Can people who reacted badly to a COVID shot still get vaccinated?
NCT ID NCT05028257
First seen Sep 17, 2026 · Last updated Sep 18, 2026 · Updated 1 time
Summary
Some people have a severe allergic reaction, called anaphylaxis, after a COVID-19 vaccine. This study checks whether those people can safely receive another dose. Researchers also run allergy tests to find out which vaccine ingredients, such as PEG2000 or PS80, might cause the reactions. The goal is to help doctors decide who can continue vaccination and who should not.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- COVID-19 vaccines from Pfizer-BioNTech, Moderna, AstraZeneca, or Janssen
- What this could lead to
- If the approach works, doctors could offer a clear path for people with a history of severe vaccine reactions to complete COVID-19 vaccination safely.
- What could go wrong
- This is a small study of 117 people, and results may not apply to everyone. Some participants could have another allergic reaction during testing or revaccination.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
-
Phase 3
Large-scale testing in a bigger group. Usually the last step before a treatment can be approved.
- Participants
-
117 people
The number who actually took part.
- Started
-
Sep 2021
- Finished
-
May 2023
- Lead sponsor
-
Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
-
18 years and older
- Sex
-
Anyone
- Healthy volunteers
-
Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: * Age ≥ 18 years * Anaphylactic reaction to a COVID-19 vaccine administered by Pfizer-BioNtech or Janssen or Vaxzevria or Moderna, at least 3 weeks old at the time of the allergology consultation. An anaphylactic reaction is defined as the occurrence of any of the following systemic manifestations within a few hours of administration of a COVID-19 vaccine: * skin rash with urticaria and/or angiodema, * and/or associated with respiratory signs (dyspnea, bronchospasm, desaturation), and/or digestive disorders (intense abdominal pain, diarrhea, vomiting, nausea), and/or neurological disorders (loss of consciousness, feeling of malaise), and/or hypotension, tachycardia. * Affiliation to a Social Security system * Signature of the informed consent * Stop taking antihistamines at least 3 days before skin allergy tests are performed Exclusion Criteria: * Other non-anaphylactic systemic reactions after administration of COVID-19 mRNA vaccine (serum sickness, vasculitis, Guillain-Barré syndrome) * Pregnancy and lactation * Disorders of hemostasis or severe bleeding considered a contraindication to intramuscular injection
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
-
Tenon Hospital APHP dermatology and allergology department
Paris, 75020, France
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