Or anti-HBcAg were tested for HBsAg and HBV DNA. Postchallenge specimens were tested for anti-HBsAg only. A response towards the challenge dose was defined as a postchallenge anti-HBsAg degree of 10 IU/liter amongst persons with aReceived 21 November 2012 Returned for modification 17 January 2013 Accepted 4 February 2013 Published ahead of print 13 February 2013 Address correspondence to Philip R. Spradling, [email protected]. Copyright ?2013, American Society for Microbiology. All Rights Reserved. doi:10.1128/CVI.00694-MATERIALS AND METHODSStudy participants. The prevalence of HBsAg in American Samoa was 7 in 1985. Because of this, the territory initiated a program of universal hepatitisApril 2013 Volume 20 NumberClinical and Vaccine Immunologyp. 559 ?cvi.asm.orgSpradling et al.TABLE 1 Responses to a hepatitis B vaccine challenge dose of college students having a reported historya of hepatitis B vaccination for the duration of infancyNo. ( ) with postchallenge anti-HBsAg titer (IU/liter) of: 0 12 (9) 12 (17) 0 1? 34 (26) 24 (33) ten (17) ten 84 (65) 36 (50)b 48 (83) GMC (IU/liter) 7.1c 99.TABLE 2 Subanalysis of responses to a hepatitis B vaccine challenge dose of 42 students with documented receipt of hepatitis B vaccine at birth ( 7 days of age) and a total of 3 doses completed by 12 months of ageNo. ( ) with postchallenge anti-HBsAg titer (IU/liter) of: 0 three (7) 3 (13) 0 1? 14 (33) ten (42) 4 (22) ten 25 (60) 11 (46)a 14 (78) GMC (IU/liter) 9.3b 92.Baseline anti-HBsAg titer (IU/liter) (n) ten (130) 0 (72) 1? (58)a bBaseline anti-HBsAg titer (IU/liter) (n) 10 (42) 0 (24) 1? (18)a bEither written documentation or verbal report by student was accepted. P 0.001, chi-square or Fisher precise test. c P 0.001, t test.P P0.025, chi-square or Fisher exact test. 0.01, t test.baseline anti-HBsAg degree of 10 IU/liter. The results of serologic testing were not offered for the investigators or participants till soon after completion on the study. Statistical analysis. To examine hepatitis B immunity, we determined the proportion of participants with serologic proof of hepatitis B immunity and HBV infection. Amongst students with baseline anti-HBsAg level of 10 IU/liter, we compared the proportion of people who responded towards the challenge dose with an anti-HBsAg degree of 0 IU/liter versus these with levels of 1 to 9 IU/liter at the baseline.6299-85-0 In stock Information were analyzed with PASW Statistics 18 (SPSS, Inc.Xantphos Pd G2 Chemical name , Somers, NY).PMID:23460641 The chi-square test and Fisher precise test had been utilized to evaluate categorical variables, as suitable. Geometric imply concentrations (GMCs) of anti-HBsAg had been calculated, along with the t test was utilised to compare differences among GMCs. Students with no detectable anti-HBsAg have been assigned a value of 0.05 IU/liter for calculation of GMCs.RESULTSStudy population. Of 213 students who volunteered to participate, 212 have been enrolled and completed a questionnaire, underwent baseline blood operate, and received a challenge dose of hepatitis B vaccine. Only 2 (0.9 ) of your 212 have been constructive for anti-HBcAg, and both were damaging for HBsAg and HBV DNA. On the 212 students enrolled, 153 (72 ) returned 2 weeks later for the follow-up anti-HBsAg test. The median age of those 153 students was 20.two years (25 to 75 interquartile range, 19.two to 22.three), 60 were female, the median body mass index was 33.eight kg/m2 (25 to 75 interquartile range, 25.2 to 35.1), 60 reported getting sexually active, and 1 had a loved ones history of hepatitis B (nonmaternal). The demographic and vaccination history of students w.