[Editorial update: 26 April, 12:45pm] We have updated the article with clarification from HSA. The rating has been changed from likely false to false.
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We came across this message being forwarded on a Singapore-based Telegram group:
According to the author of the message, blood taken from unvaccinated individuals is “preferred for transfusions in surgeries and blood replacement”.
It is uncertain who the author is, and where they got their information from.
Vaccines affecting one’s blood?
Blood-related claims are not new. Last October, we came across an image being circulated via multiple posts on Facebook:
The claim purports that while blood from unvaccinated individuals “looks reddish and alive”, those from vaccinated individuals “looks downright scary and purplish black” and one should therefore ensure that they’re getting a blood transfusion from an unvaccinated individual.
The claim was quickly debunked by multiple fact-checkers, all of whom reached out to experts for comment. Skyler Johnson, an assistant professor at the Department of Radiation Oncology at Huntsman Cancer Institute, University of Utah School of Medicine, told Reuters that the bags of blood “likely represent a venous blood draw (darker) and an arterial blood draw”, “and could even be from the same patient”.
A fact-check by US Today also consulted Dr. Pampee Young, chief medical officer of biomedical services at the American Red Cross, who stated that “At the American Red Cross, we visually inspect all donated units and have not seen that COVID-19 vaccinated blood units change the colour of blood.”
Vaccines potentially causing blood clots has also been a common rhetoric among the anti-vaccination crowd, and while scientists did find a link between AstraZeneca and Johnson & Johnson’s COVID-19 vaccines and blood clots, these instances are known to be rare. That said, there is also no evidence that mRNA vaccines (like the ones by Pfizer and Moderna) cause blood clots.
As for potential concerns regarding blood donation post-vaccination, the Singapore Health Sciences Authority’s (HSA) website indicates varying deferral periods for different types of vaccines.
For example, the minimum deferral period of one week applies for individuals who took the mRNA (Pfizer, Moderna) or inactivated virus (Sinovac, Sinopharm) vaccines with no side effects. However, if these individuals experience side effects, the deferral periods range from one to four weeks after the side effects have been resolved.
The deferral period is slightly different for individuals who take a live-attenuated (AstraZeneca, J&J) vaccine, and a minimum 4-week wait is necessary even if one does not experience any side effects.
HSA explained that this is due to patient safety consideration, because blood from a recently vaccinated donor may contain an infective agent which although not harmful to the donor, may theoretically pose a risk to patients who are immune-suppressed or immunocompromised such as cancer patients.
We reached out to HSA for clarification on whether or not vaccination status affects a potential donor’s eligibility, and a representative has clarified that “vaccines do not change the donation criteria”.
Said HSA: “A donor has certain waiting time after vaccination for blood donation, however, this doesn’t change the blood status. All the donated blood products go through the required infectious disease tests irrespective of vaccinated or non-vaccinated donor and then only the blood products are released.”
“There is no truth to the fact that unvaccinated blood is considered better for surgeries and blood replacements.”
Therefore, while it is true that individuals should adhere to the deferral period post-vaccination as advised, it is false that the blood of unvaccinated individuals are “preferred for transfusions in surgeries and blood replacement”.
