Vaccination and STD Prevention: What You Need

HPV vaccination is the most effective STD prevention tool available — more effective than condoms for the infections it covers, and the only intervention that can prevent HPV-related cancers before exposure occurs. Two vaccines are currently available globally, with Gardasil 9 covering nine strains responsible for approximately 90% of genital warts and 90% of HPV-related cancers. The case for vaccination, and for understanding what it does and does not cover, is straightforward.

• Gardasil 9 protects against HPV strains 6, 11, 16, 18, 31, 33, 45, 52, and 58

• HPV vaccination has reduced cervical precancer rates by over 80% in countries with high adolescent uptake

• Vaccination is recommended up to age 26 routinely, and up to age 45 after individual risk discussion

• Hepatitis B is sexually transmitted and preventable through a separate, highly effective vaccine

• No vaccines currently exist for HIV, herpes, chlamydia, gonorrhea, or syphilis — though research is ongoing

HPV Vaccine: The Most Impactful STD Prevention Tool

Human papillomavirus is the most common STD globally, affecting the majority of sexually active adults at some point in their lives. Most infections clear spontaneously, but high-risk strains — particularly types 16 and 18 — cause the majority of cervical cancers as well as cancers of the throat, anus, penis, vagina, and vulva. Low-risk strains (6 and 11) cause genital warts.

Gardasil 9, the current vaccine, protects against nine strains responsible for approximately 90% of HPV-related cancers and 90% of genital warts. Vaccination before exposure to these strains provides the highest protection. The CDC recommends routine vaccination at age 11–12, with catch-up vaccination through age 26. Adults aged 27–45 can discuss vaccination with their clinician, particularly if they are not in long-term monogamous relationships. The population-level impact of high-coverage HPV vaccination programmes has been dramatic — countries with near-universal adolescent vaccination have seen cervical cancer rates fall by more than 80%.

Who should get the HPV vaccine?

Everyone up to age 26 who has not been previously vaccinated. Men who have sex with men (MSM) are at particular risk of HPV-related anal and throat cancers and should prioritise vaccination regardless of sexual history. People who are immunocompromised have reduced vaccine effectiveness and should discuss timing and dosing with their clinician. For adults aged 27–45, vaccination provides some benefit for strains not yet acquired, though the benefit decreases as the number of prior sexual partners increases. Getting vaccinated at age 35 is better than not getting vaccinated at all.

How many doses?

Two doses are given 6–12 months apart for people who start vaccination before age 15. Three doses are given over 6 months for those starting at age 15 or older. If you started vaccination and did not complete the series, completing it — even years later — is worthwhile. You do not need to restart the series from scratch.

Hepatitis B Vaccine

Hepatitis B is a bloodborne and sexually transmitted viral infection. It spreads through sexual contact, sharing needles, and from mother to baby at birth. Approximately 10% of adult infections become chronic, with risk of cirrhosis and hepatocellular carcinoma over decades. Globally, hepatitis B causes more deaths annually than HIV.

The hepatitis B vaccine is highly effective — protective in over 95% of recipients — and is recommended for all unvaccinated adults. The standard course is three doses over 6 months, though an accelerated two-dose schedule (Heplisav-B) is now available for adults. Checking immunity status with a blood test (hepatitis B surface antibody titre) is a sensible starting point if you are unsure of your vaccination history. Vaccination after potential exposure (combined with hepatitis B immune globulin) is also effective if given promptly.

Despite being available since 1982 and part of routine infant schedules in most high-income countries since the 1990s, a significant proportion of adults born before universal vaccination remain unvaccinated. If you were born before the 1990s and have not specifically checked your immunity, doing so is worthwhile.

Hepatitis A Vaccine

Hepatitis A is primarily transmitted through contaminated food and water, but can also transmit through oral-anal sexual contact. It causes acute liver illness and, in people with existing liver disease, can be severe. The hepatitis A vaccine is given as a two-dose course and provides lifelong protection. A combination hepatitis A/B vaccine (Twinrix) allows both to be given in a single series. Hepatitis A vaccination is recommended for MSM, people who inject drugs, people with chronic liver disease, and international travellers to endemic regions.

Vaccines in Development

No vaccines currently exist for HIV, herpes simplex, chlamydia, gonorrhea, or syphilis, though research is active across all of these. The most advanced are an mRNA-based herpes vaccine in early clinical trials and studies suggesting the meningococcal B vaccine (MenB) provides partial cross-protection against gonorrhea. HIV vaccine research, while decades-old, has been revitalised by mRNA technology. None of these are at the point of clinical recommendation. The absence of vaccines for these infections is precisely why condoms, regular testing, and PrEP for HIV remain important alongside HPV and hepatitis B vaccination.

Tips

• Check your HPV vaccination history — if you received fewer than the recommended doses, completing the series adds meaningful protection.

• Check your hepatitis B immunity — a simple blood test confirms whether you are protected. If not, vaccinate.

• Vaccination does not replace other prevention — HPV and hepatitis B vaccines do not protect against chlamydia, gonorrhea, HIV, herpes, or syphilis. Condoms and regular testing remain essential.

• Consider hepatitis A vaccination if you have oral-anal sexual contact, chronic liver disease, or travel internationally.

• Vaccinate even if already sexually active — you are very unlikely to have been exposed to all nine strains covered by Gardasil 9, so vaccination provides meaningful protection even after sexual debut.

Frequently Asked Questions

If I am already sexually active, is the HPV vaccine worth getting?

Yes. Even with a prior sexual history, it is very unlikely you have been exposed to all nine strains in Gardasil 9. The vaccine protects against strains not yet acquired. The benefit is greatest for those with fewer prior partners, but it is meaningful for adults up to age 45.

Do men need the HPV vaccine?

Yes. HPV causes anal cancer, penile cancer, and throat cancer in men, as well as genital warts in all sexes. The vaccine is recommended for all males up to age 26 and can be considered up to age 45. MSM are at particularly high risk of HPV-related anal cancer and should prioritise vaccination.

Is hepatitis B vaccination available for free?

In the UK, hepatitis B vaccination is available free through the NHS for people at risk, including MSM, people who inject drugs, and sex workers. In the US, it is covered by most insurance plans under the ACA preventive care mandate and available at no cost through community health centres for those without insurance.

Can I get vaccinated if I already have HPV?

Yes. Existing HPV infection with one strain does not prevent vaccination from protecting against other strains. The vaccine does not treat existing infections, but it provides meaningful protection against strains not yet acquired.

Does the HPV vaccine protect against all cervical cancers?

No — it protects against the strains responsible for approximately 90% of HPV-related cervical cancers. A small proportion of cervical cancers are caused by strains not covered by the vaccine. This is why cervical screening (Pap smears/colposcopy) remains important even for vaccinated individuals.

Get Vaccinated and Get Tested

Vaccination covers a specific subset of STD-related infections. For everything else, regular testing is the essential complement. Fast, confidential testing is available at sexual health clinics and online.

Related reading: Understanding HPV · Hepatitis B: Hidden Dangers · How Often Should You Get Tested? · Can You Have an STD With No Symptoms?