Cytomegalovirus, Epstein-Barr virus and varicella zoster virus infection in the first two years of life: a cohort study in Bradford, UK.

BACKGROUND: Cytomegalovirus (CMV), Epstein Barr virus (EBV) and varicella-zoster virus (VZV) are common herpesviruses frequently acquired in childhood, which establish persistent, latent infection and are likely to impact the developing immune system. Little is known about the epidemiology of CMV and EBV infections in contemporary UK paediatric populations, particularly whether age at infection differs by ethnic group. METHODS: Children enrolled in the Born in Bradford Allergy and Infection Study had a blood sample taken and a questionnaire completed at 12 and 24 months of age. Ordered logistic regression quantified associations between ethnicity and other risk factors and age at CMV/EBV/VZV infection (<12 months, 12-24 months, uninfected at 24 months). RESULTS: Pakistani children (n = 472) were more likely to be infected with CMV and EBV at a younger age than White British children (n = 391) (CMV: adjusted odds ratio (OR) 2.53, 95% confidence interval (CI) 1.47-4.33; EBV: adjusted OR 2.16, 95% CI 1.43-3.26). Conversely, Pakistani children had lower odds of being VZV infected in the second year than White British children (adjusted OR 0.57, 95% CI 0.33-0.97). There was a strong association between increasing birth order and later CMV infection in Pakistani children. CONCLUSIONS: We report large differences in CMV and EBV incidence in the first 2 years between Pakistani and White British children born in Bradford, which cannot be explained by differences in risk factors for infection. Our data will inform the optimum schedule for future CMV and EBV vaccination programmes.