The HPV Vaccine: Who Should Get It, When, and Why
Cervical cancer is one of the few cancers we can largely prevent, and the HPV vaccine is the single most effective step. This guide explains who benefits, the right age to vaccinate, how many doses are needed, and why vaccination still goes hand in hand with screening.
Medically reviewed by Dr. Priyadatt Patel, MBBS, MS (Obstetrics & Gynaecology) — Senior Gynecologist · Advanced Laparoscopic Surgeon · IVF and Endometriosis Programme Lead, Balaji Horizon Women’s Hospital, Ahmedabad. · Last reviewed: 30 June 2026.
Almost all cervical cancer is caused by persistent infection with the human papillomavirus (HPV) — and that single fact is the reason cervical cancer is, in principle, preventable. The World Health Organization has set a goal to eliminate cervical cancer as a public-health problem, built on three pillars: vaccinate girls against HPV, screen women, and treat early disease. The vaccine is the foundation of that strategy. This guide answers the practical questions families ask us, who should be vaccinated, at what age, how many doses, and whether vaccination removes the need for screening. For the other half of prevention, see our guide to cervical cancer screening, and for the wider context our gynaecological oncology overview within our gynaecology services.
What HPV is and why it matters
HPV is an extremely common virus passed through skin-to-skin and sexual contact; most sexually active people encounter it at some point, and in the majority the immune system clears it without harm. The problem is persistent infection with certain “high-risk” types, particularly HPV 16 and 18, which together cause about 70% of cervical cancers. Over years, persistent high-risk HPV can drive the cell changes that, if undetected, may progress to cancer of the cervix. The same virus is also responsible for most cancers of the vulva, vagina, anus and throat, and for genital warts. The vaccine teaches the immune system to recognise and neutralise these viral types before they can establish a lasting infection.
Why the vaccine works best before exposure
The HPV vaccine is preventive, not therapeutic, it stops new infection but does not treat an HPV infection already present. This is why timing is everything. The vaccine gives its strongest protection when it is given before any exposure to the virus, which in practice means before the start of sexual activity. That is the single most important principle in this whole subject: the earlier the vaccine is given within the recommended window, the more complete the protection.
Who should get the HPV vaccine, and at what age?
The primary target group, recommended by the WHO and by health authorities worldwide, is girls aged 9 to 14 years — old enough to mount a strong immune response, and almost always before exposure. Vaccination is also worthwhile for older adolescents and young adults who were not vaccinated in time:
- Girls 9–14 years — the ideal window; the routine recommendation.
- 15–20 years — recommended; catch-up vaccination is clearly beneficial.
- Young women into the mid-20s — still worthwhile, as not everyone has been exposed to every vaccine type.
- Older adults (roughly 27–45) — may be considered after an individual discussion; the benefit is smaller because some exposure is likely to have occurred, so the decision is made case by case.
- Boys and young men — also benefit (protection against genital warts and several HPV-related cancers), and gender-neutral vaccination helps reduce transmission overall.
- People with weakened immunity (including those living with HIV) — vaccination is recommended, with a fuller dose schedule.
How many doses are needed?
The number of doses depends mainly on age at the first dose and on the immune status of the person. Current WHO guidance supports a simplified schedule:
| Age / group at first dose | Typical schedule |
|---|---|
| Girls 9–14 years | One or two doses (a single-dose schedule is now WHO-endorsed; where two are used, given several months apart) |
| 15–20 years | One or two doses, depending on the programme followed |
| 21 years and older | Typically a two-dose schedule |
| Immunocompromised / living with HIV | A fuller (usually three-dose) schedule is advised |
Schedules are kept under review and can vary slightly between countries, so the exact plan for you or your child is best confirmed at consultation. The important message is reassuring: for the youngest, most important group, protection can now be achieved with very few doses.
How effective and how safe is it?
The HPV vaccine is one of the most studied vaccines in use. In populations where girls were vaccinated young and at scale, rates of the high-grade pre-cancerous cervical changes the vaccine targets, and, increasingly, of invasive cervical cancer itself, have fallen substantially. On safety, the vaccine has an excellent record across hundreds of millions of doses; the common side effects are the expected ones of any injection, a sore arm, sometimes a brief fever or feeling faint, and serious reactions are rare. It does not affect future fertility.
If I am vaccinated, do I still need cervical screening?
Yes, and this is the point most often misunderstood. The vaccine protects against the most important high-risk HPV types, but not against every oncogenic type, so a small residual risk remains. Vaccination and screening are partners, not alternatives: the vaccine prevents most infections, and screening catches the small number of changes that still occur, while they are still easily treatable. A vaccinated woman should continue cervical screening on the normal schedule for her age. Our cervical screening guide explains the HPV test and Pap smear, and when each is done.
What if I am older or already sexually active?
Being past the ideal age, or already sexually active, does not automatically rule out vaccination, it simply means the conversation becomes more individual. Because some exposure may already have occurred, the average benefit is smaller than for a young adolescent, but it is rarely zero: few people have been exposed to all the types the vaccine covers. For women into their twenties, vaccination is generally still worthwhile; between roughly 27 and 45 it becomes a considered, individual decision. The honest framing we use is that the vaccine is most valuable early, valuable through young adulthood, and a reasonable personal choice thereafter, never a guarantee, but a meaningful reduction in risk.
HPV vaccine and screening: the two arms of prevention
It helps to picture cervical cancer prevention as a single strategy with two arms. The first arm, vaccination, removes most of the risk before it can begin, and is most powerful when given young. The second arm, screening, finds and treats the small number of changes that still slip through, long before they become dangerous. A girl vaccinated at 12 and screened appropriately as an adult has, between those two simple steps, almost the entire protective benefit modern medicine can offer against this disease. That is a genuinely hopeful message, and it is why we encourage families to act on the vaccine in good time.
Frequently asked questions
At what age should the HPV vaccine be given?
The ideal age is 9 to 14 years, before any exposure to the virus, which is when protection is strongest. Catch-up vaccination is recommended through the teens and is still worthwhile into the early-to-mid twenties. Between roughly 27 and 45 it becomes an individual decision made after discussion, because some exposure may already have occurred.
How many doses of the HPV vaccine are needed?
It depends on age and immune status. For girls aged 9 to 14, WHO now endorses a one- or two-dose schedule, and a single dose can give strong protection. People who start at 21 or older usually have two doses, and those who are immunocompromised or living with HIV are advised to have a fuller, usually three-dose, schedule. The exact plan is confirmed at consultation.
If I have had the HPV vaccine, do I still need cervical screening?
Yes. The vaccine protects against the most important high-risk HPV types but not every one, so a small residual risk remains. Vaccination and screening work together, the vaccine prevents most infections and screening catches the few changes that still occur, while they are easily treatable. Continue cervical screening on the normal schedule for your age.
Is the HPV vaccine safe, and does it affect fertility?
The HPV vaccine has an excellent safety record across hundreds of millions of doses. Side effects are usually mild and short-lived, a sore arm, sometimes a brief fever or feeling faint. Serious reactions are rare, and the vaccine does not affect future fertility.
Can boys and men have the HPV vaccine?
Yes. Boys and young men benefit from protection against genital warts and several HPV-related cancers, and vaccinating both sexes reduces transmission in the community. Many countries now run gender-neutral HPV vaccination programmes for this reason.
References
- World Health Organization. Human papillomavirus (HPV) and cervical cancer — fact sheet and cervical cancer elimination initiative. 2024.
- World Health Organization. Updated recommendations on HPV vaccination schedule (single- and two-dose schedules). 2022, with subsequent product confirmations 2024.
- World Health Organization. Global strategy to accelerate the elimination of cervical cancer as a public health problem (90–70–90 targets). 2020.
This article is for general education and does not replace personalised medical advice. The right vaccination plan depends on age, health and individual circumstances, and should be decided with a qualified doctor. If you have questions about the HPV vaccine for yourself or your child, please consult a specialist.
