Trial Outcomes & Findings for Assessing Safety of Coronavirus Infection (COVID-19) Messenger RNA (mRNA) Vaccine Administration in the Setting of a Previous Adverse Reaction (NCT NCT05212610)
NCT ID: NCT05212610
Last Updated: 2026-03-27
Results Overview
Results reflect the number of participants who had previously received the Pfizer-BioNTech, the Moderna mRNA COVID-19 vaccine, or both, and who had experienced an adverse reaction (AR). An AR would be any symptom reported or objective finding during the 30-minute observation, or any symptom reported at the 7 day follow up. ARs were graded using the FDA Guidance for Industry Toxicity Grading Scale for Healthy Adult and Adolescent Volunteers Enrolled in Preventive Vaccine Clinical Trials, which utilized the following grades: Grade 1 = Mild Grade 2 = Moderate Grade 3 = Severe Grade 4 = Life-threatening Grade 5 = Death
COMPLETED
PHASE4
137 participants
up to approximately 7 days after the vaccine is given
2026-03-27
Participant Flow
137 participants were consented. 18 participants withdrew prior to vaccination, 5 participants screen-failed, 1 participant was withdrawn by the investigator, and 10 participants were lost to follow-up. Participants chose which of the two vaccines (Pfizer-BioNTech or Moderna) they wanted to receive for the trial.
Participant milestones
| Measure |
Pfizer-BioNTech mRNA COVID-19 Vaccine
Subject will receive an initial or additional dose of the Pfizer-BioNTech (Comirnaty) mRNA COVID-19 vaccine
Pfizer-BioNTech mRNA COVID-19 vaccine: Participants will receive an initial or additional dose of a highly protective COVID-19 mRNA vaccine for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus in an environment where the investigators and staff are experienced in the care of patients with allergic reactions.
|
Moderna mRNA COVID-19 Vaccine
Subject will receive an initial or additional dose of the Moderna mRNA COVID-19 vaccine
Moderna mRNA COVID-19 vaccine: Participants will receive an initial or additional dose of a highly protective COVID-19 mRNA vaccine for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus in an environment where the investigators and staff are experienced in the care of patients with allergic reactions.
|
|---|---|---|
|
Overall Study
STARTED
|
97
|
6
|
|
Overall Study
COMPLETED
|
95
|
6
|
|
Overall Study
NOT COMPLETED
|
2
|
0
|
Reasons for withdrawal
| Measure |
Pfizer-BioNTech mRNA COVID-19 Vaccine
Subject will receive an initial or additional dose of the Pfizer-BioNTech (Comirnaty) mRNA COVID-19 vaccine
Pfizer-BioNTech mRNA COVID-19 vaccine: Participants will receive an initial or additional dose of a highly protective COVID-19 mRNA vaccine for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus in an environment where the investigators and staff are experienced in the care of patients with allergic reactions.
|
Moderna mRNA COVID-19 Vaccine
Subject will receive an initial or additional dose of the Moderna mRNA COVID-19 vaccine
Moderna mRNA COVID-19 vaccine: Participants will receive an initial or additional dose of a highly protective COVID-19 mRNA vaccine for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus in an environment where the investigators and staff are experienced in the care of patients with allergic reactions.
|
|---|---|---|
|
Overall Study
Lost to Follow-up
|
2
|
0
|
Baseline Characteristics
Assessing Safety of Coronavirus Infection (COVID-19) Messenger RNA (mRNA) Vaccine Administration in the Setting of a Previous Adverse Reaction
Baseline characteristics by cohort
| Measure |
Moderna mRNA COVID-19 Vaccine
n=6 Participants
Subject will receive an initial or additional dose of the Moderna mRNA COVID-19 vaccine
Moderna mRNA COVID-19 vaccine: Participants will receive an initial or additional dose of a highly protective COVID-19 mRNA vaccine for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus in an environment where the investigators and staff are experienced in the care of patients with allergic reactions.
|
Total
n=103 Participants
Total of all reporting groups
|
Pfizer-BioNTech mRNA COVID-19 Vaccine
n=97 Participants
Subject will receive an initial or additional dose of the Pfizer-BioNTech (Comirnaty) mRNA COVID-19 vaccine
Pfizer-BioNTech mRNA COVID-19 vaccine: Participants will receive an initial or additional dose of a highly protective COVID-19 mRNA vaccine for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus in an environment where the investigators and staff are experienced in the care of patients with allergic reactions.
|
|---|---|---|---|
|
Age, Continuous
|
33.5 years
STANDARD_DEVIATION 9.3 • n=62 Participants
|
41.8 years
STANDARD_DEVIATION 15.5 • n=123 Participants
|
43.2 years
STANDARD_DEVIATION 15.7 • n=56 Participants
|
|
Sex/Gender, Customized
Female
|
5 Participants
n=62 Participants
|
69 Participants
n=123 Participants
|
64 Participants
n=56 Participants
|
|
Sex/Gender, Customized
Male
|
1 Participants
n=62 Participants
|
32 Participants
n=123 Participants
|
31 Participants
n=56 Participants
|
|
Sex/Gender, Customized
Undisclosed
|
0 Participants
n=62 Participants
|
2 Participants
n=123 Participants
|
2 Participants
n=56 Participants
|
|
Ethnicity (NIH/OMB)
Hispanic or Latino
|
0 Participants
n=62 Participants
|
4 Participants
n=123 Participants
|
4 Participants
n=56 Participants
|
|
Ethnicity (NIH/OMB)
Not Hispanic or Latino
|
5 Participants
n=62 Participants
|
97 Participants
n=123 Participants
|
92 Participants
n=56 Participants
|
|
Ethnicity (NIH/OMB)
Unknown or Not Reported
|
1 Participants
n=62 Participants
|
2 Participants
n=123 Participants
|
1 Participants
n=56 Participants
|
|
Race/Ethnicity, Customized
Asian
|
1 Participants
n=62 Participants
|
16 Participants
n=123 Participants
|
15 Participants
n=56 Participants
|
|
Race/Ethnicity, Customized
African American
|
1 Participants
n=62 Participants
|
5 Participants
n=123 Participants
|
4 Participants
n=56 Participants
|
|
Race/Ethnicity, Customized
White
|
1 Participants
n=62 Participants
|
72 Participants
n=123 Participants
|
71 Participants
n=56 Participants
|
|
Race/Ethnicity, Customized
More Than One Race
|
0 Participants
n=62 Participants
|
1 Participants
n=123 Participants
|
1 Participants
n=56 Participants
|
|
Race/Ethnicity, Customized
Other
|
0 Participants
n=62 Participants
|
4 Participants
n=123 Participants
|
4 Participants
n=56 Participants
|
|
Race/Ethnicity, Customized
Unknown
|
3 Participants
n=62 Participants
|
5 Participants
n=123 Participants
|
2 Participants
n=56 Participants
|
|
Region of Enrollment
United States
|
6 Participants
n=62 Participants
|
103 Participants
n=123 Participants
|
97 Participants
n=56 Participants
|
|
Previous COVID-19 vaccine status
Single dose
|
3 Participants
n=62 Participants
|
8 Participants
n=123 Participants
|
5 Participants
n=56 Participants
|
|
Previous COVID-19 vaccine status
Two doses
|
2 Participants
n=62 Participants
|
11 Participants
n=123 Participants
|
9 Participants
n=56 Participants
|
|
Previous COVID-19 vaccine status
At least 1 booster dose
|
1 Participants
n=62 Participants
|
84 Participants
n=123 Participants
|
83 Participants
n=56 Participants
|
|
Long COVID diagnosis
Physician diagnosis
|
2 Participants
n=62 Participants
|
15 Participants
n=123 Participants
|
13 Participants
n=56 Participants
|
|
Long COVID diagnosis
Self-diagnosis
|
2 Participants
n=62 Participants
|
5 Participants
n=123 Participants
|
3 Participants
n=56 Participants
|
|
Long COVID diagnosis
No diagnosis
|
2 Participants
n=62 Participants
|
83 Participants
n=123 Participants
|
81 Participants
n=56 Participants
|
PRIMARY outcome
Timeframe: up to approximately 7 days after the vaccine is givenPopulation: Data was collected at the 7-day follow-up. 2 participants were lost to follow up, so no data was collected for them.
Results reflect the number of participants who had previously received the Pfizer-BioNTech, the Moderna mRNA COVID-19 vaccine, or both, and who had experienced an adverse reaction (AR). An AR would be any symptom reported or objective finding during the 30-minute observation, or any symptom reported at the 7 day follow up. ARs were graded using the FDA Guidance for Industry Toxicity Grading Scale for Healthy Adult and Adolescent Volunteers Enrolled in Preventive Vaccine Clinical Trials, which utilized the following grades: Grade 1 = Mild Grade 2 = Moderate Grade 3 = Severe Grade 4 = Life-threatening Grade 5 = Death
Outcome measures
| Measure |
Pfizer-BioNTech mRNA COVID-19 Vaccine
n=95 Participants
Subject will receive an initial or additional dose of the Pfizer-BioNTech (Comirnaty) mRNA COVID-19 vaccine
Pfizer-BioNTech mRNA COVID-19 vaccine: Participants will receive an initial or additional dose of a highly protective COVID-19 mRNA vaccine for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus in an environment where the investigators and staff are experienced in the care of patients with allergic reactions.
|
Moderna mRNA COVID-19 Vaccine
n=6 Participants
Subject will receive an initial or additional dose of the Moderna mRNA COVID-19 vaccine
Moderna mRNA COVID-19 vaccine: Participants will receive an initial or additional dose of a highly protective COVID-19 mRNA vaccine for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus in an environment where the investigators and staff are experienced in the care of patients with allergic reactions.
|
|---|---|---|
|
Participants Who Had a Reaction to an Initial or Additional Dose of the Pfizer-BioNTech or Moderna COVID-19 mRNA Vaccine, or Who Had Long COVID
Grade 1
|
71 Participants
|
2 Participants
|
|
Participants Who Had a Reaction to an Initial or Additional Dose of the Pfizer-BioNTech or Moderna COVID-19 mRNA Vaccine, or Who Had Long COVID
Grade 2
|
1 Participants
|
1 Participants
|
|
Participants Who Had a Reaction to an Initial or Additional Dose of the Pfizer-BioNTech or Moderna COVID-19 mRNA Vaccine, or Who Had Long COVID
Grades 3-5
|
0 Participants
|
0 Participants
|
PRIMARY outcome
Timeframe: up to approximately 7 days after the vaccine is givenPopulation: Data was collected at the 7-day follow-up. 2 participants were lost to follow up, so no data was collected for them.
The safety of administering an initial or additional dose will be determined by using the grading of systemic allergic reactions will be based on a scale of 1 (mild reaction) to 5 (severe reaction, including death) according to criteria set forth in the Consortium of Food Allergy Research (CoFAR) grading scale (version 3.0) modified for adults as well as the Brighton Collaboration to grade the diagnostic certainty of anaphylaxis. Results reflect the number of participants who received an initial dose or were revaccinated during the trial, and experienced related acute allergic reaction adverse event, and what the CoFAR severity for the events was. Events were deemed to be allergic if symptoms were consistent with an IgE-reaction and symptom onset began within 1 hour of vaccination.
Outcome measures
| Measure |
Pfizer-BioNTech mRNA COVID-19 Vaccine
n=95 Participants
Subject will receive an initial or additional dose of the Pfizer-BioNTech (Comirnaty) mRNA COVID-19 vaccine
Pfizer-BioNTech mRNA COVID-19 vaccine: Participants will receive an initial or additional dose of a highly protective COVID-19 mRNA vaccine for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus in an environment where the investigators and staff are experienced in the care of patients with allergic reactions.
|
Moderna mRNA COVID-19 Vaccine
n=6 Participants
Subject will receive an initial or additional dose of the Moderna mRNA COVID-19 vaccine
Moderna mRNA COVID-19 vaccine: Participants will receive an initial or additional dose of a highly protective COVID-19 mRNA vaccine for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus in an environment where the investigators and staff are experienced in the care of patients with allergic reactions.
|
|---|---|---|
|
Number of Participants With Treatment-related Allergic Reaction Adverse Events
CoFAR Severity 1
|
3 Participants
|
1 Participants
|
|
Number of Participants With Treatment-related Allergic Reaction Adverse Events
CoFAR Severity 2
|
1 Participants
|
0 Participants
|
|
Number of Participants With Treatment-related Allergic Reaction Adverse Events
CoFAR Severity 3
|
0 Participants
|
0 Participants
|
|
Number of Participants With Treatment-related Allergic Reaction Adverse Events
CoFAR Severity 4
|
0 Participants
|
0 Participants
|
|
Number of Participants With Treatment-related Allergic Reaction Adverse Events
CoFAR Severity 5
|
0 Participants
|
0 Participants
|
SECONDARY outcome
Timeframe: up to approximately 7 days after the vaccine is givenPopulation: Data was collected at the 7-day follow-up. 2 participants were lost to follow up, so no data was collected for them.
Results reflect the number of participants who experienced a non-allergic clinical adverse reaction (AR). A non-allergic clinical AR was determined by non-allergic symptomatology and time frame from when the participant received a vaccine. Nonallergic ARs were symptoms that were inconsistent with an IgE-mechanism or had an onset greater than 1 hour following vaccination. ARs were graded using the FDA Guidance for Industry Toxicity Grading Scale for Healthy Adult and Adolescent Volunteers Enrolled in Preventive Vaccine Clinical Trials, which utilized the following grades: Grade 1 = Mild Grade 2 = Moderate Grade 3 = Severe Grade 4 = Life-threatening Grade 5 = Death
Outcome measures
| Measure |
Pfizer-BioNTech mRNA COVID-19 Vaccine
n=95 Participants
Subject will receive an initial or additional dose of the Pfizer-BioNTech (Comirnaty) mRNA COVID-19 vaccine
Pfizer-BioNTech mRNA COVID-19 vaccine: Participants will receive an initial or additional dose of a highly protective COVID-19 mRNA vaccine for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus in an environment where the investigators and staff are experienced in the care of patients with allergic reactions.
|
Moderna mRNA COVID-19 Vaccine
n=6 Participants
Subject will receive an initial or additional dose of the Moderna mRNA COVID-19 vaccine
Moderna mRNA COVID-19 vaccine: Participants will receive an initial or additional dose of a highly protective COVID-19 mRNA vaccine for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus in an environment where the investigators and staff are experienced in the care of patients with allergic reactions.
|
|---|---|---|
|
Number of Non-allergic Clinical Adverse Reactions
Grade 1
|
68 Participants
|
1 Participants
|
|
Number of Non-allergic Clinical Adverse Reactions
Grade 2
|
0 Participants
|
1 Participants
|
|
Number of Non-allergic Clinical Adverse Reactions
Grades 3-5
|
0 Participants
|
0 Participants
|
Adverse Events
Pfizer-BioNTech mRNA COVID-19 Vaccine
Moderna mRNA COVID-19 Vaccine
Serious adverse events
Adverse event data not reported
Other adverse events
| Measure |
Pfizer-BioNTech mRNA COVID-19 Vaccine
n=97 participants at risk
Subject will receive an initial or additional dose of the Pfizer-BioNTech (Comirnaty) mRNA COVID-19 vaccine
Pfizer-BioNTech mRNA COVID-19 vaccine: Participants will receive an initial or additional dose of a highly protective COVID-19 mRNA vaccine for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus in an environment where the investigators and staff are experienced in the care of patients with allergic reactions.
|
Moderna mRNA COVID-19 Vaccine
n=6 participants at risk
Subject will receive an initial or additional dose of the Moderna mRNA COVID-19 vaccine
Moderna mRNA COVID-19 vaccine: Participants will receive an initial or additional dose of a highly protective COVID-19 mRNA vaccine for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus in an environment where the investigators and staff are experienced in the care of patients with allergic reactions.
|
|---|---|---|
|
General disorders
Fatigue
|
33.0%
32/97 • up to approximately 7 days after the vaccine is given
|
33.3%
2/6 • up to approximately 7 days after the vaccine is given
|
|
Musculoskeletal and connective tissue disorders
Muscle Pain
|
29.9%
29/97 • up to approximately 7 days after the vaccine is given
|
0.00%
0/6 • up to approximately 7 days after the vaccine is given
|
|
General disorders
Headache
|
29.9%
29/97 • up to approximately 7 days after the vaccine is given
|
16.7%
1/6 • up to approximately 7 days after the vaccine is given
|
|
Gastrointestinal disorders
Diarrhea
|
1.0%
1/97 • up to approximately 7 days after the vaccine is given
|
16.7%
1/6 • up to approximately 7 days after the vaccine is given
|
|
Skin and subcutaneous tissue disorders
Lip swelling
|
1.0%
1/97 • up to approximately 7 days after the vaccine is given
|
0.00%
0/6 • up to approximately 7 days after the vaccine is given
|
|
Skin and subcutaneous tissue disorders
Pruritis
|
2.1%
2/97 • up to approximately 7 days after the vaccine is given
|
16.7%
1/6 • up to approximately 7 days after the vaccine is given
|
|
General disorders
Migraine
|
0.00%
0/97 • up to approximately 7 days after the vaccine is given
|
16.7%
1/6 • up to approximately 7 days after the vaccine is given
|
Additional Information
Results disclosure agreements
- Principal investigator is a sponsor employee
- Publication restrictions are in place