Infrequent complications
June 14, 2026
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June 14, 2026
Infrequent complications
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Dr John Campbell Episodes Around June 14, 2026
Episode 128 of 364 — walk the feed in the order it was published.
23:30This episodeInfrequent complications
Summary
Changes of ECG parameters after BNT162b2 vaccine in the senior high school students
https://pubmed.ncbi.nlm.nih.gov/36602621/
Full text link
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9813456/
Data collected, December 2021
Published, January 2023
Aims
Determine the ECG parameter change
Determine efficacy of ECG screening after the second dose of BNT162b2
In cooperation with the school vaccination system of Taipei City government (Taiwan)
N = 4,928 (mostly male)
12 to 18 year old
Before and after 12 lead ECGs
Three follow up 12 lead ECGs
ECGs read by by pediatric cardiologists
Serial comparisons of ECGs and questionnaire survey
Heart rate increased significantly after the vaccine,
(mean increase of 2.6 beats per minute)
QRS duration and QT interval decreased significantly after the vaccine with increasing heart rate
763 (17.1%) had at least one cardiac symptom after the second vaccine dose.
After the first dose, 209 (5.7%) had at least one cardiac symptom
Cardiac symptoms
Chest pain
Palpitations
Dizziness or syncope
Depolarization and repolarization parameters
All 4 cardiac symptoms significantly higher after the second dose of BNT162b2 vaccine (p less than 0.001)
N = 4,928
Abnormal ECGs were obtained in 51 (1.0%)
31 students were asymptomatic
ST – T changes, 37
Premature ventricular contractions, 4
Sinus bradycardia, 2
Atrial tachycardia, 1
Incomplete right bundle branch block, 3
Abnormal QRS, 2
Prolonged QT, 2
4 judged to have significant arrhythmia
1 was diagnosed with mild myocarditis
10, suspected pericarditis
All of these symptoms improved over time
Asymptomatic at one month
No covid in Taiwan at this time.
Conclusion
Cardiac symptoms are common after the second dose of BNT162b2 vaccine
Incidences of significant arrhythmias and myocarditis are 0.1%
One in a thousand
Rotavirus vaccine Rotashield, (1999)
https://www.cdc.gov/vaccines/vpd-vac/rotavirus/vac-rotashield-historical.htm
1 to 2 serious events per 10,000 vaccinees
(Intussusception)
Vaccine withdrawn
From the authors
BNT162b2 has a better safety profile than mRNA-1273 Moderna