A breakthrough by researchers at McMaster University could save lives around the world by making it easier and far cheaper to deliver fragile vaccines for deadly viruses such as Ebola and influenza to remote communities in developing countries.
The innovation is almost as easy “as stirring milk and sugar into coffee,” said Matthew Miller, an assistant professor in McMaster’s biochemistry department, who was part of the interdisciplinary team that worked on the project. The process involves combining sugars used for other purposes with the drugs, turning the temperature-sensitive vaccine into a lightweight sugary gel that can travel for long periods through harsh climates.
Globally, nearly 20 million children are vulnerable to preventable diseases because they don’t get vaccines, with one-quarter living in three countries: Afghanistan, Nigeria and Pakistan.
Transporting and storing vaccines is complicated because they need to be kept at low temperatures to remain viable – a system of constant refrigeration known as the “cold chain.” Warm weather and rough roads don’t just increase the risk the vaccines will fail, they also raise the price tag – in some cases, transportation alone accounts for 80 per cent of the cost of a vaccine program, Dr. Miller said.
Solar-powered, mini-refrigerators that can travel on the back of camels or wagons, have been one solution, says Vincent Leung, a chemical engineer at McMaster and the lead author of the paper published today in the journal Scientific Reports. But these are expensive and heavy, the units break down and they can only carry so much of the vaccine.
At McMaster, a team of engineers and infectious-diseases scientists decided to look for a lighter, more travel-friendly solution. They had one already: an edible coating that had been previously created by chemical engineers at the university to extend the shelf life of fruit.
As researchers discovered, the same two ingredients – a pair of sugars called trehalose and pullulan, which are used to make the jelly coating on breath strips – could do the same for a delicate vaccine. Combine, stir and dry, and their work suggests that a vaccine would be able to travel safely and relatively cheaply in the sugary gel, protected from the heat for months.
“It is extremely simple,” said Dr. Miller, using the coffee milk-and-sugar analogy. The process, he said, can be easily adopted by any facility that can manufacture vaccines. Upon arrival at the destination, saline water would be added to restore the vaccine to a liquid state so that it can be administered.
To make sure they were on the right track, the team at McMaster tested their theory with two of the hardest vaccines to transport, one for the herpes virus, and another for influenza A. “This was the extreme end of testing,” Dr. Miller said. “Now that we know it works there, it can be employed with any vaccine.” For instance, he said, it could work with the Ebola vaccine created by a lab in Winnipeg, which is difficult to transport to hot spots in remote parts of Africa. Being able to transport vaccines more easily will also help eradicate “smouldering fires” of preventable illnesses such as polio in regions that are difficult to reach.
The team received funding from the Bill and Melinda Gates Foundation, which has been investing in science that can improve vaccines and their delivery. The researchers are now looking for an industry partner to conduct a clinical trial, so the process can be approved for use in the field.
“This isn’t just interesting science,” said Dr. Leung, who worked on the project as part of his doctoral degree. “This is science that can change the world.” Not a bad birthday present for Dr. Leung, who turns 33 on the same day he will see his work published.
Erin Anderssen