Should You Worry About Vaccine Allergic Reactions?

I recently spoke with a friend who expressed concern about getting the SARS-CoV-2 vaccine because of the possibility of having an allergic reaction to it. Is this a reasonable concern? Not if you put it in the context of other things you do every day that carry a higher risk.  

The latest information from the CDC says that the rate of anaphylaxis from the Pfizer vaccine is 6.2 per million, which works out to a 1 in 161,290 chance. For the Moderna vaccine the rate was even lower at 2.1 per million, which is 1 in 476,190.

Other Risks

The National Safety Council publishes a handy list of the risk of dying from various everyday activities. For some reason the latest data are from 2018, but it's probably safe to assume that the risks haven't changed a lot in three years. Here are some of the things in a given year that are more likely to kill you than experience  anaphylaxis from either vaccine:

  • Dog attack: 1 in 118,776
  • Hornet/wasp/bee sting: 1 in 53,989
  • Gun accident: 1 in 9,077
  • Choking on food: 1 in 2,618
  • Motor-vehicle crash: 1 in 106

(The odds of dying from a lightning strike are 1 in 180,746 which is a little lower than the Pfizer vaccine, but higher than the Moderna vaccine.)

Also note that we are only comparing these risks to having anaphylaxis, not dying from it. In most cases it is easily treatable. Deaths from all causes of anaphylaxis are in fractions per million.  More important, there have been no reported deaths from anaphylaxis associated with the Moderna vaccine (see here) or the Pfizer-BioNTech vaccine (see here).

Alternative Is Much Riskier

How do the above risks compare to the risk of dying from COVID-19? It turns out that's hard to say in general because you have to get the disease before you can die from it. Your risk of getting it depends on a whole slew of factors, like what you do to expose yourself, what mitigation steps you take, and most of all what the population infection rate is. We don't know that because we don't have random testing.

The chances of dying if infected depend on age and risk groups. However, epidemiologists I spoke to said that currently in Arizona, the chance of dying if you have a positive case is about 1.7%, which works out to 1 in 59.

Bottom Line

If you are around dogs, hornets/wasps/bees, or guns, or if you eat or drive, you are more likely to die from any of these things than to have anaphylaxis from either vaccine. If you did have the reaction and die, you'd be the first one. On the other hand, your risk of dying from COVID-19 (if you get it) is 2,733 times higher than having the reaction—which again, has yet to kill anyone.


 "Syringe and Vaccine" by NIAID is licensed under CC BY 2.0 

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