Extra dose from vials of Comirnaty COVID-19 vaccine
In order to extract six doses from a single vial, low dead-volume syringes and/or needles should be used. The low dead-volume syringe and needle combination should have a dead volume of no more than 35 microliters. If standard syringes and needles are used, there may not be enough of the vaccine to extract a sixth dose from a vial.
If the amount of vaccine remaining in the vial after the fifth dose cannot provide a full dose (0.3 ml), the healthcare professional must discard the vial and its contents. There should be no pooling from multiple vials to make up a full dose, and any unused vaccine should be discarded 6 hours after dilution. Further information on all the steps for using Comirnaty is available in the updated product information.
The company that markets Comirnaty has published a list of low dead-volume syringes and needles with relevant suppliers. This list is available on their website which can be accessed via the QR code on the vial tray label and in the package leaflet.*
Comirnaty is a vaccine for preventing coronavirus disease 2019 (COVID-19) in people aged 16 years and older. It was authorised in the EU on 21 December 2020.
Information for healthcare professionals
- After dilution, it is possible to obtain six doses from a vial if you use low dead-volume (≤35 μL) syringes and/or needles for all doses.
- Discard the vial and its contents if the amount of vaccine left in the vial is not enough for a full sixth dose (0.3 ml).
- Do not pool from multiple vials to make up an extra dose.
- Discard any unused vaccine 6 hours after dilution.
- Read the product information for full instructions.
More about the vaccine
Comirnaty is a vaccine for preventing coronavirus disease 2019 (COVID-19) in people aged 16 years and older.
It contains a molecule called messenger RNA (mRNA) with instructions for producing a protein from SARS-CoV-2, the virus that causes COVID-19. The vaccine works by preparing the body to attack the spike protein on the surface of SARS-CoV-2.
For more information see Comirnaty.
*This paragraph was added on 20 January 2021 to provide information on the list of low dead-volume syringes and needles with relevant suppliers.