Video report by ITV News Correspondent Martha Fairlie
Boys across the UK are to be offered the HPV vaccine following a review of how effective it is at slashing the incidents of a range of cancers.
Health officials have announced boys aged 12 to 13 will be offered the jab from the start of the next school year, in September.
Girls of a similar age already routinely receive the vaccine and the news relating to boys comes after a huge review of the effectiveness of the HPV vaccine concluded it slashes the incidents of cervical cancers significantly.
The treatment was linked to a huge reduction in the two types of HPV – 16 and 18 – which cause 70% of cervical cancers
The researchers looked at studies involving 60 million people and are now recommending the HPV vaccine be rolled out.
So what is HPV and what's the story behind the vaccine?
What is HPV?
Human papillomavirus is very common group of viruses that affects the skin. Most people will, at some point, catch a HPV.
HPV infections do not usually cause any symptoms, and most people will not know they're infected.
There are more than 100 different types of HPV, and about 40 of them affect the genital area.
While many do not cause any issues for people, some types are "high risk" because they are linked to the development of cancers, such as cervical cancer, anal cancer, genital cancers, and cancers of the head and neck.
Others are linked to less serious complaints such as verrucas.
How is HPV spread?
Many types of HPV affect the mouth, throat or genital area, says the NHS, and they're easy to catch - you do not need to have penetrative sex.
You can get HPV from:
any skin-to-skin contact of the genital area
vaginal, anal or oral sex
sharing sex toys
And, you do not have to have multiple sexual partners to get an HPV.
While most people will get rid of it naturally without treatment, some infected with one of the "high risk" viruses will not be able to clear it.
The risk particularly acute for some women infected with a high-risk type of HPV.
Over time, this can cause abnormal tissue growth as well as other changes in the cells of their cervix, which can lead to cervical cancer if not treated.
What types of cancers and conditions is HPV linked with?
As well as being most often linked with cervical cancer, HPV is also linked to:
cancer of the penis
some cancers of the head and neck
Infection with other types of HPV may cause:
genital warts – small growths or skin changes on or around the genital or anal area; they're the most common viral sexually transmitted infection (STI) in the UK
skin warts and verrucas – not on the genital area
warts on the voice box or vocal cords (laryngeal papillomas)
What's the story about the vaccine?
The NHS HPV vaccination programme uses a vaccine called Gardasil, which protects against 4 types of HPV: 6, 11, 16 and 18.
Between them, types 16 and 18 are the cause of most cervical cancers in the UK (more than 70%).
These types of HPV also cause some anal and genital cancers, and some cancers of the head and neck.
HPV types 6 and 11 cause around 90% of genital warts, so using Gardasil helps protect girls against both cervical cancer and genital warts.
It's important to realise the HPV vaccine does not protect against other infections spread during sex, and it's not birth control.
Experts believe the vaccine is effective for at least 10 years, but it does not cover all types of HPV that cause cervical cancer so women should still go for regular smear tests.
Who can get the vaccine?
The first dose is routinely offered to girls aged 12 and 13 in school Year 8.
The second dose is normally offered six to 12 months later (in school Year 8 or Year 9).
It's important to have both doses of the vaccine to be fully protected.
Girls who did not have the vaccine during school years can still get it on the NHS up to the age of 25 - but, after the age of 15, they'll need three doses as they do not respond as well to two as younger girls do.
Since a UK-wide immunisation scheme for girls aged 12 and 13 was introduced a decade ago, researchers have reported a reduction of up to 90% of instances of pre-cancerous cells being discovered at smear tests aged 20.
In July 2018, it was decided that boys aged 12-13 should also receive the HPV vaccine.
In July 2019, it was confirmed that boys will be given the vaccine, starting in the new school year in September.
It will be available in schools across the UK but, as health policy is devolved, the exact timings and availability may differ across the regions.
The NHS has reported that a catch-up programme for older boys "is not necessary as evidence suggests they're already benefiting greatly from the indirect protection (known as herd protection) that's built up from 10 years of the girls' HPV vaccination programme".
Why is the vaccine administered so early?
HPV infections can be spread by skin-to-skin contact - fingers, hands, mouth - just touching, not full sex, so it's important to vaccinate before youngsters become sexually active.
It's not clear how beneficial the vaccine is for gay men.
However, from April 2018, men aged up to 45, who have sex with men, became eligible for free HPV vaccination on the NHS through sexual health clinics and HIV clinics in England.