Extracting seven doses per vial of Pfizer’s Covid vaccine is possible but Spain and Europe rule out imposing it

Healthcare professionals have managed to get an ‘extra’ dose from the Pfizer and Biontech antigen vials, which should only contain six.

Pfizer vaccine units arrived in the Valencian Community.  EE

The vaccination campaign against Covid is advancing in the European Union. After the first obstacles posed by the organization and training of health professionals, the greatest challenge now facing states is the shortage of vaccines. However, there may be a palliative for this situation: health professionals, with the appropriate equipment and the precise experience, have managed to extract an ‘extra’ dose of the Pfizer and Biontech antigen vials, which should only contain six. But nevertheless, neither Spain nor the European Union are considering imposing the extraction of this seventh dose of vaccine in the technical sheet.

The technical data sheet for Comirnaty, the commercial name of Pfizer’s vaccine, states that after dilution, “The vials contain six doses of 0.3 ml of vaccine“.

A solution (after extraction of the preparation) that, if it is rushed to the maximum and thanks to its overfilling, can remove seven doses from a single vial. To do this, syringes or needles with low dead volume and great technical precision must be used so that, by squeezing the origin dial to the maximum, up to seven injections are diluted.

A vaccination.

A vaccination.

The specialized medium ‘Medical Writing’ has advanced this evidence that Invertia has contrasted. Health professionals consulted by this means believe that taking this seventh dose is possible “In some cases” but which entails great technical complexity. Without going into whether the protocol should be adapted or not, they insist on using the appropriate material.

In fact, they assure that it is hasty to talk about seven doses when the gear to get the sixth dose is not yet fully working. From the Spanish Association of Nursing and Vaccines, Anenvac, insist that some CCAA are still not extracting the sixth dose.

The headquarters of the European Medicines Agency (EMA) in Amsterdam

The headquarters of the European Medicines Agency (EMA) in Amsterdam

For now, Europe does not have on the table to approve a seventh dose per vial. From the European Medicines Agency (EMA) itself they rule out this possibility. Above all because no one has made an official request about it, not even Pfizer itself.

However, sources close to both the EMA and the Ministry of Health indicate that the possibility of officially including a seventh dose is ruled out, at least for now. Why? Because you cannot ‘get’ seven doses from each vial in a generalized way.

As a certain Andalusian Health Minister said, in all the vials there is a ‘culillo’ of antigen. Enough to get a dose? Not always and not in all situations, these sources warn. The seventh dose of the Pfizer vaccine cannot be generalized, despite having the aforementioned special needles that have allowed the sixth dose to be included in the technical data sheet.


The case of the AstraZeneca and Oxford vaccine it is still under analysis. From the EMA they indicate that the Agency itself raised “the question of whether or not low dead volume syringes should be recommended for the AstraZeneca Covid vaccine during the evaluation of the marketing authorization file and the applicant was asked to provide further data later. to authorization ”.

They are waiting for them. “If these data show that an additional dose can be consistently drawn from the vials, the product information will be updated accordingly.”

AstraZeneca’s vaccine is available today in two formats: 8-dose and 10-dose vials. If the company presents the aforementioned data that support the extra dose per vial, they will have nine and eleven doses respectively..

As in the case of Pfizer, this would have a paradoxical effect: as each vial would contain more approved doses, the company would be able to deliver fewer vials, although each container is not used properly.

Boris Johnson with a vial of AstraZeneca vaccine.

Boris Johnson with a vial of AstraZeneca vaccine.
FW1F/Catherine EvansReuters

It should be remembered that the contracts that the pharmaceutical companies have signed are by dose, not by vials. Pfizer has already reduced the number of vials to deliver. Will AstraZeneca do the same? We will have to be on the lookout.

Regarding the AstraZeneca vaccine, healthcare professionals are hesitant to talk about an extra dose. They do insist on the need to use dead volume needles and syringes to get the best performance.

Even so, this vision is not far-fetched, since, Oxford preparation vials also come with overfill as with the Pfizer preparation.