A new study has shown that a nasal hepatitis B vaccine elicits a dramatic immune response in animals without requiring three vaccinations, sterile syringes, or refrigeration—three factors that impede the delivery of current hepatitis B vaccines.
In the study, a single dose of the nasal vaccine triggered a protective response in animals roughly 450 times greater than that elicited by currently approved human vaccines. The animal studies demonstrate a magnitude of immunity that has not been seen in advanced preclinical testing of other nasal vaccines, according to the scientists at the University of Michigan and NanoBio Corporation.
Moreover, the mucosal vaccine produced three distinct types of immunity—mucosal, cellular, and systemic—which enabled a rapid immune response that could kill virus-infected cells and prevent future infections. Traditional injected vaccines do not elicit mucosal or cellular immunity.
The study has critical implications for developing countries where hepatitis B presents a serious health threat, said James R. Baker Jr., M.D. (pictured), lead author on the paper.
Developing nations have difficulty providing proper refrigeration, sterile needles, or three separate vaccinations, as are currently required. As a result of these challenges and despite the existence of effective vaccines, more than 400 million children and adults worldwide are infected, and more than a million people die from hepatitis B each year.
“We have developed a new vaccine that is extremely safe, easy to administer, and which rapidly builds protection against hepatitis B infection,” said Baker. “The same vaccine platform has also been shown to elicit significant immune responses in animal studies with influenza, anthrax, smallpox, RSV, and HIV. Plans are under way to begin testing in humans.”
The vaccine platform and its associated research, funded in part by the Bill & Melinda Gates Foundation, represents a major departure from traditional vaccines on numerous levels.
Among its unique qualities, the mucosal vaccines are delivered directly to the lining of the nose where immune cells recognize the foreign antigen contained in the vaccine. This rapid stimulation of the immune system does not involve inflammatory chemicals as used in injected vaccines, which can cause pain and swelling at the site of vaccination. It also produces cellular immunity that is not seen with intramuscular vaccination.
“Patients who lack cellular immunity can build up the needed antibodies to eradicate viral particles in the blood and interstitial fluid, but they may not be able to remove infected cells where the virus hides,” said Baker. “This is often the case with chronically infected patients, so our vaccine may be of particular benefit to this population of immune-compromised individuals.”
Robust immunity aside, the mucosal vaccine also eliminates a number of logistical impediments that have stymied traditional vaccine use worldwide:
- The nanoemulsion vaccine is safe and simple to produce, containing a mixture of oil, water, alcohol, and two surfactants together with commercially available antigens
- The nanoemulsion itself serves as the “adjuvant” to stimulate an immune response, demonstrating significant antigen-sparing properties
- The formulation is extremely stable, allowing for long-term storage of 3 to 6 weeks or longer with potentially no refrigeration
- Finally, a single-dose administration schedule enables rapid immunity against hepatitis B, whereas traditional injected vaccines usually require as many as three separate vaccinations over 6 months
Illustration: University of Michigan Health System.
NanoBio Corporation Press Release (08/13/08)
Medical News Today (08/14/08)
Abstract (Public Library of Science ONE; (3)8 (08/13/08))