Hepatitis B Virus Genotypes Identified in Alaska

Brian J. McMahon, MD

Genotype F has emerged as the common hepatitis B virus (HBV) genotype amongst chronic HBV patients living in Alaska.

A team, led by Brian J. McMahon, MD, Liver Disease and Hepatitis Program, Alaska Native Tribal Health Consortium, assessed HBV genotype on hepatocellular carcinoma (HCC) occurrence in patients living in Alaska with chronic hepatitis B infections where there are currently A2, B6, C2, D, and F1 HBV genotypes.

There is currently not much known on HBV genotype and its role in the outcomes for patients with chronic HBV infections.

The Study

In the study, the researchers examined 1185 Alaskan natives with a median follow-up of 35.1 years. The overall HBV genotype distribution was 49% D, 18% F, 13% A, 6% C, 3% B, 0.1% H, and 12% undetermined.

The researchers calculated the incidence of HCC per 1000 person-years of follow-up to identify which groups by age, sex, and genotype met current American Association for the American Association for the Study of Liver Diseases (AASLD) HCC surveillance criteria.

The team compared the risk of HCC by genotype, age, sec, and Alaskan region using Poisson regression and the incidence of HCC was calculated using the sex specific AASLD cutoff recommended for the Asian population of 50 years for women and 40 years for men.

Each patient underwent HCC screening semi-annually, which was derived using alpha-fetoprotein levels and abdominal ultrasounds.

HCC Cases

Overall, there were 63 cases of HCC identified, with incidence for genotype F being the highest at 5.73 per 1000 person-years of follow-up.

The next most common genotype was genotype C at 4.77 per 1000-person years of follow-up.

A at 1.28 per 1000-person years, genotype D at 0.47 per 1000-person years and genotype B at 0.00 per 1000-person years of follow-up.

The risk of HCC was high for genotypes F (RR, 12.7; 95% CI; 6.1-26.4), C (RR, 10.6; 95% CI, 4.3-26.0), and A (RR, 2.9; 95% CI, 1.0-8.0) compared to genotypes B or D.

Genotype F was also the highest in certain demographics, including men younger than 40 and females younger than 50, with an incidence of 4.79 per 1000-person years.

“HBV genotype was strongly associated with HCC HBV genotype should be considered in risk factor stratification,” the authors wrote.

HBV Vaccination

Earlier this year, researchers identified various risk factors that yield lower responses to immunizations and negative outcomes for (HBV) infections, including diabetes mellitus, older age, and obesity, leading to a need to enhance immunogenicity of HBV vaccines for adults with these risk factors.

In data presented during the American Diabetes Association’s (ADA) 81th Scientific Sessions, a team, led by Francisco Diaz-Mitoma, MD, PhD, VBI Vaccines, compared the immunogenicity and safety of 3-doses of 3-antigen / 3A-HBV (Sci-B-Vac) and 1-antigen / 1A-HBV (Engerix-B) HBV vaccines administered at months 0, 1, and 6.

The non-response rates rose for patients with the identified risk factors of diabetes, older age, and obesity.

The study, “Hepatitis B Virus (HBV) Genotype: A Significant Risk Factor in Determining which Patients with Chronic HBV Infection should Undergo Surveillance for Hepatocellular Carcinoma: The Hepatitis B Alaska (HEP-B-AK) Study,” was published online in Hepatology.