Sunday, December 27, 2020

Scientists Scramble To Determine Basis Of Covid Vaccine Allergic Reactions

CDC Issues New Guidance on COVID-19 Vaccinations for People With Underlying Medical Conditions

People with underlying medical conditions are able to receive the COVID-19 vaccination as long as they have not had a severe allergic reaction to any of the ingredients, the Centers for Disease Control and Prevention (CDC) said.

The CDC issued new guidance on Saturday aimed at helping adults with underlying health conditions or weakened immune systems to decide whether the newly released COVID-19 vaccine is appropriate for them.

“Adults of any age with certain underlying medical conditions are at increased risk for severe illness from the virus that causes COVID-19,” the guidance says.

The vaccines that are approved by the Food and Drug Administration (FDA) “may be administered to people with underlying medical conditions provided they have not had a severe allergic reaction to any of the ingredients in the vaccine,” it added.

The guidance states that people with weakened immune systems or autoimmune conditions may receive the COVID-19 vaccine but should be aware that little to no data is currently available on the safety of the vaccine for those individuals.

“Our conditions for use, is what we call them, specifically states that, if you have an allergy to any component of the Pfizer/BioNTech vaccine, you should not receive it,” Dr. Stephen Hahn, commissioner of the Food and Drug Administration (FDA), said on CNN’s “State of the Union.”

The ingredients of the Pfizer/BioNTech vaccine (pdf) are listed as follows:messenger ribonucleic acid (mRNA), lipids ((4-hydroxybutyl)azanediyl)bis(hexane-6,1-diyl)bis(2-hexyldecanoate), 2 [(polyethylene glycol)-2000]-N,N-ditetradecylacetamide, 1,2-Distearoyl-sn-glycero-3- phosphocholine, and cholesterol), potassium chloride, monobasic potassium phosphate, sodium chloride, dibasic sodium phosphate dihydrate, and sucrose.

Meanwhile, the ingredients of the Moderna vaccine (pdf) are: mRNA, lipids (SM-102, polyethylene glycol [PEG] 2000 dimyristoyl glycerol [DMG], cholesterol, and 1,2-distearoyl-sn-glycero-3-phosphocholine [DSPC]), tromethamine, tromethamine hydrochloride, acetic acid, sodium acetate, and sucrose.

This week, a doctor from Boston was the first to report an adverse reaction to the Moderna vaccine. The doctor used an EpiPen that was nearby and staffers rushed him to the emergency room which was near the room where he received the vaccination.


... an unexpected spike in allergic reactions to the Pfizer/BioNTech vaccine may prove catastrophic to widespread acceptance unless scientists can figure out what is causing it after the FDA's rushed approval. So in a welcome development, the WSJ reports that according to scientists, the potential culprit causing the allergic reactions to the Pfizer/BioNTech vaccine is the compound polyethylene glycol, also known as PEG.

According to the CDC, at least six severe allergic reactions to the vaccine have been reported so far in the US out of 272,001 doses administered through Dec. 19, while at least two cases of anaphylaxis have also occurred in the UK.

Polyethylene glycol - a polyether compound derived from petroleum with many applications, from industrial manufacturing to medicine - is present in both the Moderna and Pfizer–BioNTech vaccines for SARS-CoV-2 as a PEGylated lipid, which is used as an excipient. Both RNA vaccines consist of Messenger RNA, or mRNA, encased in a bubble of oily molecules called lipids. Proprietary lipid technology is used for each. In both vaccines, the bubbles are coated with a stabilizing molecule of polyethylene glycol.

Scientists have focused in on PEG as a potential suspect even as health authorities say they are still investigating the incidents and plan to study the issue further. The compound is found in other drugs and is known to trigger anaphylaxis on rare occasions.

“Although I think we’re just speculating here…it is known that one of the components that is present in both of the vaccines—polyethylene glycol—can be associated, uncommonly, with allergic reactions,” said Peter Marks, director of the Food and Drug Administration’s Center for Biologics Evaluation and Research, at a Dec. 18 press conference.

“What we’re learning now is that those allergic reactions could be somewhat more common than the highly uncommon that we thought they were because people do get exposed to polyethylene glycol in various pharmaceutical preparations,” Marks added, noting that the FDA also plans to watch the Moderna vaccine rollout “very closely” since both vaccines contain PEG.

In a statement, Pfizer said it “will closely monitor all reports suggestive of serious allergic reactions following vaccination.” The company said its prescribing information includes a warning that “appropriate medical treatment and supervision should always be readily available in case of a rare anaphylactic event following the administration of the vaccine."

As noted above, in both the Pfizer-BioNTech and Moderna vaccines, PEG is part of the fatty envelope that surrounds the messenger RNA, the main ingredient in the vaccine. Once the mRNA gets into cells, it teaches them to make a protein that resembles the spike protein found on the surface of the coronavirus. That induces a specific immune response that shores up the body’s defenses for when it is exposed to the real virus. The PEG-containing fatty envelope helps ensure the mRNA gets across the cell membrane and into the cells.

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