Hepatitis B virus, a double-stranded DNA virus, is the causative factor for both acute and chronic hepatitis B (HepB) infections. According to the Hepatitis B Foundation, close to 300 million people worldwide are living with hepatitis B infections.6 Fortunately, hepatitis B infection is preventable via HepB vaccination.
In the early 1980s, the US Food and Drug Administration (FDA) approved the first hepatitis B vaccine developed using hepatitis B surface antigen (HBsAg) derived from the blood plasma of hepatitis B carriers. The antigen particles were inactivated and purified using chemical and physical means consisting of formaldehyde, pepsin, and urea, followed by heat treatment. This blood-derived hepatitis B vaccine had very high safety records but a new platform using noncarrier blood-derived substance was underway out of concern over transmission of potential bloodborne pathogens.
In the mid-1980s, the FDA approved a recombinant DNA-based hepatitis B vaccine. Specifically, the steps are:
- Hepatitis B surface antigen (HBsAg) is extracted from hepatitis B viral participles.
- The HBsAg gene is inserted into yeast cells for multiplication to yield ample quantities.
- The expressed HBsAg gene product, in the form of polypeptides, assembles into a three-dimensional protein that mimics the naturally occurring HBsAg particles but lacks the capacity for infectivity.
- The HBsAg is next absorbed onto an adjuvant called aluminum hydroxide, Al(OH)3, intended to boost the immunogenicity of this second-generation hepatitis B vaccine.
Besides the availability of hepatitis B-only vaccines, a combination vaccine, TWINRIX, also exists. It is active against both hepatitis B and hepatitis A.7
The Centers for Disease Control and Prevention (CDC) recommends a hepatitis B vaccine to help protect vaccinated individuals against liver cancer. A large-scale multiple-year, 40,000 subjects with 37 years of follow-up study has reported that the hepatitis B vaccine yielded 70% efficacy in protection against deaths resistant from liver cancer, 64% efficacy in liver cancer death prevention, and 72% efficacy in prevention of liver cancer relapse.8
6. Cao M, Fan J, Lu L, et al. Long term outcome of prevention of liver cancer by hepatitis B vaccine: Results from an RCT with 37 years. Introduction section. Cancer Lett. 2022;536:215652. doi:10.1016/j.canlet.2022.2156527. GSK Group of Companies. "TwinRix." Twinrix.ca website. 2022. http://www.twinrix.ca/en-ca/q-and-a.html8. Cao M, Fan J, Lu L, et al. Long term outcome of prevention of liver cancer by hepatitis B vaccine: Results from an RCT with 37 years. Conclusions section. Cancer Lett. 2022;536:215652. doi:10.1016/j.canlet.2022.215652
