Just six years ago, Tufts scientists set out to achieve a lofty goal: creating a needleless vaccine that would not need to be refrigerated. After numerous trials and tribulations, the team, partially funded by the Bill and Melinda Gates Foundation, has achieved just that.
The group of scientists, doctors and researchers was led by Abraham Sonenshein, professor and Interim Chair of molecular biology and microbiology at the School of Medicine, and Saul Tzipori, professor of microbiology and infectious diseases at the Cummings School of Veterinary Medicine.
Most vaccines must be refrigerated and carefully transported before use, making it difficult to immunize poor, rural areas without proper medical facilities or electricity. By engineering a vaccine that does not need to be cooled, the team is opening doors for better health in remote parts of the world. Creating this substance, however, was no easy task.
Scientists at Tufts' Sackler School of Graduate Biomedical Sciences had to enclose parts of the bacteria that cause tetanus in a heat-resistant bacterial spore of another type. The spore acts as a protective container, allowing the vaccine to still be viable after extreme conditions.
"This spore is very resistant," Tzipori said. "You can sit it on a bench and leave it in extreme heat."
To test the vaccine's resistance to temperature, researchers submerged the substance in an 80 F water bath for 17 months, Tzipori said. At the end of the experiment, the vaccine was found to still be viable.
Yet the team had another objective: devising a needleless delivery system.
"The second aim of the Bill and Melinda Gates Foundation was to develop a vaccine that does not need to be injected into the body," Tzipori said. "Kids hate getting pricked by needles, and it's expensive to get syringes sterilized."
After failing initially at creating an oral vaccine, the scientists decided to try making nasal drops. These drops were given to mice in three doses, just as the tetanus shot is administered in humans. The experiment was a success, as the mice were found to be protected when immunized with the new construct. Next, the team tried a delivery system that is arguably even easier — drops that are put under the tongue. Once again, the scientists were met with success.
"Putting drugs under the tongue is a very useful way to get things absorbed into the body very rapidly," Tzipori said. "It worked just as beautifully as intranasal."
Experiments were then conducted with pigs, which also proved fruitful. If that was not enough, the scientists were also able to create a rotavirus vaccine in an almost identical manner. Both were found to be successful when administered as drops under the tongue to mice and pigs. Throughout the process, the team was dedicated to creating something that could be realistically used and marked an improvement from what existed already.
"Whatever we were going to make, we wanted to make sure it would be as good as what is used today," Tzipori said.
The team is currently looking to work with commercial companies or government agencies for more funding and to actually create doses of the vaccines for human use, according to Tzipori. If the vaccines are eventually implemented, it could mean significant change in the way communities are immunized — although it's hard to pinpoint exactly what will happen.
"It's hard to predict what effect it will ultimately have, because there are so many competing interests among pharmaceutical companies," Tzipori said.
Not only could third-world countries be immunized more easily and at a lower cost, it is possible the new vaccine could affect the "Vaccine War," named for serious opposition against routine childhood vaccination, largely in the United States and Great Britain. Some believe that certain aspects of vaccines cause disorders in young children, specifically autism. But given the lack of supporting evidence for these theories, this sort of reasoning is frequently dubbed as pseudoscience.
One of the largest problems with the opposition to vaccines is that as fewer people are immunized, the chance of disease outbreak is higher. Many of those who are opposed to vaccines exhibit the "herd mentality," believing that as long as most of the population is immunized they will remain safe from disease. While this is true to some extent, if too many people adopt this thinking, disease outbreak could become a real threat.
"Some people have this idea that ‘If everyone else is immune I don't need to get the vaccine,'" senior Becca Hornthal, who is studying child development and community health, said.
The newly developed vaccines may convince more individuals to immunize themselves and their children. Those afraid of needles would no longer have to worry about getting a round of routine shots. More importantly, certain chemicals or preservatives found in vaccines administered by needle are not present in the Tufts-created vaccine. Since some believe that these chemicals are linked to autism, the needleless vaccine may better persuade supporters of the "Vaccine War" to immunize their children.
"I think it would take a lot of stigma away from going to the doctor and make it something people could better grasp and understand," Hornthal said.
Yet, much of the opposition to vaccines is traced to a desire to explain what is currently unexplainable, like childhood autism.
"There's a real yearning to have an explanation, to blame it on someone," Amy Wallace, a freelance writer who wrote a cover story on the topic for Wired Magazine, said. "And I think that feeling is pretty strong, so the delivery method doesn't really matter."
Although lack of chemicals or preservatives could ease the concern in some people, the "Vaccine War" exists for a number of complex reasons.
"The lack of preservatives would at least help counter the people who worry about preservatives," Wallace said. "However, I think that the opposition to vaccines, the people who fear them, actually fear the actual injection of disease."
Regardless of its effects in America, the vaccines created by Tufts scientists — if they are developed — will mean huge strides for community health in humans and animals all over the world. Only time will tell exactly how and where the new discoveries will be used.
"It's cheap and easy," Tzipori said. "Really, there are a lot of applications of it."
