Does someone ever need more than one injection of the HPV vaccine?

The number of injections somebody needs depends on their age and how well their immune system works:

• people under 25 usually have 1 injection
• people aged 25 to 45 usually have 2 injections (given between 6 months and 2 years apart)
• people with a weakened immune system have 3 injections (given over a 12-month period)