Prevalence of chronic hepatitis B virus infection among children in Uzbekistan: Impact of vaccination

Abstract

Background: Uzbekistan, a highly endemic country for hepatitis B virus (HBV), introduced infant vaccination with hepatitis B vaccine (HepB) in 2001. Since 2002, it had ≥90 % reported immunization coverage for ≥3 doses of HepB (HepB3) and the birth dose (HepB-BD). However, the impact of HepB vaccination and the progress towards achieving the regional hepatitis B control and global viral hepatitis B elimination goals had not been assessed. Methods: To determine current HBsAg prevalence among children in Uzbekistan, in 2022, we conducted a nationwide serosurvey among schoolchildren (grades 1–3) using a stratified, multi-stage cluster design. Participants' basic demographics and HepB immunization information were obtained. Blood specimens were tested for HBsAg using a WHO-prequalified rapid test (Bioline HBsAg WB, Abbott Diagnostics). Samples with positive and indeterminate results were tested for HBsAg by ELISA (Murex HBsAg Version3, Diasorine). Weighted proportions and adjusted 95 % confidence intervals (CI) were calculated. Results: Of 4119 children enrolled in 148 schools, blood was collected from 3753 (91.1 %) and immunization data were available for 3833 (93.3 %). National HBsAg prevalence was 0.20 % (adjusted 95 % CI, 0.09 %–0.38 %). Among children with available immunization data, 97.7 % (97.2 %–98.1 %) received ≥3 HepB doses and 94.9 % (94.1 %–95.5 %) received HepB-BD, including timely HepB-BD in 93.7 % (92.9 %–94.5 %). Conclusions: The survey demonstrated that Uzbekistan has met the <0.5 % European regional HBsAg seroprevalence target and has made substantial progress towards meeting the <0.1 % HBsAg seroprevalence target for the elimination of HBV mother to-child transmission (MTCT). Based on these findings and ≥ 90 % HepB-BD and HepB3 coverage, in 2023, Uzbekistan was validated as having achieved the regional hepatitis B control goal. To achieve the elimination of MTCT of HBV, additional interventions, including improving antenatal screening for HBsAg, providing antiviral treatment of eligible HBsAg-positive pregnant women and hepatitis B immunoglobulin to infants born to HBsAg-positive mothers, should be considered.