Fig. 1 Amino acid substitutions within HBsAg and the overlapping regions of reverse transcriptase from patients with concurrent HBsAg and anti-HBs. The part within the “a” determinant is underlined. Reference sequences of genotype C are obtained from the NCBI website ( http://www.ncbi.nlm.nih.gov/projects/genotyping/genotype  C: X046151). A short line demonstrates there is no mutation in this locus, and “stop” represents the stop codon.