title: Seroconversion of hepatitis B vaccine in infants related to the mother's serostatus in a community of São José dos Campos, state of São Paulo, Brazil.
abstract: OBJECTIVE
  To detect seroconversion of hepatitis B vaccine and antibody waning 3 years after vaccination in children immunized according to the World Health Organization schedule and its relationship to the mother's serostatus during pregnancy.
  
  
  METHODS
  A serological study was carried out in São José dos Campos. Blood samples from pregnant women were taken for hepatitis B marker serology. To evaluate seroconversion in infants born to these women, serology was performed 1 month after they were vaccinated with recombinant vaccine. Another group of children was evaluated 3 years after being immunized.
  
  
  RESULTS
  Among 224 pregnant women, 0.9% were positive for hepatitis B surface antigen, 8.0% for antibodies to the surface antigen, and 4.5% for antibodies to the virus core. Seroconversion among 174 infants was as follows: absent in 18 children (10.35%), low level in 15 (8.62%), intermediate level in 26 (14.94%), and a high level (good response) in 115 (66.09%). Antibody positivity after 3 years was as follows: absent in 8 children (7.92%), low level in 51 (50.5%), intermediate level in 20 (19.8%), and high level in 22 (21.78%). Considering the age that the vaccine was administered, a significant proportion of non-seroconverters was found among children who had received the complete 3-dose schedule before 9 months (P = 0.023). Another factor that significantly contributed to the lack of seroconversion was the presence of any serological marker for hepatitis B during pregnancy (P = 0.044).
  
  
  CONCLUSIONS
  Data gathered in this work show that the immunization schedule for hepatitis B in low or moderate prevalence areas should be revised in order to optimize seroconversion.
authors.affiliation: Basic Health Unit of Campo dos Alemães, São José dos Campos, SP, Brazil.
authors.forename: Tereza Monteiro
authors.initials: TM
authors.lastname: Ribeiro
authors.forename: Raymundo Soares
authors.initials: RS
authors.lastname: Azevedo
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000367:Age Factors; D001938:Brazil; D016009:Chi-Square Distribution; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006510:Hepatitis B Antibodies / Q000097:blood; D006514:Hepatitis B Surface Antigens / Q000097:blood / Q000276:immunology; D017325:Hepatitis B Vaccines / Q000097:blood / Q000276:immunology*; D006801:Humans; D007112:Immunity, Maternally-Acquired / Q000276:immunology; D017589:Immunization Programs / Q000592:standards*; D007115:Immunization Schedule; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009035:Mothers; D011247:Pregnancy; D037841:Pregnant People; D016036:Seroepidemiologic Studies; D013997:Time Factors
chemical_list: D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines