Definition

The practice of giving a vaccine to people who did not receive it at the recommended age. Catch-up vaccines may be given to a person who has not been previously vaccinated, who has missed a scheduled vaccine dose, or who has not completed a vaccine series. They may also be given to some people, such as those with a weakened immune system, who might be at high risk of certain types of infection, such as human papillomavirus (HPV) infection.