Human papillomavirus (HPV) is not a single virus but a family of more than 200 related strains. Most cause no lasting harm, but a small number are linked to serious conditions including several types of cancer. The HPV vaccine used in the UK today protects against nine of these strains, targeting the ones responsible for the greatest disease burden. Understanding which strains are covered, and why those specific ones matter, helps make sense of what the vaccine can and cannot do.
What Is HPV and Why Does Strain Type Matter?
HPV strains are broadly categorised into low-risk and high-risk types. Low-risk strains typically cause benign conditions such as genital warts and, in rare cases, a condition called recurrent respiratory papillomatosis. High-risk strains can cause persistent infections that, over years or decades, lead to cancer.
Not all HPV strains carry the same risk, and not all behave the same way in the body. Most HPV infections, including infections with high-risk strains, are cleared naturally by the immune system without causing lasting problems. It is when high-risk strains establish persistent infection, usually defined as lasting more than two years, that the risk of cancer-related cell changes begins to rise.
The vaccine protects against specific strains selected because they account for the overwhelming majority of HPV-related cancers and a large proportion of genital wart cases. The selection of which strains to include is therefore central to how effective the vaccine is in practice.
The Gardasil 9 Vaccine: Which Nine Strains Does It Cover?
The HPV vaccine currently used in the UK is Gardasil 9, a nine-valent vaccine that replaced the earlier four-valent Gardasil and two-valent Cervarix in the national programme. As the name suggests, it protects against nine HPV strains. The table below sets out what each of those strains causes and why it was included.
| HPV Strain | Risk Category | Associated Conditions | Covered by Gardasil 9? |
| Types 16 and 18 | High-risk | Responsible for approximately 70% of cervical cancers; also associated with anal, oropharyngeal, vulval, vaginal, and penile cancers | Yes |
| Types 31, 33, 45, 52, and 58 | High-risk | Together responsible for approximately 15% of cervical cancers and contribute to other HPV-related cancers | Yes |
| Types 6 and 11 | Low-risk | Responsible for approximately 90% of genital wart cases; also cause recurrent respiratory papillomatosis | Yes |
| Other strains (190+ types) | Low and high-risk | Remaining HPV strains not covered by the vaccine, some of which can also cause HPV-related disease | No |
Note: Percentages cited reflect published estimates at the time of writing and may vary slightly between sources. The vaccine does not protect against all HPV strains, and cervical screening remains important for people with a cervix even after vaccination.
HPV Vaccine Benefits: What Conditions Does It Protect Against?
The HPV vaccine benefits extend across multiple conditions, not just cervical cancer. The nine strains covered by Gardasil 9 are responsible for significant disease burden across several cancer types and one of the most common sexually transmitted infections in the UK.
Cancer Prevention
By targeting the two highest-risk strains (types 16 and 18) alongside five additional high-risk strains (31, 33, 45, 52, and 58), Gardasil 9 covers the strains responsible for the vast majority of HPV-related cancers. The cancers against which vaccination provides meaningful protection include:
- Cervical cancer — the most common HPV-related cancer in the UK; Gardasil 9 covers strains responsible for approximately 85% of cases.
- Anal cancer — types 16 and 18 are responsible for the majority of cases; vaccination offers protection for all genders.
- Oropharyngeal cancer (throat and tonsil cancers linked to HPV) — incidence is rising in the UK, particularly in men; type 16 is the primary driver.
- Vulval, vaginal, and penile cancers — less common but meaningfully reduced by vaccination against high-risk strains.
It is important to note that the vaccine works best before exposure to the strains it covers. It does not treat existing HPV infections or reverse cell changes that have already occurred.
Genital Warts
HPV vaccine genital warts protection is provided by strains 6 and 11, which together cause around 90% of genital wart cases in the UK. Genital warts are one of the most commonly diagnosed sexually transmitted infections and, while not associated with cancer, can cause significant discomfort and psychological distress. The inclusion of these two low-risk strains in Gardasil 9 means that the vaccine protects against the most prevalent cause of genital warts in addition to cancer-related strains.
HPV Vaccine Types: How Has the UK Vaccine Changed Over Time?
Understanding the HPV vaccine types matters because a significant number of adults received earlier versions of the vaccine at school and may not have the broader protection that Gardasil 9 provides.
The UK school programme originally used Cervarix (a two-valent vaccine covering only types 16 and 18) from 2008 to 2012, and then Gardasil (a four-valent vaccine covering types 6, 11, 16, and 18) from 2012 to 2022. Gardasil 9 has been the UK programme vaccine since 2022, adding five additional high-risk strains to the four covered by its predecessor.
Adults who received Cervarix or four-valent Gardasil at school have partial but not complete coverage compared to Gardasil 9. Whether supplementing earlier vaccination with Gardasil 9 is worthwhile is an individual clinical decision; speak to a pharmacist for personalised guidance.
Does the HPV Vaccine Replace Cervical Screening?
No. This is one of the most important points to communicate about the HPV vaccine. Even though Gardasil 9 covers the strains responsible for approximately 85% of cervical cancers, around 15% of cervical cancers are caused by strains not included in the vaccine. Cervical screening (smear tests) remains an essential component of cervical cancer prevention for people with a cervix, regardless of vaccination status.
Vaccinated individuals should still attend cervical screening when invited, as the invitation schedule is set by the NHS and is not adjusted based on vaccination history.
How to Access the HPV Vaccine in the UK
The HPV vaccine is available through the NHS school immunisation programme and, for eligible groups, through a GP or sexual health clinic. For those outside the NHS programme, private vaccination with Gardasil 9 is available through registered pharmacies.
At Touchwood Pharmacy, our pharmacists can advise on whether the HPV vaccine is appropriate for your circumstances, explain what the Gardasil 9 vaccine covers, and administer the vaccination privately.
Book your appointment with our experts at Touchwood Pharmacy for personalised vaccination advice and access to the HPV vaccine in the UK.
This article is for informational purposes only and does not constitute medical advice. The HPV vaccine does not protect against all HPV strains. Cervical screening remains important for people with a cervix even after vaccination. Always consult a qualified healthcare professional before making decisions about vaccination.
Frequently Asked Questions (FAQ’s)
How many HPV strains does the UK vaccine protect against?
The current UK HPV vaccine, Gardasil 9, protects against nine strains of human papillomavirus: types 6, 11, 16, 18, 31, 33, 45, 52, and 58. These nine strains are responsible for approximately 90% of genital wart cases and around 85% of cervical cancers, as well as contributing significantly to other HPV-related cancers including anal, oropharyngeal, vulval, vaginal, and penile cancers.
Does the HPV vaccine protect against genital warts?
Yes. The Gardasil 9 vaccine includes protection against HPV types 6 and 11, which together cause approximately 90% of genital wart cases in the UK. This is one of the notable benefits of Gardasil 9 over earlier HPV vaccine types that did not include these low-risk strains. Both men and women benefit from this protection.
If I had the HPV vaccine at school, am I protected against all nine strains?
It depends on which vaccine you received. The UK school programme used Cervarix (types 16 and 18 only) from 2008 to 2012, and four-valent Gardasil (types 6, 11, 16, and 18) from 2012 to 2022. Gardasil 9, covering nine strains, has been used since 2022. If you received an earlier vaccine, you have partial but not complete protection compared to Gardasil 9. Discuss with a pharmacist whether additional vaccination would be beneficial for your circumstances.
Can the HPV vaccine treat an existing HPV infection?
No. The HPV vaccine is preventive, not therapeutic. It works by training the immune system to recognise and fight HPV strains before exposure. It does not treat existing infections or reverse cell changes that have already occurred as a result of HPV. For this reason, vaccination is most effective when given before sexual activity begins, though adults can still benefit from protection against strains they have not yet encountered.
Do men benefit from the HPV vaccine?
Yes. The HPV vaccine protects against anal cancer, oropharyngeal cancer, penile cancer, and genital warts in men. The UK school immunisation programme has included boys since September 2019. Men who have sex with men can also access NHS HPV vaccination through sexual health clinics. Men outside these NHS groups who want protection can access private vaccination through a registered pharmacy.
How long does the HPV vaccine last?
Long-term follow-up data from clinical trials suggest that protection from the Gardasil 9 vaccine is durable, with studies showing sustained antibody levels over at least ten years. Whether a booster will eventually be needed for long-term protection is an area of ongoing research. Current UK guidance does not routinely recommend boosters for people who have completed the standard course.
