Vaccines, here comes a transparent "candy" to melt in your mouth

Gianluca Riccio


The first challenge is to find a vaccine. The second is to distribute it well, quickly, economically, widely. A film that melts in your mouth can make a difference.

She ran around the world to identify an effective coronavirus vaccine (here the latest developments). The next challenge will be to produce it and distribute it quickly worldwide.

A research team led by Mary Croyle, Professor of Pharmaceuticals at the University of Texas has developed a new method to stabilize live viruses and other biological medicines. The vaccines are embedded in a rapidly dissolving transparent film, a sort of "candy" that does not require refrigeration and can be administered orally.

The ingredients for making vaccine film (a transparent disk resembling a wafer) are cheap and the process is relatively simple, it could make vaccination campaigns much quicker. Large quantities of the device can be shipped and distributed easily given its space-saving shape.

This new technology recently published in the journal Science Advances, has the potential to dramatically improve global access to vaccines and other biologic medicines.

Inspired by candy

Film vaccines
Credits: Maria Croyle

Dr. Croyle's team began developing this technology in 2007, when the National Institutes of Health asked to develop a stable, needle-free method of administration for a vaccine.

The idea to develop a film was inspired by a documentary about how the DNA of insects and other living things can be preserved for millions of years in amber.

It was a simple idea, but no one had tried it. The researchers began work by mixing a variety of formulations containing natural ingredients such as sugars and salts and testing them for their ability to form a sort of flat “vaccine candy.”

Initially, many of the preparations tested killed the organism as the film formed or crystallized, destroying the virus or bacteria that were intended to form the basis for a vaccine.

As many as 450 attempts later, the team found a formulation that could suspend viruses and bacteria in a transparent film to be dissolved in the mouth.

Oral vaccine on transparent film

Film vaccines
The composition of a “vaccination host”

The researchers' subsequent work simplified the process to the point that in-depth technical training would not be required to carry it out. Dosages and ingredients allow for very rapid distribution: a few hours from production to shipment.

The advantages of this system

All stored vaccines lose their potency over time. The speed with which they do it depends mainly on the temperature at which they are maintained. Keeping vaccines continuously refrigerated is difficult and expensive – and in some parts of the world, nearly impossible.

This is why creating vaccines on film, which can be stored and transported at room temperature is a huge advantage.

The development of the new type of distribution is also the result of a fortuitous discovery. Working on an Ebola vaccine, Maria Croyle's team studied films containing the virus over three years old. They rehydrated them for study purposes and found that over 95% of the viruses in the film were still active. Obtaining this type of shelf life for an unrefrigerated vaccine has been surprising.

Ecological footprint

The ecological footprint left by global immunization campaigns is never considered. The 2004 Philippine measles elimination campaign immunized 18 million children in one month. The "collateral" effect on an ecological level? 19,5 million syringes, 143 tons of sharps waste and almost 80 tons of non-hazardous waste. Empty vials, syringe wrappers, caps, cotton swabs and packaging. The implications for a broader campaign would be even more significant.

Croyle's technology, by contrast, can be distributed by healthcare workers equipped with only a sachet. Once taken, this vaccine “candy” will leave no trace, except (hopefully) for a healthy global population.

Croyle aims to bring the vaccine film to the market as soon as possible. It is appropriate to say that it would make a difference.

To report research, discoveries and inventions, contact the editorial team!

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