The time between HPV shots depends on how many doses you need, which is determined by your age when you start the series. Children who begin between ages 9 and 14 get two doses spaced at least 5 months apart. Teens and adults who start at age 15 or older need three doses, given at 0, 1 to 2 months, and 6 months.
Two-Dose Schedule: Ages 9 Through 14
If you or your child starts the HPV vaccine series before turning 15, only two shots are needed. The minimum gap between the first and second dose is 5 months. Most providers schedule the second shot about 6 to 12 months after the first, but anything at or beyond that 5-month minimum counts as a valid dose.
The two-dose schedule works because younger immune systems mount a stronger antibody response. Studies from multiple countries have confirmed that two doses given to this age group produce protection comparable to three doses given to older teens and adults. A large study in India found single-dose efficacy of 95.4%, and a Costa Rican trial tracking participants for 11 years showed no statistically significant difference in protection between one, two, or three doses. The two-dose schedule is more than sufficient for healthy children in this age range.
Three-Dose Schedule: Ages 15 Through 26
Anyone who starts the series at 15 or older follows a three-dose schedule. The standard timing looks like this:
- Dose 1: Your starting date
- Dose 2: 1 to 2 months after the first shot
- Dose 3: 6 months after the first shot
The minimum intervals are slightly tighter than the recommended ones. You need at least 4 weeks between doses 1 and 2, at least 12 weeks between doses 2 and 3, and at least 5 months between doses 1 and 3. If a dose is given sooner than those minimums, it may not count and could need to be repeated.
This three-dose schedule also applies to people with weakened immune systems, regardless of what age they start. If you’re immunocompromised and began the series before age 15, you still need all three doses on the same 0, 1 to 2, and 6 month timeline.
Adults Ages 27 Through 45
HPV vaccination is routinely recommended through age 26. For adults 27 through 45, the vaccine is available but not universally recommended. The reason is straightforward: most sexually active adults have already been exposed to several HPV strains, so the vaccine provides less benefit at this point. Those who do get vaccinated in this age range follow the same three-dose schedule (0, 1 to 2, and 6 months).
The people most likely to benefit from vaccination after 26 are those who haven’t been exposed to all the HPV types the vaccine covers. Having a new sexual partner is the main risk factor for a new HPV infection. Someone in a long-term, mutually monogamous relationship is unlikely to pick up a new strain.
What Happens If You Miss a Dose
If you fall behind schedule, you do not need to restart the series. Pick up where you left off, even if months or years have passed since your last dose. The CDC is clear on this point: an interrupted series is still valid. Your provider will simply give you whichever dose comes next.
There is no maximum interval between doses. A longer gap won’t reduce the effectiveness of the doses you’ve already received. That said, you aren’t fully protected until you complete the series, so finishing sooner is better than waiting. If you started and stopped, call your provider to schedule your remaining shot or shots rather than beginning again from scratch.
Single-Dose Programs in Other Countries
If you’ve seen headlines about a single-dose HPV vaccine, that reflects a real shift in global health policy. As of late 2024, 57 countries have adopted a single-dose HPV schedule based on growing evidence that one shot provides strong, lasting protection. A randomized trial in Kenya found a single dose was 97.5% effective at preventing cancer-causing HPV strains in girls aged 15 to 20 after 18 months of follow-up. The long-term Costa Rican data showed 82.1% efficacy from one dose after 11 years, which was statistically indistinguishable from two or three doses.
The World Health Organization now supports single-dose use for certain vaccine products. In the United States, however, the CDC has not yet adopted a one-dose recommendation. The current U.S. schedule remains two doses for those starting before 15 and three doses for everyone else.
Quick Reference for Dose Timing
- Ages 9 to 14, healthy: 2 doses, at least 5 months apart
- Ages 15 to 26: 3 doses at 0, 1 to 2, and 6 months
- Ages 27 to 45: 3 doses on the same schedule, if vaccination is chosen
- Immunocompromised, any age: 3 doses at 0, 1 to 2, and 6 months