "parents, physicians, educators and governing bodies should adopt a holistic health-oriented approach that addresses sexual attitudes and behaviours recommending delayed genital sexual activity."

"For Catholics, there is no such thing as a purely "health" issue," Henry said.

"All activities proposed for a Catholic school need to be assessed in the light of our faith and doctrine. This is self-evidently necessary in the case of a vaccine against a disease that is transmitted by sexual activity, which impacts not only the physical but also the spiritual, psychological and moral well-being of an individual."

Pediatrician Dr. Ian Mitchell from the University of Calgary said his group attempted to meet with Bishop Henry to make its case.

"The Catholic School Board continues to tell us that they get advice from Bishop Henry, so we have been in touch with Bishop Henry," Mitchell said. "We've invited him to presentations. We've offered to meet with him to answer questions.

"He's refused. I can't dance with a partner who won't come to the dance floor."

Guichon said publicly funded Catholic boards in Yellowknife, the Ontario region of Halton and eight school districts in central and southern Alberta continue to ban the vaccine.

Despite the moral opposition to its use, Guichon believes medical proof attesting to its benefit is overwhelming

"It's hard to debate this because it's not grounded in evidence or rationality," Guichon said.

"It's hard to know what to say because, as I understand the argument, it's cause and effect. You give the vaccine and the children will become promiscuous. What we see anecdotally is that the children don't jump into bed -- they go out for recess."

Dr. Susan Bornemisza, who has a practice in Calgary, said she usually diagnoses one case of HPV infection every day.

"It's pretty devastating for them when they find out that they have it. They're pretty sad and upset and when they find out there's a vaccination they can get to stop it from happening, they're pretty excited about that."