No evidence Covid-19 vaccine makes blood look different

22 September 2021
What was claimed

A photo shows two bags of donated blood, one lighter red and one almost black, and says the redder one is from a non-vaccinated person and the darker one is from a vaccinated person.

Our verdict

NHS Blood and Transplant says it has observed no difference between vaccinated and unvaccinated people’s blood.

A post on Instagram which claims to show two bags of donated blood, one much darker than the other, says that the lighter red one is from someone who has not been vaccinated, and the bag that’s almost black is from someone who has been vaccinated.

We’ve also seen this claim on Twitter.

Although the post doesn’t specifically mention the Covid-19 vaccination, we’re assuming this is what they are referring to when they say “non vax vs. Vax”.

We asked NHS Blood and Transplant whether it had observed differences in blood from vaccinated and unvaccinated donors. It said it had not.

There is a certain amount of variation expected in colour between different donors’ blood, but this doesn’t necessarily indicate a health issue in the donor or mean the blood can’t be used by a patient.

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Donating blood after vaccination

As a precautionary measure, in the UK you must wait seven days from your Covid-19 vaccine date before donating blood. The NHS says this is because “​​any side effects [from the vaccine] are unlikely to be confused with illness after donating.” 

If you have side effects following the vaccine, you must wait 28 days after recovering from them to donate blood.

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