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The Centers for Disease Control and Prevention on Sunday said people who have experienced severe reactions to prior vaccines or injectable drugs can still get the Pfizer/BioNTech vaccine for Covid-19, but should discuss the risks with their doctors and be monitored for 30 minutes afterward.

The guidance is a shift from a prior proposal laid out Saturday that would have recommended against vaccination for that group of people. During a webinar with physicians, CDC officials said patients with a history of severe reactions should take precautions because of two documented cases of anaphylaxis in British health care workers who received the Pfizer/BioNTech vaccine.


“People that do report those types of anaphylactic reactions to other vaccines or injectables — they can still get the vaccine, but they should be counseled about the unknown risks of developing a severe allergic reaction and balance these risks against the benefit of vaccination,” said Sarah Mbaeyi, a medical officer with the CDC’s National Center for Immunization and Respiratory Diseases.

Mbaeyi said people should discuss a prior allergic reaction with their doctors to help assess whether it was truly caused by an injectable medicine and constituted a severe reaction. The specific reaction providers are trying to avoid is anaphylaxis, which is life-threatening and causes symptoms such as dizziness, difficulty breathing, wheezing, and a fast heart rate.



Mbaeyi said people with other types of allergies — to food, latex, pollen or other substances — do not have to take special precautions and are recommended to receive the Pfizer/BioNTech vaccine.

The guidance differs from instructions issued by British regulators, who are recommending against vaccination for people who have experienced anaphylaxis due to allergies to food or medicine. The cases of anaphylaxis in that country are still under investigation, as the cause remains unknown.

In the U.S., regulators are only recommending against vaccination for people with an allergy to a specific component for Pfizer/BioNTech vaccine. The recommendation is contained in a fact sheet issued by the Food and Drug Administration, which granted an emergency use authorization to the Pfizer/BioNTech product late Friday.

Severe allergic reactions to vaccines are extremely rare and were also rare during the Pfizer/BioNTech trial, which excluded people with a history of anaphylaxis. The FDA has released data indicating .63% of participants who received the vaccine experienced serious adverse reactions, compared to .51% of people who received a placebo.

During the CDC call on Sunday, officials said they had received multiple questions about allergic reactions to the vaccine and the components within it. Amanda Cohn, an official with the CDC’s Covid-19 vaccine planning unit, said the vaccine consists of messenger RNA and four lipid nanoparticles and that there are no preservatives or other ingredients in the vaccine.

She said people could be allergic to a part of the lipid nanoparticle known as polyethylene glycol, or PEG, which is a component in other injectable medicines. “That is partially the reason for the extra precautions for persons who have (had reactions) to other injectables, Cohn said. “We are being abundantly cautious about this question related to allergic reactions. We don’t want people who have mild allergic reactions to be concerned about getting vaccinated.”

The FDA has said it will monitor any allergic reactions closely as the vaccines roll out and may need to modify its guidance going forward. CDC officials made the same promise on Sunday as the first doses were shipped across the U.S.

“We will learn a lot more as we follow the use of this vaccine very carefully,” Cohn said. “We know that these vaccines have the potential to end this pandemic and we know that it is critical for health care providers to have confidence that these vaccines are very safe.”

  • First Glitches Emerge In COVID-Vax Rollout; Alaska Health Worker Suffers ‘Serious Allergic Reaction’
    A healthcare worker in Alaska was hospitalized on Tuesday with a ‘serious allergic reaction’ after receiving Pfizer’s COVID-19 vaccine, according to the New York Times.


    The person, who had no known drug allergies, was still in the hospital on Wednesday morning under observation, according to the report. It is unknown whether they suffer from any other types of allergies. The Alaska resident’s reatcion was reportedly similar to anaphylactic reactions two heal workers in Britain experience after receiving the Pfizer-BioNTech vaccine last week – both of whom have recovered. Of note, they both had a history of severe allergies. One, a 49-year-old woman, is allergic to eggs (which Pfizer says are not in their vaccine). The other, a 40-year-old woman is allergic to several different medications. Both routinely carry EpiPenn-like devices in case of reactions.

    After the workers in Britain fell ill, authorities there initially warned against giving the vaccines to anyone with a history of severe allergic reactions. They later clarified their concerns, changing the wording from “severe allergic reactions” to specify that the vaccine should not be given to anyone who has ever had an anaphylactic reaction to a food, medicine or vaccine. That type of reaction to a vaccine is “very rare,” they said. -NYT

    No serious adverse effects were reported during Pfizer’s US trial involving over 40,000 participants, aside from aches, fevers and other ‘minor’ side effects.

    Headaches all around

    As Bloomberg notes, the first hiccups in the distribution of Pfizer’s vaccine are just beginning – including a holdup on the delivery of 3,900 shots to two states, and the announcement that roughly 900,000 fewer doses would be delivered next week than were shipped this week.

    Four delivery trays of the Pfizer-BioNTech SE vaccine were pulled back from delivery to California and Alabama this week and sent back to the company because they were colder than anticipated, according to Gustave Perna, the army general who serves as Operation Warp Speed’s chief operations officer.

    Each of the trays can likely be used to vaccinate 975 people. Pfizer has said its formula needs to be stored at 70 degrees below zero Celsius, the equivalent of negative 94 degrees below zero Fahrenheit. These trays were found to be much colder, according to Perna. -Bloomberg

    “We were taking no chances,” said Perna during a Wednesday news briefing.

    The Pfizer doses are shipped in temperature-controlled containers developed by company engineers, each of which are equipped with GPS tracking “for continuous, real-time location and temperature monitoring,” per the company.

    Meanwhile, roughly 2 million doses of the Pfizer vaccine will ship next week in the US, which is 900K less than the 2.9 million doses available this week. Health and Human Services secretary Alex Azar acknowledge the production hiccups, saying “As you know, they ended up coming short by half of what they thought they’d be able to produce and what they’d announced they’d be able to produce” in 2020.

    “They’re right now producing at their maximum capacity to deliver on the 100 million that is in the first tranche of the contract with us, and we’re providing manufacturing support,” Azar added.

    And on Tuesday, Florida Governor Ron DeSantis said that shipments of hundreds of thousands of doses were held up due to “a production issue with Pfizer.”

    The company pushed back, with spokeswoman Amy Rose saying that the company “has not had any production issues with our COVID-19 vaccine, and no shipments containing the vaccine are on hold or delayed,” adding “We are continuing to dispatch our orders to the locations specified by the U.S. government.”

  • 2 of my 4 children had severe reactions to the Pertussis vaccine. My oldest daughter had her leg swell to twice it’s size and daughter #2 had a mild seizure. Our pediatrician stopped giving them that vaccine and said not to give it to any more children that we may have in the future. We had 2 more children and they have never received the Pertussis vaccine.

    My 2 oldest daughters are now 36 and 34. Can this vaccine affect them? Also, my youngest (my only son) has asthma and is highly allergic to shellfish. What about him?

    This concerned mom has a lot of questions!

  • I have had moderate anaphylactic reactions to injectable iodine, and to the iodine in shellfish. I have also had moderate anaphylactic reactions to oral sulfa drugs, as well as high temperature after oral administration of the drug called Macrobid.
    Good news: I have had no reactions to any vaccines, including annual flu and a long-term pneumonia vaccine for seniors. I do not use an epi-pen.
    Question: Should I take a 50mg dose of oral prednisone within 12 hours prior to receiving an emergency-approved COVID vaccine. Will doing so affect the efficacy of the vaccine?

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