About 80 per cent of adults are infected, and it is now known to cause cancers of the cervix, anus, genitals, head and neck – often decades after initial infection.
The NHS is facing legal action from the Throat Cancer Foundation on grounds that the current "vaccine apartheid" policy amounts to gender discrimination.
But while our campaign has raised awareness of HPV, it has also highlighted a second form of discrimination – between those able to afford to vaccinate their sons privately, and those who can't.
Boots and Superdrug both offer vaccination for boys. For those aged up to 14, who require two doses, this costs $600, rising to $872 for older males, who need three doses – a price many times higher than the $58 to $77 per patient experts say vaccinating all boys in school year 8 would cost the NHS.
However, both chains have now run out – and makers MSD says new supplies will not be available until July.
The reason, MSD said, is that it has seen an increase in demand for HPV vaccines from UK pharmacies.
Boots apologised for the shortage, saying that for the time being, no new online bookings are being accepted.
An official decision on whether to extend the jab to boys in schools is pending.