Tromethamine in the Pfizer/BioNTech COVID-19 Vaccine has nothing to do with heart attacks — Deplatform Disease

In my last post, I explained that the Pfizer vaccine for children aged 5 to 11 has been slightly modified with respect to an inactive ingredient: the buffer. Buffers are substances that resist changes to pH (the acidity or alkalinity of a solution). Buffers are a very important component of mRNA vaccines (really all vaccines but mRNA vaccines especially) because mRNA does not tolerate alkaline conditions, which the buffer helps to ensure do not occur in the vial. Specifically, under alkaline conditions, mRNA will undergo a reaction called hydrolysis and rip itself apart. If this happens, our cells don’t get the instructions needed to make the spike protein, which means our immune system doesn’t get to initiate a response against it, and so the vaccine doesn’t work. The shift to a tromethamine (also known as tris or more formally tris(hydroxymethyl)aminomethane) buffer from the original PBS (phosphate-buffered saline) buffer formulation allows the Pfizer/BioNTech COVID-19 vaccine to be stored at standard refrigeration temperatures for up to 10 weeks, whereas before this it had to be stored under ultracold conditions (-80 °C and then -20 °C but for at most 2 weeks). The fact that the buffer was changed and the storage conditions are more relaxed means that the vaccine can be readily given in pediatrician’s offices as they now no longer need to buy very fancy, expensive freezers that are far beyond their budget. Incidentally, this is also the buffer that is used in the Moderna vaccine, as well as for the ERVEBO Ebola vaccine. The old phosphate buffered saline solution (PBS) did the same thing, but Pfizer did additional studies that showed that the mRNA lasted for longer at higher refrigeration temperatures so they switched to that. This is discussed at length in the VRBPAC meeting. There’s really nothing nefarious here. It’s an inactive ingredient- it does not affect the safety or effectiveness of the vaccine- it just makes it easier to give out to people. Unfortunately, this has not stopped some from lying about what its inclusion in the vaccine means.

A screenshot containing misinformation alleging that tromethamine in the Pfizer vaccine is dangerous and also used to treat heart attacks. Essentially no part of this is accurate, as I explain shortly.

I write about vaccines here. You can find me on Twitter @enirenberg and at deplatformdisease.com (where I publish the same content without a paywall)

I write about vaccines here. You can find me on Twitter @enirenberg and at deplatformdisease.com (where I publish the same content without a paywall)