Did Pfizer include tromethamine, an "ingredient used to stabilize heart attack victims" in its COVID-19 vaccine for children aged 5-11 years old? Only as a stabilizing pH buffer to make it easier to store. While tromethamine is being used as an inactive ingredient in the Pfizer-BioNTech COVID-19 vaccine authorized for use in children aged 5-11 years old, both Pfizer and the U.S. Food and Drug Administration (FDA) told Lead Stories that the addition of the ingredient is not harmful.
The claim appeared in an article (archived here) titled "Pfizer adds ingredient used to stabilize heart attack victims in vax for kids," published by Press California on October 28, 2021. After citing a meeting briefing document from the FDA about Pfizer's request to modify its COVID-19 vaccine for individuals aged 5-11 years old to include tromethamine, the article read:
Tromethamine (Tris) is a blood acid reducer which is used to stabilize people with heart attacks. Here are known side effects: Respiratory depression, local irritation, tissue inflammation, injection site infection, febrile response, chemical phlebitis, venospasm (vein spasms), hypervolemia, IV thrombosis, extravasation (with possible necrosis and sloughing of tissues), transient decreases in blood glucose concentrations, hypoglycemia, and hepatocellular necrosis with infusion via low-lying umbilical venous catheters
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Buried on Page 14 in the Pfizer paperwork submitted to the FDA for the Covid vaccine for children is this disturbing nugget. Vaccine formulation Authorization is being requested for a modified formulation of the Pfizer‑BioNTech COVID-19 Vaccine. Each dose of this formulation contains 10 μg of a nucleoside-modified messenger RNA (mRNA) encoding the viral spike...
Tromethamine, like many drugs, is used for a variety of medical procedures including cardiac bypass surgery; and like every drug, it may cause side effects. However, in an email to Lead Stories on November 3, 2021, Pfizer's media relations team said:
The manufacturing processes involved in producing the pediatric doses remain unchanged from the adult and adolescent doses. There are also no changes in raw materials, mRNA, lipids or suppliers in the manufacturing of the drug substance and lipid nanoparticles (LNPs). To enable extended storage time an alternative buffer is being leveraged, known as a 'tris buffer'. Simply put, this allows the mRNA to resist being degraded for a longer period of time before administration - meaning the pediatric vaccine can be stored for 2-8°C in commonly available refrigerators for up to 10 weeks. This buffer will also be used in the updated adult/adolescent 30mcg doses in due course, helping to ensure simplified handling of the vaccine across age groups. To reiterate, the manufacturing processes involved in producing the pediatric doses remain unchanged.
Lead Stories also reached out to the FDA for more information about the inclusion of tromethamine in Pfizer's COVID-19 vaccine. In an email on November 3, 2021, Alison Hunt, a press officer for the FDA, told us:
The Pfizer-BioNTech COVID-19 Vaccine for children 5 through 11 years of age contains a lower amount of mRNA per dose than that used for individuals 12 years of age and older. It is a modified formulation that contains a tromethamine (Tris) buffer instead of the phosphate-buffered saline used in the original formulation of the Pfizer-BioNTech COVID-19 Vaccine. Buffers help maintain a vaccine's pH (a measure of how acidic or alkaline a solution is) and stability. This will provide a vaccine with an improved stability profile that can be kept refrigerated longer and can be readily delivered in appropriate doses for the 5 through 11 age group. Both the modified formulation and the original formulation will be available for the 12 and older age group.
The same buffer, Tris, that is used in the vaccine's new formulation has been used in licensed (approved) vaccines including: Dengvaxia (Dengue Tetravalent Vaccine, Live), Jynneos (Smallpox and Monkeypox Vaccine, Live, Non-Replicating), and Ervebo (Ebola Zaire Vaccine, Live). As with all licensed or authorized vaccines, the manufacturing of the vaccine adheres to current good manufacturing practices in accordance with FDA standards.
Hunt also referred us to information from an FDA virtual press conference about the Pfizer-BioNTech COVID-19 vaccine for children aged 5-11 held on October 29, 2021. The conference featured Peter Marks, director of the FDA's Center for Biologics Evaluation and Research. At the 6:19 mark of the video, Marks began to discuss the use of the tris buffer in Pfizer's COVID-19 vaccine and at 6:55 said:
The FDA-evaluated manufacturing data support the change in this inactive ingredient and concluded it did not impact the safety or effectiveness of the product.
More information about updated vaccine can be found in this FDA press release.
Tromethamine has also always been used as an ingredient in the Moderna COVID-19 vaccine.
More Lead Stories coverage of the novel coronavirus and COVID-19 can be found here.