why should they be kept cold?

In the race for the vaccine against Sars-CoV-2, one of the challenges will be its conservation. A simple refrigerator? An overpowered freezer? And besides, why do vaccines like the cold so much?

The battle is raging between the major pharmaceutical companies engaged in the production of the future vaccine against the Sars-CoV-2 virus, responsible for Covid-19.

In addition to the announced efficacy rate (90% for the vaccine developed by Pfizer, 94.5% for that of Moderna), one of the other issues concerns its conservation.

Pfizer’s vaccine would indeed require storage at -70 ° C, which no “conventional” freezer allows.

Theoretical advantage therefore for Moderna: a simple refrigerator could be sufficient to keep the vaccine cold. But why is cold so important for vaccine storage?

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Fragile and sensitive

First and foremost because “vaccines are fragile biological products,” recalls the World Health Organization. “Vaccines lose some of their activity or efficacy, that is, their ability to adequately protect the vaccinated subject, when exposed to inappropriate temperatures. This drop in vaccine efficacy is irreversible ”.

Vaccines are therefore particularly sensitive to extreme conditions. While some react badly to light, the vast majority, like the flu, prefer the cold.

“As soon as you return from the pharmacy, your vaccine must be placed in the fridge, for its conservation, between + 2 ° C and + 8 ° C”, indicates the site of Public Health France, vaccination-info-service.fr.

The vaccine should be stored inside the refrigerator but not in the door, where the temperature is higher and varies depending on the openings and closings. Everything the vaccine hates! Unless otherwise specified, it should not be frozen either.

What if my vaccine has been stored in poor conditions, or if it has expired?

“Like any medication, vaccines should not be thrown away in the sewer or with household garbage,” says vaccination-info-service.fr. It should be brought back to your pharmacist.

A noter

To respond to the challenge of massive vaccination campaigns in areas of the world where cold storage is problematic, teams of researchers are testing alternatives.

Like those scientists from the University of Bath (UK), who encapsulated active proteins from the tetanus vaccine in silica shells.

According to these researchers, after exposure to high heat or to ambient air for three years, the vaccine, tested on mice, would not have lost any of its properties.

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