As the worldwide vaccination, it is imperative to minimize vaccine wastage by effectively using all doses available . Vaccine wastage can occur at multiple points during the vaccination process, but it is mainly because the device dead space and the filling process technique . However, there are no studies discussing the waste volume effect of COVID-19 vaccines in clinical practice . There is an increasing COVID-19 vaccine demand that we estimate up to several billion dual doses . The objective of this study was to assess the number of 0.3mL doses obtained from a multiple-dose vial using 1ml and 3ml syringes with different type of needles replicating the first COVID-19 vaccination protocol . Our results suggest that it is possible to obtain six or seven doses from each vial instead five . We provide evidence to optimize between 20% and 40% additional vaccine doses per vial if the current 5-dose vials are used, making scarce supplies go further . It is our duty, as researchers, to ensure the efficacy and efficiency of the worldwide COVID-19 vaccination process . However, if standard syringes-needles and technique are used, there may not be sufficient volume to draw extra doses from a single vial.