A compelling cross-disciplinary collaboration between physicists and immunologists has provided new insights into ways to optimize the efficacy of oral vaccines. The research is initially working towards developing an oral hepatitis B vaccine that is safer, cheaper and more easily administered than the current injectable alternative.
Since the development of an effective hepatitis B vaccine in the early 1980s, the prevalence of the condition has rapidly reduced. However, globally almost one million people still die every year from complications related to chronic hepatitis B infections. The current injectable vaccine is not cheap, and requires refrigerated transport and storage.
Scientists have been working on an oral vaccine for several years but the primary challenge has been creating an encapsulated delivery mechanism that can protect the vaccine from the destructive chemicals in our stomach while it travels down into the intestine, a more effective environment for antibody stimulation.
Prior work has established a silica-material, called SBA-15, can effectively encapsulate the hepatitis vaccine. Recent animal studies have found oral administration of the vaccine within SBA-15 can induce immunological responses at least as strong as the injectable vaccine, but these results have not been consistent, and until now the reason for this inconsistency has been unclear.
The new study tapped the skills of a team of Danish physicists from the Niels Bohr Institute. Using a combination of X-ray and neutron tomography the researchers were given novel imaging insights into how the vaccine was behaving inside the SBA-15 encapsulation.
"We have used a technology commonly used in solid state physics to explore how the vaccine behaves within a particular type of encapsulation," explains Heloisa Bordallo, from the Niels Bohr Institute. "This has yielded crucial information that would not otherwise have been achievable. Now we know what makes the vaccine less effective, and how to optimize it. We know exactly how much vaccine should be put in the silica capsule for it to work best in the body and the clinical trials can be better interpreted."
The ultimate goal of the research, alongside the oral hepatitis B vaccine, is to combine six major vaccines into a single oral formulation. Diphtheria, tetanus, whooping cough, polio, Hib and hepatitis B vaccines, all combined within a single ecapsule would allow for incredible advancements in reaching those in developing countries.
"Getting rid of needles being poked into the arms of little children is an advantage in and of itself," explains one of the main authors on the new study, Martin K. Rasmussen. "It also eliminates any need to sterilize needles and possible side effects such as swelling and infection. And, unlike the vaccine in use today, this type of vaccine needn't be refrigerated."
The new study was published in the journal Scientific Reports.
Source: University of Copenhagen
