Why Can’t You Give Blood After Getting a Vaccine?

If you are like most people, you have heard so much anti-vaccine misinformation that you figure it is safe to assume that everything these folks say isn’t true.

Yes, go research shedding

If you are a true skeptic, you will still do your research on any new claims just to make sure.

Why Can’t You Give Blood After Getting a Vaccine?

Although you may not have heard of any restrictions on donating blood after getting vaccinated before, it makes sense once you think of it.

You actually have to wait:

  • for up to 8 weeks after getting the smallpox vaccine
  • for up to 4 weeks after getting the MMR (because of the rubella component), chickenpox, and Zostavax vaccines.
  • for up to 3 weeks after getting the hepatitis B vaccine
  • for up to 2 weeks after getting the measles, mumps, oral polio, or yellow fever vaccines

If you notice that these are almost all live vaccines, it becomes very easy to see why you can’t donate blood shortly after being vaccinated.

Blood donation is “Acceptable if you were vaccinated for influenza, tetanus or meningitis, providing you are symptom-free and fever-free. Includes the Tdap vaccine. Acceptable if you received an HPV Vaccine (example, Gardasil).”

American Red Cross Eligibility Criteria: Alphabetical

Live vaccines can create a temporary viremia (virus particles in the blood), which could then be transferred to someone else in donated blood.

Could you get an infection this way?

Probably not.

Remember, you would only be getting the attenuated or weakened vaccine virus strain and even then, it would be a very small amount. If the person getting the vaccine doesn’t get sick from getting the vaccine, why would someone who was getting a much smaller dose through a blood donation.

Still, there is a theoretical risk, especially if the person who received the blood donation had an immunodeficiency, so people aren’t supposed to donate blood shortly after getting these vaccines.

But what about the hepatitis B vaccine. It isn’t a live virus vaccine.

The risk with this vaccine is that a very recently vaccinated donor might test positive for HBsAg (this only happens temporarily), leading the donation center to actually think that they had a hepatitis B infection, disqualifying them from ever donating blood again.

Does any of this mean that vaccines aren’t safe?

Of course not!

Just consider some of the other restrictions on donating blood:

  • You are not eligible to ever donate if you ever tested positive for hepatitis B, even if you were never sick.
  • You must wait 12 months after your last contact if you were exposed to someone with hepatitis B and you want to donate blood.
  • If you are unvaccinated, you must wait at least 4 weeks after being exposed to someone with measles.

So yes, that means that you will be much more likely to be eligible to donate blood if you are fully vaccinated and protected.

More on Donating Blood After Getting Vaccinated

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