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The Moderna Covid-19 vaccine, like the one made by Pfizer and BioNTech, appears to induce rare anaphylactic reactions in a small number of people who receive the vaccine, new data from the Centers for Disease Control and Prevention suggest.

As of Jan. 19, there have been 15 confirmed cases of anaphylaxis after receipt of Moderna’s vaccine and 45 confirmed cases of anaphylaxis after receipt of the Pfizer vaccine, the CDC said in a statement to STAT. That works out to a rate of 2.1 cases per million doses of the Moderna vaccine and 6.2 cases per million doses of the Pfizer, according to the agency.

Anaphylaxis is a severe allergic reaction that can be life-threatening if not treated quickly.

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“Early monitoring of both the Moderna and the Pfizer-BioNTech Covid-19 vaccines indicate that anaphylaxis following vaccination is a rare event, and although anaphylaxis is serious, it occurs shortly after vaccination (usually within minutes), is readily diagnosed, and effective treatments are available,” the agency said via email.

It noted that the rates at which anaphylaxis is reported following vaccination is likely to change as more vaccine doses are given. In fact, they already have. The first report on U.S. cases of anaphylaxis following administration of the Pfizer vaccine suggested it occurred at a rate of 11.1 cases per million doses given.

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In a report published Friday on anaphylaxis cases among people who received the Moderna vaccine between Dec. 21 and Jan. 10, the CDC detailed 10 cases, all of which occurred in women. During the period of study, more than 4 million doses of the Moderna vaccine were administered.

In Friday’s report, six of the 10 people who developed anaphylaxis were hospitalized and four of them needed to be intubated to assist their breathing. None of the people died, the CDC reported. To date there have been no reports of fatal cases of anaphylaxis associated with Covid vaccines in the United States.

All 10 of the people who developed anaphylaxis were given epinephrine, the drug in EpiPens that is used to combat severe allergic reactions. The CDC has said that those administering Covid vaccines need to be equipped to treat anaphylaxis, including having epinephrine injections on hand.

Anaphylaxis occurred quickly in the people affected, with the median time to the start of symptoms being 7.5 minutes. People who receive Covid-19 vaccines are supposed to be monitored for 15 minutes after the injection, with that period extended to 30 minutes for people with a history of severe allergies or anaphylaxis.

Nine of the 10 people had a history of allergies and five of them had previously experienced an anaphylactic reaction.

This story has been updated with additional data and comment from the CDC. 

  • Moderna vaccine 1/14/21, immediate hard 4”lump at injection site. Week later lump redness & itchy. Otherwise feel fine.

  • Got backed on 1/6. On 1/14 I noticed a nasty rash: red blotches, 1/4 to 1” in diameter, irregular, slightly raised. Dry & patchy skin, over my torso & a little on my arms & thighs. Itchy but not terribly. 2 MDs have said it’s probably the vax – I got Moderna. I still have it & it doesn’t seem to be getting better. 11days! This is getting old.

  • I also had the Moderna vaccine and only mild symptoms for a few days, but a week later felt like I was having an allergy reaction from something I ate, but my arm got hot and red around where the injection was done. Weird!! Taking antihistamines right now.

    • i have had a rash or kind of red skin that is itchy all over my body and it comes and goes , been taking benadril or however you spell it but it not really going away. not sure if I should take more or what

    • I too am having a delayed reaction. Sounds similar, started 8 days after my injection was given. Small bump, then got itchy, red, and hot. I’m taking benadryl and applied lavender and peppermint which seemed to reduce the bump and the irritation.

  • I too had a red itchy warm rash at site of injection 8 days after receiving Moderna vaccine. vsafe app stopped contacting me on day 7 so I could not report this. No other symptoms after vaccine days 1-7. days 8 -11 with rash, contacted my Dr. and was told cold compresses and antihistamine and it worked.

    • So glad to read about your reaction at the site after greater than7 days. Itchy and some rash. Thanks for sharing

    • Hello Brenda,

      Thank you so much for sharing. I also developed a rash 8 exactly days after receiving the Moderna vaccine. (But for the first couple of days I had pain at the injection site and occasional itching during the week but rash.)

      Reading your comment has put me at ease because it looks like your rash went away pretty soon and it will probably only last 8-11 days. I also now know to contact my doctor and that cold compresses and antihistamine will probably give me some relief.

      Also, I see your comment is today. My rash developed today too and I got vaccinated 1/16/2021 at a vaccination site in LA. (at the Hansen dam)

  • I had my vaccine on January 13 and a week after developed a redness, itchy lump on injection site. Is this normal? Since reading on this, it seems I’m not the only one. Any feed back from cdc?

    • Hello Brenda,

      Thank you so much for sharing. I also developed a (warm) bumpy itchy rash 8 exactly days after receiving the Moderna vaccine. (But for the first couple of days I had pain at the injection site and occasional itching during the week but rash.)

      Reading your comment has helped because now I know im not the only one. It also seems like another lady also experienced the same thing.

      Also, I see your comment is today. My rash developed today too and I got vaccinated 1/16/2021 at a vaccination site in LA. (at the Hansen dam)

    • Sorry I mean Eva instead of Brenda since I replied back on this thread. So now that makes 3 of us who have gotten this rash. I am surprised there is not reporting on this no where to be found elsewhere online.

  • Is it possible to get an allergist to respond to these comments? Curious that
    it took a week in most cases for itchy rash to appear. Actually thought it was
    an allergic reaction to a sweater at first.

    • Hi M. I agree. I am 7 days out from first moderna and have a nasty prickly all over my body rash. It is very bad and I have the question of should I get the second shot.

  • Moderna vaccine on 1/22/21. Some pain at injection site. But have splotchy redness below the injection site that isn’t getting better or worse. It measures about 3 x 5 below the site and is splotchy. This is day 2. Should I be concerned????

  • Same as all the others–a week after Moderna injection, large red itchy patch
    on upper arm. Wondering about 2nd shot, especially since more severe effects
    reported 2nd time.

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