As United States President Donald Trump learned on live TV this week, you can’t speed up the development of a vaccine simply by bullying scientists in public. Any coronavirus vaccine must be tested and tested and then tested again.
One of his advisers admonished him: “You don’t want to rush and treat a million people and find out you’re making 900 000 of them worse.” As advice goes this is almost as wise as the well-known proverb, “Don’t contradict a moody head of state in public if you enjoy not being thrown into a nearby dungeon.”
Nevertheless, speed does become important once a vaccine exists for Covid-19 or any other virus. A vaccine only stays viable for a certain period before it expires, so getting it where it needs to go is a race against the clock.
According to researchers writing in the journal Science Advances this week, using a thin-film membrane for oral administration means that a vaccine could be distributed far more quickly, widely and cheaply —and remain viable for longer — than vials of injectable liquid.
And, in their paper, the researchers from the University of Austin in Texas describe how thin-film platforms can even allow vaccines to be safely stored for as long as three years — at room temperature.
The World Health Organisation (WHO) estimates that nearly 50% of freeze-dried and 25% of liquid vaccines produced worldwide are destroyed because of disruptions in the cold chain of supply logistics, “which entails transporting, storing and monitoring them at a recommended temperature from the point of production to the point of use”.
Even without those losses, it’s an extremely expensive enterprise. So much so that, in their paper, lead author Irnela Bajrovic and her colleagues make particular mention that the cost of distributing and administering vaccines often far outweighs the cost of making them.
According to a simulation model published in the journal Vaccine in 2015, it would cost $64-billion to introduce 18 vaccines to 94 countries within 10 years. Of that total cost, $38-billion would have to be spent on distribution and administration alone.
Much of this goes to the cooling systems required for transportation. But the cost of transporting the sheer volume of the liquid vaccines is considerable. According to the WHO’s estimates, a batch of 350 000 single doses of liquid, injectable vaccines weighs nearly three tonnes — and that’s without the syringes.
Bajrovic and her colleagues believe the benefits of a thin-film platform would essentially render these cost and weight issues meaningless. Vaccines that retain their efficacy over extended periods at room temperature mean that refrigeration is no longer the same concern. And according to the researcher’s calculations, 350 000 single doses of vaccine in a film-membrane format can be loaded into a box weighing just 3kg.
So long, syringe
Any vaccine contained in a film would have to be developed specifically for mucosal absorption so that it could be administered orally —you would literally pop it into your mouth like a sweet. As the authors note, this delivery method is “needle free, eliminating the need for and associated costs of trained personnel for vaccine administration”.
Together, these cost and weight savings mean that once a vaccine is developed it could be distributed further and more quickly than any current supply chains can support — by orders of magnitude.
As Bajrovic et al point out, distribution and administration obstacles mean that each year tens of millions of infants around the world do not receive the basic immunisations routinely used in high-income or metropolitan areas. Shifting to thin-film delivery suddenly puts these areas in reach, with the potential to save many millions of people.
Possibly even the disagreeable chap in the dungeon.