Pfizer vaccine, blood transfusions, and Janssen blood clots

The Buzz wondered if those injected with the covid-19 Pfizer gene therapy jab would pose any risks to those who opt not to be vaccinated when it come to receiving donated blood and transfusions… Here is the New Zealand Blood Service‘s responses to our questions.

1.      Are there any risks to the health of a person who has been vaccinated with one type of Covid vaccine and then later receives blood from someone who has had a different type Covid vaccine?

A: The safety of New Zealand’s blood and blood product supply is always a priority and we defer donors when there is evidence that a drug or condition may negatively affect the quality of the blood transfused.

As there will not be any vaccine in the blood stream from our donors, we do not believe that there is any danger to a recipient receiving blood from someone who has had a different vaccine. With the Pfizer vaccine, we have a 12 hour stand down.

The active component of the Pfizer vaccine (MRNA) is quickly broken down and does not persist in the body outside the muscle cells for more than a few hours.

The spike protein, that the vaccine induces, is attached to the muscle cell and does not appear in the blood stream. Any donor who received a vaccine that has not been approved for use in New Zealand has a 28 days stand down.

This will ensure that there is no vaccine in the donor’s blood. Should other vaccines be approved for use in New Zealand, we will review the specific vaccine and determine an appropriate stand down period based on its mechanism of action.

2.      Should someone need blood who has chosen not to be vaccinated, and then later receives blood from someone who has, will the recipient be as good as vaccinated?

A: A recipient of blood from a vaccinated donor will not have been vaccinated. The Pfizer vaccine is not transmitted by blood.

The donor blood may contain some antibodies to Covid19 but these will be broken down over weeks to a few months, like all antibodies are. The recipient will not have any immunity of their own.

3.      Will NZ Blood service document on its blood products whether the blood is that of a vaccinated donor?

A: No, we will not be documenting on the blood whether a donor has been vaccinated. Donors have many different types of antibodies in their blood and antibodies to Covid19 are just one more.

The Pfizer vaccine is not transmitted by blood transfusion. All other vaccines not approved by Medsafe have a lengthy stand down period for the donor, so will not appear in the blood either.

4.      What tests is NZ Blood doing to see what effect, if any, Covid vaccinations are having on blood and blood products?

A: New Zealand Blood Service (NZBS) are not testing to determine if Covid19 vaccinations are having any effect on blood. Blood services internationally, including NZBS, have a good understanding of vaccination in relation to blood donation.

NZBS shares information and discussion with other blood services around new medicines and vaccines, including Covid19, to determine if any services have identified potential impact on the quality and safety of blood products. 

Both NZBS and other blood services have not identified any blood safety concerns about the Pfizer vaccine that is in use in New Zealand.

Answers supplied by the Executive Assistant to CEO & Director of Finance – New Zealand Blood Service.

Janssen blood clots

In addition Sarah Morley, NZ Blood’s Chief Medical Officer, writes: “Certain COVID vaccines have been linked to a very rare clotting and bleeding complication called Thrombosis with Thrombocytopenia Syndrome (TTS). 

“This complication has not been associated with the Pfizer vaccine in use in New Zealand but with the two DNA vector vaccines (Astra Zeneca and Janssen*). 

“I have included a link about TTS from NZBlood.

“The underlying mechanism for TTS is not yet fully elucidated. I have seen nothing to suggest that the spike vaccine is the primary driver for this condition. 

“The Pfizer vaccine does not contain spike protein, only the code that allows cells to make it. The spike protein will be generated on cells that absorb the vaccine, but the protein may be present, only in trace amounts, in the blood. 

“NZ Blood Service is not concerned that trace amounts of spike protein affect the quality of blood collected for transfusion.”

*Janssen was given the ‘all clear’ by Medsafe to be used in New Zealand on 12 July 2021.

Medafe’s official Gazette PDF notices for Janssen:

Rare syndrome of blood clots

Medsafe says on its website (27 April 2021): “Medsafe has finished an initial evaluation of international reports of a rare syndrome of blood clots (thrombosis) occurring with bleeding (due to thrombocytopenia) and platelet factor 4 antibodies.

“To date, all the cases that have been reported after vaccination are linked to the first dose of Vaxzevria (AstraZeneca) or the Janssen COVID-19 vaccines. These vaccines are not currently used in New Zealand (see above*).

“There have been reports of blood clots internationally after vaccination with Comirnaty. Medsafe’s assessment is that there is no indication that these cases are in any way similar to the TTS cases reported with the other COVID-19 vaccines.

“This assessment was endorsed by New Zealand’s COVID-19 Vaccine Independent Safety Monitoring Board (CV-ISMB) on 22 April 2021 (see table below).

“Up to 22 April 2021, the Centre for Adverse Reaction Monitoring (CARM) has received three cases of thrombosis (one stroke, one deep vein thrombosis and one cerebral venous sinus thrombosis). There was no evidence of bleeding in any of these cases.

“Following review by CARM and the CV-ISMB, none of these cases was considered to be related to vaccination.

“The number of cases of thrombosis reported following vaccination is lower than the expected number occurring without vaccination. There are over 3,000 cases of thromboembolism and more than 10,000 cases of stroke requiring hospital treatment per year in New Zealand.”

COVID-19 Vaccine Independent Safety Monitoring Board

NameArea of ExpertisePosition
Mr John Tait (Chair)Obstetrics, Clinical Governance, and Leadership.Chief Medical Officer CCDHB; Consultant obstetrician and gynaecologist
Dr Nick CutfieldNeurologyConsultant Neurologist and Clinical Lead; Senior Lecturer
Associate Professor Matt DoogueClinical Pharmacology; EndocrinologyConsultant physician in Clinical Pharmacology and General Medicine
Dr Kyle EggletonGeneral PracticeKaupapa Māori Medical Officer at Ki A Ora Ngātiwai; Senior Lecturer
Professor Chris FramptonBiostatisticsProfessor of Biostatistics
Dr Maryann HeatherGeneral Practice; Pacific HealthGP at South Seas Healthcare; Senior Lecturer
Dr Tom HillsImmunologyChief Medical Resident, Immunology
Honorary Associate Professor Hilary LonghurstImmunology; PathologySenior Medical Officer, Immunology
Professor Thomas LumleyBiostatisticsProfessor of Biostatistics
Saskia SchuitemakerLay person – to represent consumer interestsCoordinator, Child and Youth Mortality review Group, Waikato District Health Board
Dr Owen Sinclair, Te RarawaPaediatrics, Māori HealthPaediatrician WDHB
Professor Lisa StampRheumatologyProfessor in Medicine; Rheumatologist
Dr Anja WernoMicrobiology; PathologyChief of Pathology & Medical Director of Microbiology, CHL; Clinical Senior Lecturer
Dr Enver YousufGeneral MedicineSenior Registrar CCDHB General Medicine