Following five years of collaboration, researchers from the Cummings School of Veterinary Medicine, Tufts University School of Medicine, Boston University and Tulane University have created a new vaccine for rotavirus, which causes severe diarrhea.
Their findings, released in last month's issue of Clinical and Vaccine Immunology, showed that the vaccine effectively produced immune response and protection from a rotavirus infection when tested on mice, results which lead the way for the research team to now test the vaccine on humans.
Rotavirus is responsible for the death of up to 500,000 children each year in the developing world.
Abraham Sonenshein, the principle investigator for the project and a professor of molecular biology at the School of Medicine, said that diarrhea caused by rotavirus is treatable in hospitals in the United States but in less advanced countries, treatment is limited by a lack of resources.
"Children in the developing world don't have access to the medical services that we have here," he said. "The whole vaccine project [is] designed to solve problems in the developing world."
Sonenshein began the vaccine project 15 years ago in collaboration with Jerry Keusch, an international health professor at Boston University, but was forced to abandon it for a number of years due to lack of funding, he said.
In 2004, the Bill and Melinda Gates Foundation gave the project a grant as part of a contest seeking solutions to problems in the developing world, he said. With this new source of funding, Sonenshein was able to assemble a team to continue the research.
The new vaccine has a number of features that make it ideal for distribution in developing countries, Sonenshein said. Of particular importance, he said, is that the vaccine is not heat sensitive.
"The biggest issue for vaccines for children [is] lack of refrigeration," Sonenshein said, adding that this problem is often referred to as "the cold chain." The new vaccine mitigates this problem with the use of spore-forming bacteria, according to Kathy Kerstein, a member of the research team from the School of Medicine.
"The advantage of spores is that they are heat-resistant and chemical-resistant," Kerstein said.
This serves to make the vaccine very heat stable, according to Sonenshein. Sangun Lee, a Cummings research associate for the project and the first author of the study, added that the researchers had successfully tested storing the vaccine at room temperature and above.
The next step will be to test the vaccine in humans, a process that could last more than five years, according to Sonenshein. Once the vaccine has been proven safe and effective, the researchers would need to find a partner to manufacture and distribute it throughout the developing world, Sonenshein said.
The vaccine is administered through nose drops and eliminates the use of needles, a method that the researchers hope will make it safer and easier to administer.
"Intranasal inoculation is a coming thing in vaccines," Sonenshein said.
Lee explained that it would have been possible to administer the vaccine through any mucus membrane, such as the eyes or anus. The team tried to create an oral vaccine, but because the oral version did not produce the desired effect in mice, the team ultimately settled on the nose.
Many vaccines require a process called protein purification, whereby proteins from a harmful virus or bacteria are extracted and purified for use in the inoculation, a process that can prove expensive and complex, Sonenshein said. The new rotavirus vaccine, however, uses harmless bacteria that have been engineered to display rotavirus proteins, making the purification process unnecessary.
The bacteria are so inexpensive to grow that the vaccine could cost as little as pennies per dose, according to Sonenshein.
Sonenshein believes that the spore-forming bacteria that the research team employed could be used as the vehicle for many other vaccines. The team hopes to develop new heat-resistant varieties of the four major vaccines currently given to children in first world countries, including those for tetanus and pertussis, commonly known as whooping cough, according to Sonenshein.
"There is no reason to think that this bacterial platform would not be suitable for any kind of vaccine," Sonenshein said.
Still, the rotavirus vaccine has only been tested in animals, so any vaccine for a different disease would have to go through a series of tests before it could be proven safe and effective, he said.
