Chronic Hepatitis B Infection
Hepatitis B is a disease of the liver caused by the hepatitis B virus (“HBV”), characterized by hepatic (e.g. liver) inflammation, injury, and even cell death. The disease can present acutely, and resolve on its own, or can progress to a chronic state.
There are more than two billion individuals with serological evidence of HBV infection worldwide. Of these, 240 million are chronic carriers and approximately 780,000 hepatitis B-related deaths occur annually. Despite advances in antiviral therapy, only a minority of patients with chronic hepatitis B will have a sustained immune response to treatment. Therefore, primary prevention by vaccination is considered the ideal way to control HBV.
First- and Second-Generation Hepatitis B Vaccines
Hepatitis B vaccine failure is often explained by certain conditions such as smoking and obesity, and by comorbidities such as advanced age, renal failure, diabetes, and other immunosuppression. Genetically determined resistance may also play a factor in non-responsiveness.
Sci-B-Vac®: A Third-Generation Hepatitis B Vaccine
In contrast to second-generation hepatitis B vaccines, Sci-B-Vac® contains not only the S antigen from the hepatitis B virus, but also two additional surface antigens, the pre-S1 and pre-S2 surface antigens. By mimicking all three surface antigens of the hepatitis B virus, Sci-B-Vac® may provide more opportunities for the immune system to respond with antibodies to the virus, helping it to overcome some limitations of prior hepatitis B vaccines, which present only the S antigen.
Moreover, anti-HBV antibody concentrations were found to be higher in a large percentage of vaccinated individuals and an immune response could be elicited by Sci-B-Vac® using a lower dosage than second-generation hepatitis B vaccines.
Researchers have also sought to understand how Sci-B-Vac® may benefit persons that are less likely to respond to currently marketed second-generation vaccines, including:
- Elderly Persons: The immune system becomes less effective as individuals age. Aging is associated with increased susceptibility to infectious diseases, reduced response to vaccination, and an increased risk of developing severe or complicated illnesses as a result of infection. The impaired response to vaccination is due to accumulating functional defects at multiple levels of the immune system, which lower the overall magnitude and quantity of response to vaccination. Although safe, there is an age-specific decline in immune responsiveness to some currently marketed hepatitis B vaccines starting around age 40.
- Persons with End-Stage Renal Disease: Chronic kidney disease is a condition where the kidneys are damaged and cannot filter blood as well as healthy kidneys. This lack of filtration leads to excess waste buildup in the body that can cause other health problems. Without treatment, diseased kidneys may stop working after a time, a condition called kidney failure or end-stage renal disease (“ESRD”). Currently marketed hepatitis B vaccine options may provide limited seroprotection to persons with ESRD.
- Persons with Diabetes: Diabetes is a condition in which a person has a chronically high blood sugar level, due to an inability to absorb sugar and use it as energy. High blood sugar levels can lead to a number of complications including kidney failure, blindness, nerve damage, cardiovascular disease, and non-traumatic amputation. Persons with diabetes are less responsive to hepatitis B vaccines than healthy adults.
In addition, because of their contact with patients and/or infectious materials, many healthcare workers are at an increased risk of being exposed to HBV. The U.S. Advisory Committee on Immunization Practices (“ACIP”) recommends that all healthcare workers at risk of acquiring or transmitting HBV be vaccinated. Compared to some currently marketed hepatitis B vaccines, Sci-B-Vac® may offer faster seroprotection, potentially reducing the risk of infection.
To learn more about Sci-B-Vac®, visit: https://www.vbivaccines.com/sci-b-vac/