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Allergic Reactions to mRNA Covid Vaccines?

Morbidity and Mortality Weekly Review (MMWR), a publication, of the CDC, reported on 21 cases of anaphylaxis between Dec 14-23rd following vaccination with the Pfizer vaccine.  Anaphylaxis can occur after any vaccination and these are cases from the first use of the Pfizer vaccine after their FDA Emergency Use Authorization was granted.  There were 1.9 million Americans who received the Pfizer vaccine during that period, for an incidence of 11.1 cases of anaphylaxis per million vaccinated.  These reports were sent to the CDC through multiple safety reporting methods, and after an initial review there were 175 cases that needed to be carefully assessed and only 21 cases of anaphylaxis were found. The diagnosis of anaphylaxis was based on a worldwide scientific system of classification of anaphylaxis.  17 of the patients had a history of allergies and 7 of the patients had a history of a prior anaphylactic episode. 

The median age of the patients was 40.  Ninety % were women.  The median interval to developing symptoms was 13 minutes with 14% occurring after 30 minutes.  All patients were treated with epinephrine and recovered.  One patient was lost to followup.  81% of these patients had a history of allergies: drugs, medical products, foods, insect stings.  These cases were spread geographically and none received vaccines from the same lot numbers.   

After review there were 83 cases of non-anaphylactic allergic reactions: itching, rash, itchy and scratchy symptoms in the throat, and mild respiratory symptoms.  67% of these patients had a past history of allergic symptoms. The remainder of the cases reviewed were non-allergic, i.e. like vasovagal syncope (fainting).

More below. 


I watched the CDC broadcast on vaccine allergic reactions several weeks ago, mainly because  I have multiple allergies.  These are their recommendations:

1.  Any patient who has anaphylaxis to either the Moderna or Pfizer vaccine, should NOT be vaccinated again with those vaccines.

2.  Any patient who has a history of anaphylaxis to a prior vaccine (i.e. influenza etc) or to an IV drug should consult an allergist and their risk vs benefit ratio to vaccination assessed.

3.  Any patient with allergies to foods, animal danders, insect stings, meds (given orally), eggs, gelatin, and/or positive family history may receive the vaccines. 

Vaccination sites should screen patients for allergies, have medical resuscitation equipment and epinephrine in prefilled syringes available, and observe all patients with allergies for 30 minutes post vaccination, instead of 15 min.  Data from the Moderna vaccine experience will be reported soon.  Only one case of anaphylaxis was reported early as far as is mentioned in the press.

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