Marshall, H.Clarke, M.Heath, C.Quinn, H.Richmond, P.Crawford, N.Elliott, E.Toi, C.Kynaston, A.Booy, R.Macartney, K.2019-05-072019-05-072019Journal of Infectious Diseases, 2019; 219(3):391-3990022-18991537-6613http://hdl.handle.net/2440/118836Background: This national, sentinel prospective study aimed to identify children with severe hospitalized varicella, despite availability of universal 1-dose vaccination since 2005, and determine associations between virus genotypes and disease severity. Methods: Children with varicella or zoster from 5 Paediatric Active Enhanced Disease Surveillance hospitals were enrolled. Lesions were swabbed for genotyping. Associations with disease severity were analyzed using multiple regression. Results: From 2007 to 2015, 327 children with confirmed varicella (n = 238) or zoster (n = 89) were enrolled. Two hundred three (62%) were immunocompetent children; including 5 of 8 children who required intensive care unit management. Eighteen percent (36 of 203) of immunocompetent children had been previously vaccinated. Vaccinated children aged >18 months were less likely to have severe disease (9%; 5 of 56) than unvaccinated children (21%; 21 of 100; P = .05). Three of 126 children who had virus genotyping (2 immunocompromised) had varicella (n = 2) or zoster (n = 2) due to the Oka/vaccine strain. European origin clades predominated and were independently associated with more severe disease (odds ratio = 3.2; 95% confidence interval, 1.1– 9.5; P = .04). Conclusions: Severe hospitalized varicella still occurs with a 1-dose varicella program, although predominantly in unvaccinated children. Most 1-dose vaccine recipients were protected against severe disease. Viral genotyping in complex hospitalized cases is important to assist in monitoring disease due to Oka-vaccine strain.en© The Author(s) 2018. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.Children; herpes zoster; varicella; immunizationJournal article003009949210.1093/infdis/jiy5180004625984000082-s2.0-85058574320437165Marshall, H. [0000-0003-2521-5166]Clarke, M. [0000-0001-9635-8784]