The government is considering whether all girls, and possibly boys, aged 11 or 12 should be immunised against a sexually transmitted infection called human papillomavirus.
HPV can cause cervical cancer
What is HPV and why do we need a vaccine?
What is HPV?
There are more than 100 types of HPV and they are the most common sexually transmitted infection.
Around 80% of sexually active women can expect to have an HPV infection at some point in their lives.
Some forms of the HPV virus cause only genital warts, but others cause cancers including cancer of the neck of the womb or cervix.
Early trials have shown a jab can offer 100% protection against HPV strains linked to about 70% of cervical cancers.
About 3,000 women are diagnosed with this type of cancer every year in the UK.
However, even if a vaccine was in use, women would still need to be screened for cervical cancer.
This is because the vaccines do not prevent infection with all types of HPV, and it takes about 10 to 20 years after HPV infection for a cervical cancer to develop.
When will the vaccines be available?
One vaccine, called Gardasil, can already be purchased at private clinics. This vaccine, made by Merck, targets four HPV strains - cancer-causing 16 and 18, and the less dangerous 6 and 11 types that cause genital warts.
GSK is also developing a vaccine, called Cervarix, which targets HPV strains 16 and 18. Its licence is pending.
Who should be immunised?
Immunisation experts advising the government believe it would be most appropriate to vaccinate girls at the age of 11 or 12.
They are also considering whether boys of the same age should be vaccinated and if a catch-up campaign would be needed, and what age range that might cover.
The idea is to give it to children before they become sexually active and can catch HPV.
But the financial costs versus benefits has yet to be determined, and the idea could prove unpopular with parents. However, opinion polls suggest many would be happy to have their child immunised.
Gardasil is licensed for girls and boys aged nine to 15 and women aged 16 to 26. A course of three jabs costs just under £250.
Doctors say people outside of these age groups have been contacting them to get the vaccine. Many private clinics are offering it to gay men for about £450.
It is not yet clear whether people will need booster vaccines to keep them immune from HPV, or if the vaccine will stop HPV infection permanently.
Could the vaccine offer other benefits?
Experts are investigating whether it could protect against other cancers linked with HPV, like anal and penile cancer.
There are also ongoing trials to see how well the jab works in people who are HIV-positive, because this population is particularly susceptible to HPV-related diseases.