A shortage of speciality syringes is challenging plans to get an extra dose of the Pfizer-BioNtech coronavirus vaccine out of its vial, medical device giant Becton Dickinson (BD) said.

"Low dead space syringes" can be used to extract six doses instead of five from vials containing the companies' vaccine, but a BD spokesman told AFP on Saturday there is a supply crunch for the syringes and no easy way to address it.

"Low dead space syringes are niche products and there has... traditionally been minimal market demand based on health care provider needs," the spokesman said.

"Because of this, those products have limited production capacity, and it would take time to increase production capacity of these device."

It's possible to get six doses from vials of the Pfizer-BioNtech Covid-19 vaccine rather than five, but only with a special syringe
It's possible to get six doses from vials of the Pfizer-BioNtech Covid-19 vaccine rather than five, but only with a special syringe AFP / MEHDI FEDOUACH

Newly-installed US President Joe Biden has vowed to employ the Defense Production Act to increase industrial output of key medical supplies and set a target of getting 100 million vaccinations administered in his first 100 days in office.

However, that quest would be made more difficult if a lack of the speciality syringes wastes the extra shot of the Pfizer-BioNtech vaccine, which along with Moderna's vaccine is one of two inoculations against the virus authorized in the United States.

When BD began working with US officials last spring, "there was no emphasis placed on low dead space syringes, so other devices took priority when production was ramped up to meet Covid vaccination needs," the spokesman said.

The company "is proactively collaborating with the US government to discuss capabilities for low dead space devices," he said.