title: Evaluation of immune response to Hepatitis B vaccine in health care workers at a tertiary care hospital in Pakistan: an observational prospective study.
abstract: BACKGROUND
  Seroconversion rates reported after Hepatitis B virus (HBV) vaccination globally ranges from 85-90%. Health care workers (HCWs) are at high risk of acquiring HBV and non responders' rates after HBV vaccination were not reported previously in Pakistani HCWs. Therefore we evaluated immune response to HBV vaccine in HCWs at a tertiary care hospital in Karachi, Pakistan.
  
  
  METHODS
  Descriptive observational study conducted at Aga Khan University from April 2003 to July 2004. Newly HBV vaccinated HCWs were evaluated for immune response by measuring serum Hepatitis B surface antibody (HBsAb) levels, 6 weeks post vaccination.
  
  
  RESULTS
  Initially 666 employees were included in the study. 14 participants were excluded due to incomplete records. 271 (41%) participants were females and 381(59%) were males. Majority of the participants were young (<25-39 years old), regardless of gender. Out of 652 HCWs, 90 (14%) remained seronegative after six weeks of post vaccination. The percentage of non responders increased gradually from 9% in participants of <25, 13% in 25-34, 26% in 35-49, and 63% in >50 years of age. Male non responders were more frequent (18%) than female (8%).
  
  
  CONCLUSIONS
  Seroconversion rate after HBV vaccination in Pakistani HCWs was similar to that reported in western and neighboring population. HCWs with reduced immune response to HBV vaccine in a high disease prevalent population are at great risk. Therefore, it is crucial to check post vaccination HBsAb in all HCWs. This strategy will ensure safety at work by reducing nosocomial transmission and will have a cost effective impact at an individual as well as at national level, which is very much desired in a resource limited country.
authors.affiliation: Department of Pathology and Microbiology (Supariwala building) Aga Khan University Hospital, Karachi, Pakistan. dr.zeeshan@adeels.net
authors.forename: Mohammad
authors.initials: M
authors.lastname: Zeeshan
authors.forename: Kauser
authors.initials: K
authors.lastname: Jabeen
authors.forename: Anita Nausheen Akbar
authors.initials: AN
authors.lastname: Ali
authors.forename: Ailia Wilayat
authors.initials: AW
authors.lastname: Ali
authors.forename: Saadia Z
authors.initials: SZ
authors.lastname: Farooqui
authors.forename: Vikram
authors.initials: V
authors.lastname: Mehraj
authors.forename: Afia
authors.initials: A
authors.lastname: Zafar
mesh_terms: D000328:Adult; D000367:Age Factors; D005260:Female; D006282:Health Personnel; D006509:Hepatitis B / Q000517:prevention & control*; D006510:Hepatitis B Antibodies / Q000097:blood*; D017325:Hepatitis B Vaccines / Q000276:immunology*; D006761:Hospitals; D006801:Humans; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000517:prevention & control*; D010154:Pakistan; D011446:Prospective Studies; D012737:Sex Factors
chemical_list: D006510:Hepatitis B Antibodies; D017325:Hepatitis B Vaccines