The incidence of Kawasaki disease after vaccination within the UK pre-school National Immunisation Programme: an observational THIN database study.

PURPOSE: To provide expected incidence rates of Kawasaki disease after vaccination in routine clinical practice and as recommended within a pre-school National Immunisation Programme (NIP). METHODS: A post-immunisation risk period when Kawasaki disease onset might be associated with vaccination was defined as 28 days. Immunisation records for children under 6 years were identified from The Health Improvement Network (THIN) database of electronic UK primary health care records (2008-2012) and linked to previously validated cases of Kawasaki disease with an assigned date of onset. Kawasaki disease incidence in the risk period after a complete NIP recommended set of vaccinations was estimated for five vaccination stages individually and in total. RESULTS: A total of 642 170 complete pre-school immunisation stages from 275 986 children were included. Six cases of Kawasaki disease had onset in the risk period after any NIP stage providing an incidence of 12.8 per 100 000 person years (95%CI 5.7, 28.4). The incidence after any single immunisation stage ranged from 0 to 27.4 (95%CI 8.8, 84.8) per 100 000 person years. CONCLUSION: There were few cases of Kawasaki disease in the risk period after any NIP vaccination combination. The incidence rates will aid in the interpretation of clinical trials and post-marketing surveillance of new vaccines. Copyright © 2016 John Wiley & Sons, Ltd.

Kawasaki disease incidence in children and adolescents: an observational study in primary care.

BACKGROUND: Kawasaki disease is reported to be increasing in incidence and is the commonest childhood cause of acquired heart disease in the Western world. AIM: To determine the current UK incidence of Kawasaki disease across childhood and adolescence; and investigate trends over time and season. DESIGN AND SETTING: An observational, descriptive study in the UK. METHOD: The Health Improvement Network (THIN) database of primary healthcare records was searched for codes or text indicating Kawasaki disease. Identified records were compared with a study case definition and a date of onset was assigned to cases. The incidence, age/sex distribution, and trend in seasonal and temporal distribution were estimated (2008-2012). RESULTS: A total of 110 episodes of Kawasaki disease in 109 children were identified from 3.9 million person-years observation. The incidence of Kawasaki disease was 2.8 per 100 000 person-years (95% confidence interval [CI] = 2.3 to 3.4) when aged <20 years; 9.1 (95% CI = 7.3 to 11.2) aged <5 years, and 3.0 per 100 000 (95% CI = 2.0 to 4.3) across the age groups when possible cases were included. More cases were identified in males (55%) with one-fifth of cases diagnosed after 5 years of age. There was no statistically significant trend in incidence over the study years (P = 0.10 adjusted for sex and month), or between seasons (P = 0.65 adjusted for year and sex). CONCLUSION: Although the incidence of Kawasaki disease remains low and has stabilised in the UK, GPs should recognise that the condition occurs throughout childhood and across the seasons.