Increasing vaccine supply with low dead-volume syringes and needles.

As global vaccine production capacity is limited, every optimization strategy must be explored to rapidly increase the number of people vaccinated. The objective of this study is to determine which medical devices allow the extraction of the maximum number of doses from different vaccine vials (Pfizer-BioNTech, AstraZeneca, Moderna and Johnson & Johnson vaccines) by analyzing all the factors involved in the preparation of the injected doses. By measuring the dead-volume of 32 syringe-needle combinations, we show that fixed-needle syringe with a dead-volume of less than 5 µL can extract up to 7 doses from Pfizer vials, 13 doses from AstraZeneca vials, 12 doses from Moderna vials and 6 doses from Johnson & Johnson vials. We found that the syringe accuracy is important, and can compromise the chances of extracting additional doses when withdrawing too large a volume. For Pfizer vaccine, particular attention must be paid to the choice of dilution syringe, which may compromise the extraction of the 7th dose. The withdrawal of extra doses from vaccine vials was not operator-dependent. In this unprecedented health context, the medical device considerations presented here could help to optimize every COVID-19 vaccine vial.