Nano Vaccine For Hepatitis B Shows Promise For Third World
Nanoemulsion Could Save More Lives By Removing Current Vaccines’ Drawbacks
Chronic hepatitis B infects 400 million people worldwide, many of them children. Even with three effective vaccines available, hepatitis B remains a stubborn, unrelenting health problem, especially in Africa and other developing areas. The disease and its complications cause an estimated 1 million deaths globally each year.
In many poor countries, refrigerated conditions required for the current vaccines are costly and hard to come by. It’s often difficult in the field to keep needles and syringes sterile. The need to have people return for the three shots currently required also limits success.
Now, a new vaccine that avoids these drawbacks has moved a step closer to human trials. Health researchers hope it will make it possible to immunize large numbers of children and adults in Africa, Asia and South America efficiently and safely.
Scientists at the Michigan Nanotechnology Institute for Medicine and Biological Sciences at the University of Michigan report that a novel, needle-less method for getting an immunity-stimulating agent into the body has proved non-toxic and able to produce strong, sustained immune responses in animal studies. The vaccine is based on a super-fine emulsion of oil, water and surfactants placed in the nose.
The research was supported by the Grand Challenges in Global Health initiative, which is funded by the Bill & Melinda Gates Foundation, the Foundation for the National Institutes of Health, the Wellcome Trust and the Canadian Institutes of Health Research. The findings appear online in the journal PLoS ONE.
The nanoemulsion represents a new delivery method for an antigen already used in existing hepatitis B vaccines to activate the body’s immune defenses.
“Our results indicate that needle-free nasal immunization, using a combination of nanoemulsion and hepatitis B antigen, could be a safe and effective hepatitis B vaccine, and also provide an alternative booster method for existing vaccines,” says James R. Baker, Jr., M.D., the study’s senior author and director of the institute. He also is Ruth Dow Doan Professor and allergy division chief in the U-M Department of Internal Medicine.
The nanoemulsion is made up of soybean oil, alcohol, water and detergents emulsified into droplets less than 400 nanometers in diameter.
The study suggests that the new type of hepatitis B vaccine will not have rigid cold storage requirements and could require fewer administrations than current vaccines, which require three shots given over a period of six months. Protective immunity with the new vaccine required only two immunizations in animals. The vaccine also avoids the risk of spreading needle-borne infections.
The nanoemulsion vaccine also avoids the temporary pain and redness that results after people get shots with the current vaccines, in which an irritating compound, alum, is used as an adjuvant, or enhancer of a vaccine’s effect. There was no local inflammation at the nasal site of administration with the new vaccine.