HPV vaccination: how many doses are needed and for whom?

Vaccination against human papillomavirus (HPV) is one of the most effective ways to prevent HPV-related diseases, including cervical cancer.

For a long time, vaccination was administered according to two- or three-dose schedules. However, new data show that one dose may be sufficient for some groups of people.

At the same time, a single-dose schedule is not suitable for everyone. The number of doses depends primarily on age at the time of vaccination and immune status.

Why was the single-dose schedule introduced?

The change in approach was based on data from studies of vaccine efficacy and immunogenicity.

One large study in Costa Rica included more than 20,000 girls aged 12–16 years. One and two doses provided very high protection against persistent HPV types 16 and 18 infection for five years.

These findings became part of the evidence base supporting the use of a single-dose schedule in certain groups of patients.

Single-dose vaccination also has an important practical advantage: fewer injections and visits to the doctor may make vaccination more accessible and increase vaccination coverage.

Who may need only one dose?

According to WHO recommendations, vaccination with one dose is acceptable for immunocompetent people in certain age groups.

WHO recommends:

• girls aged 9–14 years — 1 or 2 doses;
• girls and women aged 15–20 years — 1 or 2 doses;
• women over 21 years of age — 2 doses with a 6-month interval.

The approach is different for people with weakened immune systems.

It is important to consider that national recommendations may differ. For example, in the United States, CDC recommendations call for two doses for most people who start vaccination before age 15, and three doses for those who start vaccination at age 15 or older, as well as for people with weakened immune systems.

Therefore, the vaccination schedule is best determined individually.

Who needs two or three doses?

A more complex schedule may be required for:

• people starting vaccination at an older age;
• people with weakened immune systems;
• people with HIV;
• patients who have already started vaccination according to a multi-dose schedule.

WHO recommends at least two doses for people with weakened immune systems, and three doses when possible.

Why is it better to get vaccinated during adolescence?

The HPV vaccine prevents new infection but does not treat an existing infection.

Therefore, vaccination provides the greatest benefit before exposure to the virus. This is why adolescents are the primary target group for vaccination.

However, becoming sexually active does not mean that vaccination is no longer useful. A person may have been exposed to one type of HPV while still having no immunity to other types covered by the vaccine.

Do you need to be tested for HPV before vaccination?

No, routine HPV testing is not required before vaccination.

There is also no need to test for antibodies to determine whether vaccination is needed.

Vaccination should not be postponed simply because preliminary testing has not been performed.

Does vaccination replace screening?

No.

Even after vaccination, it is necessary to undergo recommended cervical cancer screening according to age and current guidelines.

Vaccination and screening serve different purposes: vaccination prevents most HPV-related infections, while screening helps detect precancerous changes at an early stage.

Key message

Single-dose HPV vaccination has become possible thanks to accumulating evidence on efficacy and immune response.

For some immunocompetent adolescents and young adults, one dose may be sufficient, but there is no universal schedule for everyone.

Age, immune status, and previous vaccination are important when determining the number of doses.

If you are unsure whether you or your child needs HPV vaccination, how many doses are required, or when they should be given, the schedule can be determined together with a doctor.