Campaigners have called for the NHS to vaccinate boys against the deadly human papilloma virus (HPV) after health chiefs accepted new evidence that it causes many more cases of cancer in men than previously thought.

Until recently, health bosses had argued it was ‘overwhelmingly’ likely that vaccinating teenage boys against HPV ‘would not be cost effective’.

Their conclusions were based on a computer model that predicted vaccinating them would not prevent large numbers of cancers.

Campaigners have called for the NHS to vaccinate boys against the deadly human papilloma virus (HPV) after health chiefs accepted new evidence that it causes many more cases of cancer in men than previously thought

But they have now conceded their old calculations were based on flawed information, The Mail on Sunday has discovered.

Health bosses have acknowledged that HPV causes up to five times as many cancers of the mouth and throat in men as had been estimated – and that the number of HPV-related cancer cases is rising faster than had been appreciated too.

Campaigners say the U-turn makes it far more likely Ministers will soon take the decision to approve vaccination of boys – as this paper has been urging – and ending an apartheid arrangement under which girls are routinely vaccinated.

The move would protect about 400,000 boys every year from the virus.

Last night, well-placed sources told the MoS a new computer model based on the updated figures ‘demolished’ the old assumptions. One said: ‘The new figures massively strengthen the case for vaccinating boys. It’s inconceivable for the policy not to change.’

Until recently, health bosses had argued it was ‘overwhelmingly’ likely that vaccinating teenage boys against HPV ‘would not be cost effective’

The revelation follows a meeting of the Joint Committee on Vaccinations and Immunisations last week. Its experts provide recommendations to Ministers about which groups of people should receive particular vaccines on the NHS.

The JCVI only makes its decisions public six weeks after such meetings – but will already have sent its recommendation to Steve Brine, the Minister in charge of vaccinations.

Oncologist Professor Chris Nutting, a head and neck cancer specialist at the Royal Marsden Hospital in London, said he understood the JCVI had ‘re-evaluated’ data on the cost effectiveness of vaccinating boys and were ‘very close to recommending’ it goes ahead.

He added: ‘This would be a major step towards preventing around 2,000 male cancer cases a year caused by this virus. I urge the NHS to confirm that a vaccination program will now go ahead.’

Girls have been prioritised because more women suffer from HPV-related cancers than men. Yet HPV also kills around 650 men a year, mainly due to oral cancers.

Public Health England said the JCVI would be carrying out an independent peer review of evidence before concluding its advice.