Low hepatitis B prevalence among pre‐school children in Denmark: Saliva anti‐HBc screening in day care centres

Abstract

Although Denmark has a low hepatitis B virus (HBV) prevalence, HBV transmission has been reported in Danish day-care centres. The aim of this study was to validate saliva anti-HBc testing as a method for HBV screening, the applicability of saliva sampling to pre-school children, and to determine the HBV prevalence in Danish day-care centres with a high proportion of immigrants. For validation, paired saliva and plasma samples were obtained from blood donors and injecting drug users. Employees and children in day-care centres with a high proportion of immigrant children were offered saliva screening followed by blood test if positive. The specificity and sensitivity of anti-HBc tests on saliva was 100% (102 blood donors and four injecting drug users) and 85.9% (61 of 71 anti-HBc-positive injecting drug users), respectively. In all samples from HBsAg (n = 7) or anti-HBc IgM-positives (n = 9), anti-HBc was detected in saliva. Adequate saliva samples were obtained from 93% (588/634) of children and 100% (166/166) of employees participating in the day-care centre survey. Among children 55% were of non-Scandinavian origin and only one (0.2%, 95% CI [0.0; 1.0]) was HBV positive. Among employees the corresponding values were 22% and 7 (4.2%). The positive predictive value of the saliva test was 25% (1/4) among children and 88% (7/8) among adults. In conclusion, saliva testing is feasible for HBV screening among children in low prevalence populations, but any anti-HBc reactivity should be confirmed by plasma analysis. The HBV prevalence in pre-school children in Denmark is low even among immigrants from endemic areas.

Utility of oral fluid samples for hepatitis B antibody detection in real life conditions

“…It is important to note that the oral fluid anti-HBc assay had high sensitivity in individuals presenting active infection compared to those with anti-HBc isolate and past HBV infection. This is in agreement with prior observations of the best HBV assay performance using oral fluid samples from ambulatory settings [31] and among those with active infection with 90.5% sensitivity when only HBV infected individuals were included in the study [9].…”

Hepatitis B virus transmission in pre-adolescent schoolchildren in four multi-ethnic areas of England

“…The study also failed to show evidence of transmission of hepatitis B from immigrant schoolchildren to Danish-born schoolchildren. Another Danish study identified only one child (an immigrant from Somalia) with resolved infection in 585 preschool children where 55 % were immigrants [36]. A study from Australia showed a low prevalence of HBV infection in low-risk schoolchildren irrespective of the proportion of high-risk children in their classes [37].…”

Public Health Dilemmas Concerning a 2-year old Hepatitis-B Carrier – Response

“…Transmission through saliva, though unlikely, is certainly possible, especially where the boy shows a high HBV viremia [1]. The risk of transmission in day care is low, but has been reported and confirmed by genotyping [2][3][4][5][6]. The theoretical routes of transmission are direct through small wounds and, more important, by child bites.…”