Depending on the vaccine, some (but not all) immunisations must be repeated. For example, children who have received both of their MMR injections are likely to benefit from protection against measles, mumps and rubella for life.
However, with polio, diphtheria, tetanus, or whooping cough, experts say the initial immunisation lasts for between five and 10 years. The protection provided by the influenza vaccine is even shorter. This is because flu viruses may change from season to season, meaning that all vaccine-eligible individuals – including the more vulnerable older people, for example – must get a new vaccine every year. Boosters can be described as a ‘reminder’ to your immune system.
For more information, see ‘Vaccination – 20 Objections & Responses’, produced by the Robert Koch Institute and Paul Ehrlich Institute