While the demand for the anti-Covid vaccine is very strong, the objective of the health authorities is to limit the wastage of doses as much as possible.
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Soeren Stache / AP / SIPA
While Pfizer's vaccine comes with logistical constraints, the government, already criticized for the slowness of the vaccination campaign, has anticipated a risk of loss of "25 to 30% of doses".
To limit the wastage of vaccines, for which demand is very high and supply tight, the European Medicines Agency now recommends taking a sixth dose in each vial.
And while each dose should be administered within six hours of preparation, there is no question of not using any remaining doses.
After a certain slowness at the start, the anti-Covid vaccination campaign must gradually reach its cruising speed in France.
With the deployment of 600 vaccination centers by the end of January, the early opening of vaccination to caregivers over 50, over 75 years outside nursing homes and people with high-risk pathologies, the The objective is to immunize the largest number of vulnerable French people as quickly as possible.
The spread of the English variant, which makes the coronavirus 50 to 74% more contagious, and a possible epidemic rebound adds additional pressure on the executive, who wants to make this campaign a model of exemplarity.
This exemplary nature could be thwarted by a demand for vaccine that is greater than the pace of deliveries, and by a risk of loss of precious doses linked to the storage constraints of the two available vaccines.
So, faced with a risk of tight supply in the months to come, the objective is simple: “zero-waste”.
A high anticipated loss rate
The bomb was dropped on January 3: an adviser to Prime Minister Jean Castex, quoted by
Le Figaro
, indicates that “between 25 and 30% of vaccine doses could be lost” in France due to logistical problems.
According to this estimate, this would mean a loss of 50 to 60 million doses out of the 200 million ordered by Paris.
With the Pfizer vaccine, which must be stored between - 70 and - 80 ° C, all the logistics had to be established to ensure the transport and secure storage of the doses.
And the risk of waste lurks at all stages.
First, any break in the cold chain affects the safety and efficacy of the vaccine, and makes all affected lots safe to throw in the trash.
Since the vaccine is packaged in glass vials, any clumsy gesture is not forgiving either.
What justifies Matignon's fears is indeed the packaging of the vaccine.
“These are multidose vaccines.
With one vial, we can vaccinate five or even six people, said Prof. Odile Launay, infectious disease specialist, coordinator of the Cochin-Pasteur vaccinology center and member of the Covid-19 vaccine committee to Franceinfo.
These vaccines can be kept in the fridge for five days when they are sent to vaccination sites.
However, once prepared, they must be used within six hours ”.
Beyond that, the rest is thrown away.
A reservoir of 20% additional doses
First to arrive on the market, the Pfizer - BioNTech vaccine is therefore delivered in multidose vials.
Each vial of Comirnaty contains 0.45 ml of pure product, to be diluted with 1.8 ml of sodium chloride, also supplied by Pfizer, by a preparer.
Or 2.25 ml of "finished" product to be divided into five doses.
Since the dose to be injected is 0.3 ml per person, up to 0.75 ml of unused product remains per vial.
More than enough to administer a sixth or even a seventh dose.
This represents a reservoir of 20% additional doses.
Faced with the emergency, the European Medicines Agency (EMA) decided to authorize the withdrawal of this sixth dose.
"The EMA's Committee for Medicinal Products for Human Use (CHMP) recommended updating the product information for Comirnaty to specify that each vial contains six doses of the vaccine," the European regulator announced in a statement.
What considerably accelerate things in France and in the rest of Europe.
"References are sent to the various health centers to extract this sixth dose", one indicates on the side of the Ministry of Health.
No seventh dose
The EMA, however, warned that "if standard syringes and needles are used, there may not be enough vaccine to extract a sixth dose from a vial", prescribing the use of appropriate syringes. .
The agency also warned that if a full dose of 0.3 ml is not available in the vial after the fifth dose, "the healthcare professional should throw away the vial and its contents", and not mix the leftovers. “Multiple vials to constitute a complete dose”.
There is therefore no question of taking the route of a seventh dose in the same bottle, as recommended by the Israeli health authorities.
Because in practice, the Pfizer vaccine is quite fatty, and a small part of the dose, "the dead volume", remains on the walls of the vial and syringe, as well as in the needle.
Hence the need for the manufacturer to provide a safety margin to anticipate this loss.
These are all questions that will not arise for Moderna's vaccine, which will be delivered ready to use.
Vaccinate non-priority people with the remaining doses
With messenger RNA vaccines (the Pfizer / BioNTech and Moderna) that do not keep indefinitely after being taken out of the freezers, even the ability to extract a sixth dose is not enough to avoid waste.
Hence the importance of "organizing the appointment well, with pre-vaccination consultations carried out upstream," insists Dr. Luc Duquesnel, general practitioner and president of the general practitioners - Confederation of French medical unions (CSMF).
A patient who comes to be vaccinated without prior vaccination consultation slows down the flow.
With the risk that if he cannot be vaccinated, for example because of an allergic risk, his window has been blocked for nothing, and that in the end the reserved dose will be lost ”.
Another anti-waste approach: vaccinating non-priority people at the end of the day with the remaining doses.
Nursing homes offer them to their staff when, after the passage of residents and staff over 50, all of the doses prepared have not been used.
Ditto in hospitals where vaccination centers have been installed.
"Administering the remaining doses to non-priority caregivers at the end of the day is a good thing," says Dr Duquesnel.
It is out of the question to throw away doses when we already fear a shortage today ”.
Faced with this risk, the European Union has concluded an agreement for the acquisition of 300 million additional doses of the Pfizer / BioNTech vaccine.
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