How common are allergic reactions to the Moderna vaccine in the US, according to CDC

    How common are allergic reactions to the Moderna vaccine in the US
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    The US Centers for Disease Control and Prevention (CDC) released data on January 22, 2021, on allergic reactions recorded from December 21, 2020 to January 10, 2021 following the first dose of the Moderna coronavirus vaccine.

    According to the CDC, by January 20, 2021, 24,135,690 cases of COVID-19 and 400,306 related deaths had been detected in the United States. On December 18, 2020, the US Food and Drug Administration (FDA) issued an emergency authorization for the two doses of the Moderna vaccine to treat the pandemic. As of January 10, 2021, 4,041,396 people had received the first dose of the vaccine in the United States (2,465,411 women, 1,450,966 men). A total of 1,266  (0.03%) adverse reactions were reported after administration of the vaccine.

    Of these, 108 cases were further investigated as possible severe allergic reactions. Finally, 10 cases of rash were identified, which corresponds to a rate of 2.5 cases per 1,000,000 doses. Anaphylaxis is a severe, life-threatening allergic reaction that occurs within minutes or hours of contact with the allergen.

    All 10 cases involved women with an average age of 47 years (range 31-63). The average time from vaccination to the onset of anaphylaxis was 7.5 minutes (range 1 minute to 45 minutes). In 9 out of 10 cases the rash appeared within 15 minutes of receiving the vaccine while in 1 case the symptoms started after 30 minutes. All 10 patients received epinephrine intramuscularly, according to anaphylactic shock treatment protocols.

    Six patients were hospitalized, of which 5 in the intensive care unit and 4 required endotracheal intubation. The remaining 4 were treated in the emergency department. No one ended up. All cases of rash were successfully treated and recovered. 9 out of 10 people who had an anaphylactic reaction had an individual history of allergy or allergic reactions to drugs (6 people), contrast agents (2 people) and food (1 person). Five people had a previous history of anaphylaxis, but none had been associated with the vaccine. In addition, 43 cases of non-anaphylactic allergic reactions were reported within the first 24 hours after vaccination.

    26 (60%) were classified  as non-severe and the most common symptoms included urticaria, rash, itching in the mouth and throat, shortness of breath and respiratory symptoms. The average age was 43 years (range 22-96) and 39 (91%) cases involved women. The average duration from the administration of the vaccine to the onset of symptoms was 15 minutes (range <1 minute to 24 hours), while in 30 (73%) cases the symptoms appeared within 30 minutes and in 11 cases after the end of 30 minutes. 26 (60%) cases had a previous history of allergies or allergic reactions mainly to food and drugs. 

    In conclusion, the COVID-19 pandemic is in full swing internationally and universal population vaccination is extremely necessary. 

    However, qualified medical personnel in well-equipped areas should evaluate those who come for vaccination with a complete history of allergies and then evaluate those who have been vaccinated for a short period of time for possible signs and symptoms of an allergic reaction. 

    Anyone who has been vaccinated and is experiencing symptoms of an allergic reaction should seek immediate medical attention to be treated appropriately and in a timely manner.

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