Hospitalisations for Varicella Among Children and Adolescents in a Tertiary Referral Hospital in Hong Kong, 2004 to 2008

Objective: To describe the epidemiology of varicella-associated morbidities in paediatric patients hospitalised at a tertiary referral hospital in Hong Kong from 2004 to 2008. Methods: The hospital discharge database and medical records of Princess Margaret Hospital were retrospectively analysed for admissions associated with varicella from 2004 to 2008. Patients aged less than 18 years were included in the study. Results: During the study period, 598 children (328 males, 270 females) were hospitalised for varicella or its complications. The mean age on admission was 57.6 months (range 1-204 months) and the mean duration of hospitalisation was 3.7 days (range 1-27 days). The overall complication rate was 47%. Skin and soft tissue infections were the most common complication (43.1%), followed by surgical scarlet fever (35.2%), neurological complications (18.1%) and pneumonia (8.2%). Compared to immunocompetent children, immunocompromised children were more likely to be older (p <0.001) and hospitalised for longer periods (p<0.001), but had a lower complication rate (13.8% vs 48.7%) as a result of institution of specific antiviral therapy (p<0.001). Five patients required intensive care and two of them were immunocompromised. There was no mortality. Conclusion: Varicella can lead to serious complications and prolonged hospitalisation, even in previously healthy children. This study provides important information on the local epidemiology of children hospitalised for varicella in the era following the introduction of varicella vaccine.