title: Hepatitis B Seroprotection and the Response to a Challenging Dose among Vaccinated Children in Red Sea Governorate.
abstract: OBJECTIVE
  To assess the long-term effectiveness of hepatitis B virus vaccine and the need for a booster dose among children who received three doses of vaccine during infancy in Red Sea Governorate.
  
  
  METHODS
  A cross-sectional study was performed. Interviews with children (9 months to 16 years) and parents were done. Blood samples to assess Hepatitis B markers were tested. Children showing no seroprotection received a booster dose to assess their anamnestic response after four weeks and one year later.
  
  
  RESULTS
  None of the participants had evidence of chronic Hepatitis B. The seroprotection rate was 23.3% and it significantly decreased with age. Multivariate logistic analysis revealed that older age was the significant predicting variable for having no seroprotective level, while baseline anti-HBs level < 3.3 IU/L was the predicting variable for not developing early anamnestic response or loss of late anamnestic response.
  
  
  CONCLUSIONS
  Long-term immunity persists among children who received complete series of hepatitis B vaccination during infancy even in absence or reduction of anti-HBs over time. Therefore, a booster dose is not necessary to maintain immunity till the age of sixteen.
authors.affiliation: National Research Center, Child Health, Cairo, Egypt.
authors.forename: Samia M
authors.initials: SM
authors.lastname: Sami
authors.affiliation: National Research Center, Community Medicine Research, Cairo, Egypt.
authors.forename: Iman I
authors.initials: II
authors.lastname: Salama
authors.affiliation: National Research Center, Community Medicine Research, Cairo, Egypt.
authors.forename: Ghada A
authors.initials: GA
authors.lastname: Abdel-Latif
authors.affiliation: National Research Center, Community Medicine Research, Cairo, Egypt.
authors.forename: Lobna A
authors.initials: LA
authors.lastname: El Etreby
authors.affiliation: National Research Center, Community Medicine Research, Cairo, Egypt.
authors.forename: Ahmed I
authors.initials: AI
authors.lastname: Metwally
authors.affiliation: Faculty of Medicine, Al Azhar University - Microbiology and Immunology, Cairo, Egypt.
authors.forename: Naglaa F
authors.initials: NF
authors.lastname: Abd El Haliem
keywords: Anamnestic response; Booster dose; Children; Egypt; HBV vaccine; Seroprotection