title: Mother-to-infant transmission of hepatitis B virus infection: significance of maternal viral load and strategies for intervention.
abstract: OBJECTIVE
  Immunoprophylaxis reduces but does not completely eradicate hepatitis B virus (HBV) transmission. This prospective study aims at assessing the rate and risk factors of maternally transmitted HBV infection.
  
  
  METHODS
  We enrolled 303 mother-infant pairs with positive maternal hepatitis B surface antigen (HBsAg) under current immunization program. Maternal viral load was determined by a real-time PCR-based assay. The children were tested for HBsAg at 4-8 months and/or 1-3 years of age. Rates of HBV infection were estimated using a multivariate logistic regression model.
  
  
  RESULTS
  HBeAg-positive mothers (81/303, 26.7%) had higher viral loads than HBeAg-negative mothers (7.4 ± 1.9 vs. 2.7 ± 1.4 log10 copies/ml, p<0.0001). Ten children, born to HBeAg-positive mothers with high viral load (median, 8.4; range, 6.5-9.5 log₁₀ copies/ml), were chronically infected. After adjustment for maternal age, birth type, factors related to maternal-fetal hemorrhage, gestational age, infant gender, birth weight, timeliness of vaccination, and feeding practice, maternal viral load was significantly associated with risk of infection (adjusted odds ratio for each log₁₀ copy/ml increase, 3.49; 95% confidence interval (CI), 1.63-7.48; p=0.001). The predictive rates of infection at maternal viral load levels of 7, 8, and 9 log₁₀ copies/ml were 6.6% (95% CI, 0.5-12.6%; p=0.033), 14.6% (95% CI, 5.6-23.6%; p=0.001), and 27.7% (95% CI, 13.1-42.4%; p<0.001), respectively.
  
  
  CONCLUSIONS
  Additional strategies to further reduce transmission should be considered in mothers with a viral load above 7-8 log₁₀ copies/ml.
authors.affiliation: Department of Pediatrics, Cardinal Tien Hospital, New Taipei City, Taiwan.
authors.forename: Wan-Hsin
authors.initials: WH
authors.lastname: Wen
authors.forename: Mei-Hwei
authors.initials: MH
authors.lastname: Chang
authors.forename: Lu-Lu
authors.initials: LL
authors.lastname: Zhao
authors.forename: Yen-Hsuan
authors.initials: YH
authors.lastname: Ni
authors.forename: Hong-Yuan
authors.initials: HY
authors.lastname: Hsu
authors.forename: Jia-Feng
authors.initials: JF
authors.lastname: Wu
authors.forename: Pei-Jer
authors.initials: PJ
authors.lastname: Chen
authors.forename: Ding-Shinn
authors.initials: DS
authors.lastname: Chen
authors.forename: Huey-Ling
authors.initials: HL
authors.lastname: Chen
mesh_terms: D000328:Adult; D002675:Child, Preschool; D005260:Female; D006513:Hepatitis B e Antigens / Q000097:blood; D019694:Hepatitis B, Chronic / Q000150:complications* / Q000635:transmission* / Q000821:virology; D006801:Humans; D007116:Immunization, Passive; D007136:Immunoglobulins / Q000627:therapeutic use; D007223:Infant; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical / Q000517:prevention & control; D008297:Male; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000821:virology*; D011446:Prospective Studies; D012307:Risk Factors; D019562:Viral Load; D055815:Young Adult
chemical_list: D006513:Hepatitis B e Antigens; D007136:Immunoglobulins; C045213:hepatitis B hyperimmune globulin