Maximizing number of doses drawn from multi-dose COVID-19 vaccines by minimizing dead volume.

The COVID-19 pandemic constitutes an unprecedented challenge to health care systems and societies worldwide. On 21 December 2020, the highly effective Pfizer–BioNTech COVID-19 vaccine was authorized in Europe, bringing big hopes for overcoming the pandemic.1 However, there are concerns about delayed availability of sufficient vaccine doses, forcing to prioritize target populations.2 Vaccination with the Pfizer–BioNTech COVID-19 vaccine consists of two doses (0.3 ml each) administered intramuscularly, 3 weeks apart. Each vial (2.25 ml theorical and 2.27 ml actual volume after dilution) meet the requirements of the European Pharmacopoeia allowing to obtain five doses using a syringe of a capacity not exceeding three times the volume to be measured and fitted with a 21-G needle not less than 2.5 cm in length.3 On 8 January 2021, European Medicines Agency announced that six doses could be extracted from a single vial using low dead-volume syringes and/or needles; i.e. no more than 35 μl for the syringe–needle combination.4 To date, no study has been carried out to propose recommendations on the use of adapted equipment. Here, we report the dead-volume of different syringe–needle combinations in order to inform such debate by relevant medical devices data.