These recommendations are based on government policy as discussed in Immunisation against infectious disease (the 'Green Book'), published by the Department of Health (DH) [DH, 2006d; DH, 2008a]. These guidelines are derived from the best current evidence encompassing immunological, epidemiological, and controlled studies.

• The diseases prevented by vaccines used in the Childhood Immunization Programme cause (or have caused in the past) extensive morbidity and mortality. In most cases, the incidence of these diseases has been greatly reduced by use of vaccines, and in some cases diseases have been virtually eradicated in the UK.
• The quality of evidence to support the use of vaccines depends largely on when the vaccine was introduced. The efficacy of vaccine components that have been in use for decades, for instance, is usually evident by the marked fall in incidence of the disease it protects against compared with the period prior to the vaccine's introduction. Newer vaccines are more likely to have evidence from controlled trials to support their effectiveness and safety. For further information, see individual diseases in Supporting evidence.
• Booster doses are necessary for most diseases to ensure an adequate antibody response and protection throughout childhood and into adulthood.
• All girls and young women up to 18 years of age will be offered HPV vaccination to protect against the future risk of cervical cancer, either as part of an ongoing immunization programme or as part of a catch-up campaign. The objective is to provide three doses of HPV vaccine to females before they reach an age when the risk of HPV infection increases and they are at subsequent risk of cervical cancer [DH, 2008b; DH, 2008c; MHRA, 2010]. It is estimated that:
• Up to 70% of cases of cervical cancer might be avoided.
• Four hundred lives a year may be saved.