Different strains of HPV and what they mean

Reviewed by our clinical team

The human papillomavirus (better known as HPV) is a common virus that can affect the skin and mucous membranes of the body e.g. the mouth, vagina and anus.

Certain strains of HPV can cause cell changes and lead to cancer – most notably cancer of the cervix. This is why women over the age of 25 are invited to scheduled cervical screenings where their cervix is checked for high-risk types of HPV. 

Other strains of HPV aren’t a risk factor for cancer, but they can cause warts on the genitals and other parts of the body. To learn more, read on. 

How many strains of HPV are there and which areas of the body do they affect?

Genitals 

There are more than 100 different strains of HPV and around 40 directly affect the genitals. However, only around 13 of these strains are considered high-risk for cancer – the rest should be cleared by your body without causing complications. 

If you catch a high-risk strain of genital HPV you’ll have an increased risk of developing cancer, as these strains can sometimes lead to abnormal changes in the cells. High-risk HPV can cause: 

• Cervical cancer – more than 95% of cases are thought to be caused by high-risk HPV
• Anal cancer 
• Cancer of the penis 
• Cancer of the vulva and vagina

If you catch a low-risk strain of genital HPV you might not experience any symptoms or complications. However, there are low-risk strains that cause genital warts – in particular, strains 6 and 11. 

Genital warts are fleshy growths that develop on and around the genitals and anus. While this isn’t a life-threatening condition, the symptoms can be unpleasant and can occasionally cause complications in pregnancy, so it’s a good idea to go to a sexual health clinic or use a service like Online Doctor. 

Mouth and throat

The same high-risk HPV strains that affect the genitals can affect the mouth and throat too. If your mouth and throat are exposed to these strains, you’ll have an increased risk of developing cancer here. 

Hands and feet

Non-genital strains of HPV can cause warts around the body – most commonly on the hands and feet. 

Warts on the hands and feet are small, rough lumps, normally between 1mm and 1cm in size. There are lots of different types of wart, including common warts, plane (flat) warts and verrucas (also known as plantar warts). 

The good news is that warts aren’t usually harmful or painful – although verrucas can be sensitive when you put pressure on them. However, if you don’t like the way they look, or if they’re in an uncomfortable area, you can visit a pharmacist or your GP for advice. 

Which strains of HPV does the HPV vaccine protect against?

The modern HPV vaccine is called Gardasil 9. It protects against nine different strains of HPV: 6, 11, 16, 18, 31, 33, 45, 52 and 58. 

• Types 6 and 11 cause around 90% of cases of genital warts 
• Types 16 and 18 cause more than 80% of cases of cervical cancer 
• The remaining types cause an additional 15% of cases of cervical cancer

In addition to helping prevent genital warts and cervical cancer, this vaccine also offers protection against anal cancer, other types of genital cancer, and some cancers of the head and neck.

How is HPV spread? 

The human papillomavirus is spread through skin-to-skin contact. This is why strains that affect the genitals are spread through sex.

If your partner has genital HPV, you can catch it from them through the following sexual activities:

• Penetrative vaginal or anal sex 
• Oral sex 
• Sharing sex toys 
• Skin-to-skin contact of the genitals

Other types of HPV that cause warts around the body can be picked up through skin-to-skin contact or from contaminated surfaces. You are more likely to be infected if your skin is damaged or wet, which is why you can pick up verrucas by walking barefoot in communal areas that are moist or wet, like changing rooms and pools. 

How can I avoid catching HPV?

It’s hard to avoid catching genital HPV if you’re sexually active and having sex with new partners, as it spreads very easily even if you use condoms. This is why HPV is so common. The good news is, around 70% of new HPV infections clear within one year, and around 90% clear within two. 

However, if you’re worried about being exposed to HPV and developing genital warts or cancer, you can get the HPV vaccine. The vaccine is available to the following groups for free on the NHS:

• Girls and boys in Year 8 
• People under 25 who missed the vaccine in a UK school 
• Men up to 45 years old who have sex with men 
• Some trans men and women (8)

If you’re not eligible for a free vaccine you can get one privately through a trusted service like Online Doctor. Learn more here.

References

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/828868/Greenbook_chapter_18a.pdf
https://www.nhs.uk/conditions/human-papilloma-virus-hpv/
https://www.cancerresearchuk.org/about-cancer/causes-of-cancer/infections-eg-hpv-and-cancer/does-hpv-cause-cancer
https://www.who.int/news-room/fact-sheets/detail/human-papillomavirus-(hpv)-and-cervical-cancer
https://www.nhs.uk/conditions/genital-warts/
https://patient.info/skin-conditions/warts-and-verrucas-leaflet
https://www.nhs.uk/conditions/warts-and-verrucas/
https://www.nhs.uk/conditions/vaccinations/hpv-human-papillomavirus-vaccine/