An Oral Vaccine for Hepatitis B: Challenges, Setbacks, and Breakthroughs

Despite the commercialization of a highly effective injectable vaccine for over 20 years, the hepatitis B virus (HBV) continues to be a significant health concern worldwide. An estimated 240 million people are chronically infected with the virus despite efforts by the World Health Organization (WHO) to implement child vaccination programs in all WHO member countries for over 10 years. Plants hold the promise of bringing us one step closer to eradication of the disease by providing a low-cost, heat stable, oral alternative to the parenteral vaccine. Several technical hurdles have been overcome over the last several years and a maize-based vaccine has emerged as the front-runner oral vaccine candidate. This review outlines those technical hurdles in the context of hepatitis B epidemiology and socioeconomic factors influencing adoption of vaccination compliance. Additional hurdles to commercialization, such as regulatory considerations and production, are also discussed.