Comparative analysis of disease severity between genotypes IA and IIIA of hepatitis A virus

Although hepatitis A is a major health problem worldwide, it has not yet been clarified whether or not viral factors affect the clinical characteristics. This study aimed to investigate if a genotype of hepatitis A virus (HAV) affects disease severity among adolescent and adult populations. Clinical data and specimens were collected from patients ≥16-years-of-age with acute hepatitis A at two university hospitals in Korea during the two study periods: 1998 and 1999 (n=45), and 2009 (n=66). Nucleotide sequencing of the complete VP1 region of the HAV isolates was performed for phylogenetic analysis and genotyping. Clinical parameters related to disease severity were compared by HAV genotype to determine its clinical relevance. Of the 87 patients, 47 were male and the mean age was 29.8±8.1 years. The genotype IIIA (93.0%, 53/57) was predominant in the year 2009, whereas IA (93.3%, 28/30) was the major genotype in 1998 and 1999. When comparing disease severity between the two HAV genotypes, the patients with genotype IIIA were older and had higher alanine aminotransferase (ALT) levels, prolonged prothrombin times and lower serum albumin levels. In a multivariate logistic regression model, higher ALT levels≥1,000IU/L (odds ratio [OR] 11.7, 95% confidence interval [CI] 2.5-54.0) and longer hospitalization (OR 22.49, 95%CI 4.6-132.5) were associated independently with genotype IIIA. In conclusion, this study indicates that HAV genotype might be one of the viral factors responsible for the disease severity of hepatitis A.