Adverse events after school leavers received combined tetanus and low dose diphtheria vaccine

Since October 1994, children in the United Kingdom have been offered tetanus vaccine combined with a low dose of diphtheria vaccine (Td) at the age of 15 to 18 years. It is recommended that schoolchildren who have already received a booster of tetanus vaccine at the time of an injury should be given low dose diphtheria vaccine alone. When this vaccine is not available, however, it is recommended that Td vaccine should be given to all children. This study was performed to compare the frequency of adverse events after Td vaccine in 15 year old children with and without a history of an additional tetanus booster in the preceding 10 years. Two hundred and sixty-five children were followed up-52 pupils (20%) with a history of an additional tetanus booster, 157 (59%) with no such history, and 56 (21%) whose history was unclear. Mild local reactions were common and occurred more commonly in children with a history of an additional tetanus booster. Twenty-three pupils (44%) who had received an additional tetanus booster had swelling over 2 cm diameter at the injection site, compared with only 39 (25%) of those with no such history (p < 0.013). Systemic symptoms were equally unusual in both groups. Only three children experienced symptoms attributed to vaccine that were severe enough for them to miss school or attend a doctor; and none of these had received an additional tetanus booster. We conclude that, in the absence of a supply of low dose diphtheria vaccine, offering Td vaccine to children with a history of additional tetanus booster is an acceptable policy.