title: Isolated hepatitis B core antibody positive among vaccinated cohort in Malaysia.
abstract: OBJECTIVE
  Hepatitis B core antibodies (anti-HBc) are detected in almost every patient with previous exposure to hepatitis B virus (HBV). However, with this marker alone, one cannot understand the activity of the disease; therefore, this study aimed to identify the implication of isolated hepatitis B core antibody and evaluate the effect of hepatitis B vaccine booster in isolated anti-HBc among adults who received the HBV vaccine as infants.
  
  
  METHODS
  A prospective cohort study of vaccinated undergraduate students of University Putra Malaysia.
  
  
  METHODS
  A total of 408 undergraduate students who received infant hepatitis B vaccination volunteered for this study; 5 mL of venous blood was taken from the volunteers. Hepatitis B surface antigen (HBsAg) and core antibodies were tested using a commercially available enzyme-linked immunosorbent assay kit according to the manufacturer's instructions (DRG international Inc., USA). Molecular detection of hepatitis B viral DNA was performed using nested polymerase chain reaction.
  
  
  RESULTS
  The prevalence of isolated anti-HBc among the vaccinated cohort was found to be 5.0%, out of which 80% had a hepatitis B surface antibodies (anti-HBs) titer higher than 10 IU/L, while 20% had less than 10 IU/L anti-HBs titer. All the anti-HBc positivesubjects had detectable hepatitis B viral DNA in their serum. Anamnestic response was found to be 100% among isolated anti-HBc with negative antibody.
  
  
  CONCLUSIONS
  Isolated anti-HBc developed protective levels of anti-HBs after a single dose of recombinant hepatitis B vaccination. HBV DNA was detected in all isolated anti-HBc indicating occult chronic HBV infection with undetectable HBsAg.
authors.forename: Shuaibu Abdullahi
authors.initials: SA
authors.lastname: Hudu
authors.forename: Yasmin A
authors.initials: YA
authors.lastname: Malik
authors.forename: Mohd Taib
authors.initials: MT
authors.lastname: Niazlin
authors.forename: Nabil Saad
authors.initials: NS
authors.lastname: Harmal
authors.forename: Ahmed Subeh
authors.initials: AS
authors.lastname: Alshrari
authors.affiliation: Prof. Zamberi Sekawi, Medical Microbiology and Parasitology,, Faculty of Medicine and Health Sciences,, Universiti Putra Malaysia,, B-7-1, Kyvilla Apartment,, Jalan 5/5 Serdang Perdana, Selangor 43300, Malaysia, T: 60166225698, zamberi@upm.edu.my.
authors.forename: Zamberi
authors.initials: Z
authors.lastname: Sekawi
mesh_terms: D015331:Cohort Studies; D004279:DNA, Viral / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006510:Hepatitis B Antibodies / Q000097:blood*; D006514:Hepatitis B Surface Antigens / Q000276:immunology*; D017325:Hepatitis B Vaccines / Q000008:administration & dosage* / Q000276:immunology; D019694:Hepatitis B, Chronic / Q000175:diagnosis / Q000276:immunology; D006801:Humans; D007117:Immunization, Secondary; D008296:Malaysia; D008297:Male; D016133:Polymerase Chain Reaction; D011446:Prospective Studies; D013334:Students; D014495:Universities
chemical_list: D004279:DNA, Viral; D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines