Unite has welcomed moves to provide boys as well as girls with the HPV vaccine.
The HPV vaccine is offered to girls aged 12 to 13 at school and is free for all girls until they turn 18, however it will now be offered to boys after a government advisory committee changed its advice.
The extended immunisation programme will be rolled out across Britain, after an update from the Joint Committee on Vaccination and Immunisation (JCVI) last week.
HPV is an umbrella term for a large group of viruses that can spread through any kind of sexual contact with a person who is already carrying it.
Most HPV infections will clear up by themselves, but can occasionally lead to a variety of health problems.
For boys these health problems can include cancer of the mouth, throat, anus and penis.
The HPV vaccine has been available for girls since 2008, with boys being expected to benefit through “herd protection”.
Health campaigners, however, have long argued that providing the vaccine to boys would add further protection.
Last July, the JCVI was criticised for not recommending the vaccine be offered to boys in its interim statement.
But now the committee says a combined programme is “highly likely to be cost-effective”.
Unite lead professional officer for health Obi Amadi said, “We think this is a sensible change. We had questioned why this was not being introduced to boys as it seemed to make no sense unvaccinated boys were a risk to other unvaccinated children.
“With more widespread vaccination we will be able to protect more of our young people from the group of associated viruses. It is important that parents understand this and ensure all of their children are protected.”