Coronavirus: Regulator approves plan to stretch supplies of UK Pfizer vaccine

UK has purchased 40 million doses of Pfizer vaccine - enough for 20 million people

Shaun Lintern
Health Correspondent
Tuesday 29 December 2020 16:36 GMT
NHS staff have been told they can try to get a sixth dose from the Pfizer vaccine vials
NHS staff have been told they can try to get a sixth dose from the Pfizer vaccine vials (POOL/AFP via Getty Images)

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NHS staff delivering coronavirus vaccinations to thousands of vulnerable patients have been told they can get an extra dose out of the vials to help stretch supplies even further.

Regulators have approved a plan to try and help make sure as many at risk patients as possible can get the vaccine in the coming weeks.

NHS England’s chief executive Sir Simon Stevens has said he hoped all vulnerable people would be offered a vaccine by late spring. He did not set a specific timetable but a recent study suggests the UK needs to be vaccinating as many as 2 million people a week.

There has been widespread speculation that the Oxford University AstraZenca vaccine will be approved by the Medicines and Healthcare products Regulatory Agency (MHRA) this week.

GPs were told they could stretch the doses to six in a webinar by senior NHS England staff earlier in December but now the MHRA has approved the use.

Until more vaccine is available, official guidance from the Department of Health and Social Care to NHS staff and GPs, which was published on Christmas Eve, said a sixth dose could be possible from the small vials which contain the Pfizer vaccine.

The active vaccine liquid is first diluted with a saline solution and must be used within six hours.

The guidance to staff says the diluted solution will have enough vaccine for five doses but if staff use what are called ‘dead volume syringes’ that limit the excess fluid used its possible to get an extra dose 0.3ml dose.

The document says: “After dilution, the vial contains five doses of 0.3ml. Withdraw the required 0.3ml dose of diluted vaccine using a sterile needle and syringe and administer.

“Vial volume was optimized to reliably obtain five doses regardless of syringe type used as most syringe and needle combinations require withdrawal of excess volume in order to ensure the full 0.3ml dose of vaccine can be administered.

“When low dead-volume syringes and/or needles are used, the amount remaining in the vial after five doses have been extracted may be sufficient for an additional (sixth) dose.”

The guidance said staff must make sure a full dose is given and where a full sixth dose cannot be extracted it must not be mixed with other vials but instead thrown away.

The UK has purchased 40 million doses of the Pfizer vaccine which was approved at the start of the month. This will be enough to protect 20 million people.

The vaccine has been shown to be 95 per cent effective against the virus in clinical trials.

It uses special genetic instructions that tell human cells to make the spike protein found on the outside of the Covid-19 virus. This leads to an immune response from the body, creating antibodies against the spike protein.

If the person becomes infected with the virus the antibodies will be able to lock on the viral cells and prevent infection.

A spokesperson for the MHRA said: “The vaccine is manufactured with enough in each vial to extract five doses. However, a full sixth dose could be extracted in certain cases depending on the type of syringe and needle used.  

“We have amended the product information to state that this is permitted.  However, care needs to be taken to ensure a full 0.3ml dose can be administered to each individual. Where this cannot be achieved when diluted as recommended, the vial and its contents should be discarded after the fifth dose has been extracted.”

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