HPV (human papillomavirus): risks, testing and the HPV vaccine

What is HPV?

HPV is a group of more than 200 related viruses that infect the skin and mucous membranes. Around 40 types affect the genital area. They fall into two groups:

• low-risk types (mainly 6 and 11) – cause genital warts but not cancer;
• high-risk types (most importantly 16 and 18, as well as 31, 33, 45, 52, 58 and others) – if infection persists, they can cause precancerous changes and cancer.

According to the World Health Organization, almost all cases of cervical cancer are linked to high-risk HPV, with types 16 and 18 responsible for a large share. HPV also causes some cancers of the anus, vulva, vagina, penis and the back of the throat (oropharynx) – the last is becoming more common, especially in men.

How HPV spreads

HPV passes through direct skin-to-skin or mucosal contact during vaginal, anal or oral sex, and less often through intimate contact without penetration. Condoms reduce but do not completely remove the risk, as they do not cover all the skin that may be infected. HPV is not spread by toilet seats, swimming pools or shared cutlery.

Infection is often acquired soon after someone becomes sexually active. Because it usually causes no symptoms, people can carry and pass on the virus without knowing. A positive HPV result is not a sign of infidelity – the virus can stay unnoticed for many years.

Symptoms and how infection develops

Most people with HPV have no symptoms. The immune system clears around 90% of infections within one to two years. Problems arise when infection with a high-risk type persists for years. Cells on the cervix can then develop abnormal changes known as dysplasia or CIN (CIN1, CIN2, CIN3). It usually takes 10–20 years for persistent infection to progress to cancer, which leaves plenty of time to find and treat precancerous changes.

Factors that make persistence more likely include smoking, a weakened immune system (for example with HIV or after an organ transplant) and long-term use of some hormonal contraceptives. Low-risk types can cause genital warts – soft growths around the genitals or anus that are harmless but can be treated.

HPV testing and cervical screening

Screening aims to find high-risk HPV and precancerous changes before cancer develops. Tests include:

• HPV test – detects the genetic material of high-risk types; European guidance and the WHO now prefer it as the main screening test from around age 30, usually every five years if negative;
• cervical cytology (smear or Pap test) – looks at cells under a microscope; still widely used, particularly in younger women and in countries such as Bulgaria;
• colposcopy – a magnified examination of the cervix, with a biopsy if the HPV test or smear is abnormal.

A positive HPV test does not mean cancer; it means you need follow-up or further tests. Several countries now offer self-sampling kits at home. There is no routine HPV screening test for men. Read more about early detection of cancer.

Treatment

There is no medicine that kills the virus itself, but the changes it causes can be treated:

• mild changes (CIN1) – usually monitored, as they often clear by themselves;
• more significant changes (CIN2–3) – removed, most often by LLETZ/LEEP, a short procedure under local anaesthetic that cuts away the affected area of the cervix. Most women can still have children afterwards, although there is a slightly higher risk of premature birth;
• genital warts – creams, freezing, laser or surgical removal;
• HPV-related cancer – treated according to type and stage; see cervical cancer and cancer treatment.

The HPV vaccine

HPV vaccines are among the most effective cancer prevention tools available. The nine-valent vaccine protects against seven high-risk types and the two types that cause most genital warts. Countries with high vaccine uptake have seen large falls in precancerous changes and cervical cancer among vaccinated generations.

• When – ideally at 9–14 years, before sexual activity begins. The WHO supports a one- or two-dose schedule at this age; older people usually need two or three doses depending on age and product.
• Who – girls and boys; vaccinating boys protects them directly and reduces the spread of the virus.
• Adults – vaccination can be discussed later in life, including after treatment for precancerous changes, but the benefit is smaller if someone has already been exposed.
• Safety – hundreds of millions of doses have been given and safety is continuously monitored. The most common reactions are a sore arm, mild fever and, occasionally, fainting.

Many European countries, including Bulgaria and the UK, offer the vaccine free to children through national programmes. Ask your GP or school nurse about eligibility.

How to lower your risk

• make sure children are vaccinated on time;
• attend cervical screening even if you are vaccinated, because the vaccine does not cover every high-risk type;
• use condoms;
• stop smoking, which helps HPV persist;
• follow general advice on cancer prevention and attend regular health check-ups.

When to see a doctor

Contact your GP, sexual health clinic or gynaecologist if:

• you are overdue for cervical screening;
• you have bleeding after sex, between periods or after the menopause;
• you notice unusual discharge, pelvic pain or pain during sex;
• you find warts or growths in the genital or anal area;
• you have a persistent sore throat, hoarseness or a lump in the neck for more than three weeks.

If you receive an HPV-positive or abnormal smear result, try not to panic, but do not delay the follow-up test or colposcopy.

Testing and treatment abroad

Screening and vaccination are best done close to home, where results can be followed up regularly. If high-grade changes or cancer are found and you want a second opinion or treatment abroad, some patients from Europe choose large accredited hospitals in Istanbul with gynaecological oncology teams. Check accreditation, the doctor’s specialty and the written plan, and arrange follow-up at home. Organisers such as New City Clinic coordinate the hospital, doctor, hotel, transfers and an interpreter.