CALGARY -- Calgary's Catholic school district will review its policy against allowing students to be vaccinated for the virus that causes cervical and other types of cancers.

Four years ago, the district said no to the HPV vaccine, a position that was strongly supported by Calgary Bishop Fred Henry, who opposed the vaccine being given in Catholic schools on moral and religious grounds.

The district's board of trustees now says because of recent medical studies it will consult with parents about offering the vaccine to Grade 5 girls.

"At the end of the day, the information will come back to the board and the board will make a decision that will be heavily informed by parental input," Mary Martin, chairwoman of the board of trustees said Thursday.

"It is conceivable that this vaccine will be administered in our schools or, pending the direction of our parents, they may direct us to stay the course."

HPV is transmitted through sexual activity and can cause penile, vaginal and neck cancers as well as genital warts.

The Calgary Catholic district is the only school board in a major Canadian city that doesn't allow students to receive the HPV vaccination at school.

Other publicly funded Catholic boards in Yellowknife, the Ontario region of Halton and school districts in central and southern Alberta have also banned the vaccine.

Earlier this month, researchers published a study in the journal Pediatrics that said the HPV vaccine has not been linked to promiscuity in girls.

The study was funded by the Kaiser Permanente health management organization in the United States and Emory University.

It followed 1,398 girls aged 11-12 in Georgia during the first 18 months after the Gardasil HPV vaccine became available.

"We saw no increase in pregnancies, sexually transmitted infections or birth-control counselling -- all of which suggest the HPV vaccine does not have an impact on increased sexual activity," Robert Bednarczyk, an epidemiologist and lead author of the study, said.

On Oct. 20, 2008, Bishop Henry praised school districts that voted against Alberta's HPV vaccination program. At the time, he wrote that it should be up to parents to decide if their child should be vaccinated. He said Catholic schools have a different responsibility of living the faith and following its teachings, including no sex outside of marriage.

"Arguments in favour of widespread availability of the HPV vaccine are emblematic of a collective loss of nerve in the face of powerful libertine pressures within our culture," he wrote in an article called "Getting It Right" that is posted on the Calgary Catholic diocese web site.

In an email Thursday, Henry said he still supports the board's current policy against the HPV vaccine, but he also supports the review.

He cited the lack of a consistent policy and practice by Catholic school districts in Alberta and threats of legal action for his new position.

"I am also supporting the recent motion of the trustees to seek the counsel of our parent school councils as to whether they continue to support the course of action outlined in the 2008 motion or would they advise us to offer the vaccine in our Catholic schools," he wrote.

A group called HPV Calgary has threatened to launch a legal challenge against the Calgary Catholic school district over its anti-vaccine policy.

Juliette Guichon, a University of Calgary community health professor, said the group hopes the board will move quickly to allow girls to be vaccinated, but it will keep raising money for its lawsuit and will file its statement of claim as soon as it reaches its $100,000 fundraising goal.

"We are cautiously optimistic that the board will open the school doors to the HPV vaccine," she said. "If there is anything we can do to help them focus on the best interests of the children, we would like to do that."

Guichon said if the board does change its policy, Alberta Health Services should be allowed to offer the free vaccine to any girl in the Calgary Catholic school system who missed getting the series of three shots over the past four years.

Martin said there is no set timeline for the school board's review, but it could take weeks rather than months.