The American group Becton Dickinson, the largest producer of syringes in the world, said on January 25 that the production of syringes needed to extract six doses instead of five from a vial of Pfizer-BioNtech’s Covid vaccine remained for the moment “limited”.

According to Pfizer, the vaccine vials initially contained five “official” doses, but caregivers quickly realized they could sometimes get at least a sixth dose, or even a seventh. One way to speed up vaccination.

Read also: Vaccination: the 6th dose that divides

Where does the sixth dose come from?

Drug agencies in Europe and the United States confirmed in early January that the vials could well contain six doses. But with regular syringes, there is vaccine left inside the needle after the injection is done. This small amount of vaccine fluid is called “dead volume”.

The sixth dose is actually the amount of vaccine Pfizer anticipated as dead volume. Since it only takes a very small amount of product to vaccinate a person, a sixth dose can be made using a syringe that retains less dead volume.

A specific syringe

According to Dr. Jérôme Marty, president of the UFML union, to obtain this sixth dose, “you must have needles which do not have too large a dead volume. As the quantity of vaccine per patient is very low (0.3 ml) , it requires to be precise. “

According to him, recovering this sixth dose is very difficult without a specific syringe, called a crimped syringe. “With the right equipment, the sixth dose is almost systematic. But without it, it’s more DIY and it requires careful attention. You only get it once or two out of three.”

“Niche” products

However, these are “niche products” and the demand for these crimped syringes “is traditionally minimal”, said in a message to AFP a spokesperson for Becton Dickinson, Troy Kirkpatrick. “For this reason, these products have a limited production capacity and it would take time” to increase it, he added.

When presenting its pandemic plan last week, the new US government highlighted the potential shortage of several medical products, including low dead space syringes.

Becton Dickinson has pledged to produce a total of more than one billion syringes for vaccination against Covid-19, including 286 million in the United States. It had already delivered 150 million in late 2020 in the country and plans to distribute the rest by March.