Vaccine safety is a contentious issue, and parental concern continues.1 An online survey (Harris Poll) in 2004 showed that half of parents are concerned that a child might develop a long term medical condition as a result of vaccination, and 10% are “uncomfortable” having their child vaccinated owing to “health reasons.”2 These parental concerns may be fuelled by the increasing number of websites making serious allegations about vaccine safety.3

Independent bodies—for example, the US Institute of Medicine—have reviewed the evidence for several vaccines and have generally found them to be safe, albeit with rare risks such as anaphylaxis.4 However, local reactions to vaccines are common—ranging from 6% to 50%, depending on the vaccine, definition of local reaction, and dose number in a series—and this can contribute to the safety concerns expressed by parents. Local reactions can be reduced either by using less reactogenic vaccines, such as …