preserve vaccines without refrigeration

The normal way we all know vaccines are being preserved especially the live vaccines is by subjecting them to cold-chains(refrigeration).

Most available vaccines today owes its efficacy to this cold-chain and can be significantly hampered if they are not stored in a temperature range of 2–8 °C most of the time.

This necessity places a tremendous financial and logistical burden on vaccination programs, particularly in the developing world. The development of thermally stable vaccines can greatly alleviate this problem and, in turn, increase vaccine accessibility worldwide.

But that tradition will soon be changing as a team of Canadian scientists at McMaster University have developed a simple and inexpensive method to preserve vaccines without refrigeration.

This latest discovery will revolutionize the public-health game in parts of the world where epidemics are raging and resources for medical interventions are limited.

The chemical engineers, spearheaded by a recent PhD graduate Vince Leung and supervised by professor Carlos Filipe, combined herpes and influenza A vaccines with a sugar solution and dried the mixture into a thin film — these vaccines were chosen because they’re among the most fragile vaccines out there and so sensitive to heat.

They stored this at a desert-like 40 degrees Celsius for weeks before reconstituting it in saline solution and testing it in mice.

The vaccines were as safe and as effective as they would have been “fresh out of the fridge,” Filipe said. The flu vaccine was still good after three months, and the herpes after two.

This research was published in the journal Scientific Reports on Tuesday

The team also carried out the test on a pneumonia vaccine and an experimental Ebola vaccine using the same process. They all passed the test too.

According to Filipe, the idea for the project was planted a few years ago, when one of the paper’s authors, Sana Jahanshahi-Anbuhi — then a grad student, now an assistant professor at Concordia University.

She she was staring at the dissolvable Listerine breath strips and had a flash of insight: The strips are thin sheets of film made of a sugar called pullulan. Scientists already knew sugars can help protect the integrity of some fragile biological molecules, such as enzymes. What if they swapped the Listerine ingredients for something else — like a protein or virus from a vaccine? Could the pullulan sugars protect those too?

It turns out that when a vaccine is used, the pullulan helps form a barrier around the vaccine molecules that keeps oxygen out and it also holds them in place, keeping them from unfolding and breaking up when exposed to heat.

A second sugar, trehalose, helped protect the vaccine particles from drying out too much as the mixture was dried into a film.

The next steps to this project will be to test out more vaccines and also investigate deeply on the safety and efficacy in humans, not just mice.

Filipe’s team of scientist has just applied to the Gates Foundation for funding, and will be in touch with medical and other partners within a year to talk about how to bring the product to market.

To get the project to pass through regulatory hurdles, Filipe expects the process to be relatively smooth, partly because the sugars used are already approved by Health Canada and the U.S. Food and Drug Administration, and the process uses existing vaccines with well-established safety and efficacy.

The concern in medicine has always been that existing vaccines are extremely fragile. Many need to be stored in a very cold freezer, and can only be held at fridge temperature (2 to 8 C) for a few days, during which the countdown begins to get the medicine to the end user.

Any screw-ups or delays along the way will break the cold chain, rendering the medicine useless and vulnerable people unprotected, especially in rural, remote, and conflict-affected areas.

This simplified process discovered will be of help because a film could be dropped into a vial of saline, shaken for five seconds, and then injected, could help save lives and money.

It has been tested with the vaccine against measles, which is back with a vengeance worldwide, is an especially urgent priority.

Among the many measle outbreaks going on, according to the WHO the worst are in Madagascar, where 84,765 people were infected between October 2018 and March 2019. Then, Ukraine with 56,094 infected, and India has 19,544.


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