COVID-19 vaccine Comirnaty from Pfizer/BioNTech: Information for healthcare professionals concerning the sixth vaccine dose

Corona vaccine Comirnaty® (BNT162b2) from Pfizer/BioNTech: up to 6 doses per vial possible


The COVID-19 vaccine Comirnaty® from Pfizer/BioNTech is supplied in a multidose vial. At least 5 units of the specified 0.3 ml individual dose can reliably be withdrawn from the vial regardless of the syringe type used. But with suitable syringes and careful handling, one vial can provide 6 doses, as stated in the Swiss product information approved by Swissmedic.

The volume of the vial has been optimised such that, regardless of the syringe type used, at least 5 vaccine doses of 0.3 ml can reliably be withdrawn. Accordingly, the labels of the product – which is currently distributed in Switzerland in the American packaging – state that, after dilution, each vial contains 5 vaccine doses of 0.3 ml.

If syringes and/or needles with a low dead volume are used, up to 6 doses can be withdrawn from a single vial, as stated in the Swiss Information for healthcare professionals[1].

Whether 5 or 6 vaccine doses can be withdrawn therefore depends on the vaccination materials used. In view of the limited number of vaccines currently available, Swissmedic recommends the withdrawal of 6 doses by proficient specialists using suitable syringes.

It must be ensured that 0.3 ml of vaccine is always administered to a vaccine recipient, and that this dose is withdrawn from a single vial. If a full 0.3 ml dose cannot be withdrawn, the contents must be discarded.

Swissmedic is currently checking, in consultation with the marketing authorisation holder, whether the product information should be revised accordingly, and is taking account of the findings of other drug regulatory authorities.

[1] "After dilution, one vial (0.45 ml) contains 6 doses of 0.3 ml. 1 dose (0.3 ml) contains 30 micrograms of COVID-19-mRNA vaccine (embedded in lipid nanoparticles)."mm COVID-19-mRNA-Impfstoff (in Lipid-Nanopartikel eingebettet).»

Handling instructions (as stated in the Information for healthcare professionals)[2]

  • Comirnaty should be prepared by a healthcare professional using aseptic techniques to ensure the sterility of the prepared dispersion.
  • The multidose vial is stored frozen and must be thawed prior to dilution. Frozen vials should be transferred to an environment of 2 °C to 8 °C to thaw. A 195 vial pack may take 3 hours to thaw. Alternatively, frozen vials may also be thawed for 30 minutes at temperatures of up to 30 °C for immediate use.
  • Allow a thawed vial to come to room temperature and gently invert it 10 times prior to dilution. Do not shake.
  • Prior to dilution, the thawed dispersion may contain white to off-white opaque amorphous particles.
  • The thawed vaccine must be diluted in its original vial with 1.8 ml of 0.9% sodium chloride solution for injection (9 mg/ml) using a 21 gauge or narrower needle and an aseptic technique.
  • Equalise vial pressure before removing the needle by withdrawing 1.8 ml of air into the empty diluent syringe.
  • Gently invert the diluted dispersion 10 times. Do not shake.
  • The diluted vaccine should present as an off-white dispersion with no visible particulates. Discard the diluted vaccine if particulates or discolouration are present.
  • The vials with the diluted solution should be marked with the new discard date and time.
  • Do not freeze or shake the diluted dispersion. Allow the refrigerated, diluted dispersion to come to room temperature prior to use.
  • After dilution, the vial contains 2.25 ml, corresponding to 6 doses of 0.3 ml. Withdraw the required 0.3 ml dose of diluted vaccine using a syringe and/or sterile needle, each with a low dead volume. Use a separate sterile needle and syringe for each person. Provided the needle has not been damaged or contaminated, it is not necessary to change the needles between the withdrawal of the vaccine from a vial and the administration of the injection to the recipient.
  • Discard any unused vaccine within 6 hours after dilution.

[2] as at 31 Dec. 2020

Supplementary information