Table 7.
Details of each study identified by systematic review which met the inclusion criteria
| First author and citation | Study design | Study period | Vaccine | Population | No. cases in exposed to mRNA vaccine | Diagnostic criteria | Percentage of cases who were male | Age of cases | Vaccine dose | Risk/Rate Ratio (RR) (95% CI) | Incidence (95% CI) | |
| 1 | Barda48 | Cohort with unvaccinated comparator | December 2020 - May 2021 | Comirnaty | Israel, electronic health records | Myocarditis n=21; Pericarditis n=27 | NR | NR | NR | Myocarditis=3.24 (1.55 to 12.44); Pericarditis=1.27 (0.68 to 2.31) | NC | |
| 2 | Chouchana25 | Analysis of VigiBase spontaneous reports | Vaccine launch - end June 2021 | mRNA COVID vaccine | Vigibase reports | Myocarditis n=1241; Pericarditis n=851; Myo-pericarditis n=167; Pleuro-pericarditis n=18 |
68.30% | Median 33 (21–54) years | NR | NC | NC | |
| 3 | Chua49 | Population cohort study | 14 June 2021 - 4 September 2021 | Comirnaty | Hong Kong adolescents, electronic health records | n=33 cases (myocarditis/ pericarditis) | 87.88% | Median 15.25 years | 81.82% followed 2nd dose | NC | Overall=18.52 (95% CI 11.67 to 29.01); Males=32.29 (95% CI 22.78 to 45.4); Females=4.53 (95% CI 1.76 to 11.11) |
|
| 4 | Das50 | Cross sectional study of 25 children aged 12–18 years diagnosed with probable myopericarditis following COVID-19 mRNA vaccination | 10 May 2021 - 20 June 2021 | Comirnaty | Adolescents presenting at 8 US centres | n=25 (myo-pericarditis) | 88% | Range 12–17 years | 88% followed 2nd dose | NC | NC | |
| 5 | Diaz51 | Retrospective cohort | Vaccine launch - 25 May 2021 | mrNA COVID vaccine plus AZ vaccine | 40 US hospitals, electronic health records | Myocarditis n=20; pericarditis n=35 | Myocarditis75%; pericarditis 73% | Myocarditis cases median 36 (26.3–48.3) years; Pericarditis cases median 59 46–69) years | NR | NC | NC | |
| 6 | Eggebrecht52 | Cohort | 27 December 2020 - 3 September 2021 | All COVID vaccines | 113 patients at cardiology unit | Comirnaty cases n=85; Spikevax n=13 | 56% | Average age 45.9 years, 95% CI 43.2 to 48.7 | 57% followed 2nd dose | NC | NC | |
| 7 | Farahmand26 | Cohort | 3 August 2020 – 21 May 2021 | All COVID vaccines | Patients and employees of the Beth Israel Deaconess Medical Center (BIDMC), electronic health records |
n=7 | 50.00% | Participants aged 25 years and older | NR | Age adjusted rate ratio=9.7 (p=0.04) | NC | |
| 8 | Foltran53 | Analysis of VigiBase spontaneous reports | 1 January - 14 September 2021 | mRNA COVID vaccines | Vigibase reports for adolescents aged 12–17 years | n=242 cases (pericarditis and/or myocarditis) | 85% | Mean 15.8 (±1.4 years) | 1 or 2 doses | NC | NC | |
| 9 | Fronza54 | Retrospective cohort | December 2019 – November 2021 | All COVID vaccines | Consecutive adults referred to a tertiary hospital network for MRI | Spikevax n=12; Comirnaty n=9 | 81% | Mean (SD) 31 (14) years | 17 followed 2nd dose | NC | NC | |
| 10 | Gargano55 | Analysis of VAERS spontaneous reports | 29 December 2020 – 11 June 2021 | mRNA COVID vaccines | VAERS reports | n=1226 | 76.2% of 1212 cases where sex available | Median age 26 years (range 12–94 years) | 76% followed 2nd dose (where dose was reported) | NC | NC | |
| 11 | Golino56 | Observational study | June - August 2021 | mRNA COVID vaccines | Hospital admissions, University of Insubria, Varese, Italy | n=12 (myo-pericarditis) | 33% of cases were young males | Males aged 29 (±12) years | NR | NC | NC | |
| 12 | Hajjo39 | VAERS analysis | Vaccine launch – 2 September 2021 | All COVID vaccines | VAERS reports | Myocarditis=1579; Pericarditis=1063 |
myo=77%, peri=65% | Range 6–80+years | 1–3 doses | NC | NC | |
| 13 | Hause12 | VAERS & V-Safe analysis | 14 December 2020 – 16 July 2021 | Comirnaty | VAERS and V-Safe reports for adolescents | n=379 (myocarditis) | NR | NR | NR | NC | NC | |
| 14 | Husby57 | Population-based cohort study | 1 October 2020 – 5 October 2021 | All COVID vaccines | Danish health records databases (all individuals in Denmark aged 12 and over) | Comirnaty n=48; Spikevax n=21 |
NR | NR | NR | NC | Absolute rate within 28 days of vaccination: Overall=1.7 (95% CI 1.3 to 2.2) per 100 000 vaccinated individuals. Comirnaty=1.4 (1.0 to 1.8) per 100 000 Spikevax=4.2 (2.6 to 6.4) per 100 000 |
|
| 15 | Jain27 | Retrospective multicentre study | March 2021 – June 2021 | mRNA COVID vaccines | Patients<21 years presenting to 16 US hospitals | Comirnaty n=59; Spikevax n=4 |
92% | Mean 15.6±1.8 years (range 12–20 years) |
62 cases followed 2nd dose | NC | NC | |
| 16 | Kerneis58 | Vigibase analysis | 1967–7 May 2021 | All COVID vaccines | Vigibase reports | Comirnaty n=151; Spikevax n=51 | 63.90% | Median 35 (IQR 25–50) years | NR | NC | NC | |
| 17 | Klein28 | Vaccine Safety Datalink analysis | 14 December 2020 – 26 June 2021 | mRNA COVID vaccines | Electronic health records | n=87 (myocarditis/ pericarditis) | 85% | Range 12–39 years | NR | NC | NC | |
| 18 | Knowlton59 | Cohort / Case-crossover | 15 December 2020 – 15 June 2021 | All COVID vaccines | Adult patients presenting at Intermountain Healthcare | Comirnaty n=5; Spikevax n=15 |
71.40% | Median (IQR) 56 (28–70) years | NR | Within 60 days RR=1.63 (95% CI 0.95 to 2.71); Within 30 days RR=2.05 (95% CI 1.17 to 3.48) |
NC | |
| 19 | Kravchenko60 | Retrospective cohort | NR | mRNA COVID-19 vaccines | All patients referred for cardiac MRI to the Department of Diagnostic and Interventional Radiology, University Hospital Bonn | Comirnaty n=19; Spikevax n=1 |
60% | Mean age 28±12 years | 75% followed 2nd dose | NC | NC | |
| 20 | Lai61 | Case-control | 23 February – 2 August 2021 | Comirnaty and Sinovac CoronaVac | Patients aged 12 and over, electronic health records provided by the Hospital Authority (HA) of Hong Kong; linked with population-based vaccination records | Comirnaty n=20 | 62.5% of 160 carditis cases overall | Mean (SD) age 57.48 (24.23) years overall for vaccinated and unvaccinated participants | 75.0% followed 2nd dose | Carditis aOR=3.57 (95% CI 1.93 to 6.60) | NC | |
| 21 | Li49 | VAERS analysis | 11 December 2020 – 13 August 2021 | All COVID vaccines | VAERS reports | Comirnaty n=1335 cases; Spikevax n=703 |
Spikevax=69.6%, Comirnaty=73.8% | Spikevax recipients aged 18 and older, Comirnaty recipients aged 12 and older | 63.47% followed 2nd dose | NC | Incidence rate=5.98 (95% CI=5.73 to 6.24) cases per million doses administered | |
| 22 | Li29 | Cohort | 10 March – 18 October 2021 | Comirnaty | Hong Kong adolescents, electronic health records | n=43 (myocarditis) | 88% | Mean (SD) 14.86 (1.46) years | 84% followed 2nd dose | NC | NC | |
| 23 | Mevorach31 | Retrospective cohort | 20 December 2020 – 31 May 2021 | Comirnaty | Medical records, Ministry of Health database (Israel) | n=142 (myocarditis) | 91% of the 95 cases for whom age and sex were available | 16 years and older | 91% followed 2nd dose | Rate Ratio=2.35 (95% CI, 1.10 to 5.02) | NC | |
| 24 | Nygaard62 | Prospective nationwide population-based cohort study | 15 May 2021 – 15 September 2021 | mRNA COVID vaccines | Hospitalised adolescents | Comirnaty n=15 | 87% | Range 13–17 years | 47% after 2nd dose | NC | Males: 97 per million Females: 16 per million |
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| 25 | Oh63 | Retrospective observational study | 1 June 2021 – 15 October 2021 | mRNA COVID vaccines | Patients presenting at the Incheon and Daejeon hospitals’ emergency departments | n=4 (myocarditis) | 100% | Range 17–49 years | 50% after 2nd dose | NC | NC | |
| 26 | Oster64 | VAERS analysis | December 2020 – August 2021 | mRNA COVID vaccines | VAERS reports | n=1626 (myocarditis) | 82% | Median=21 years (IQR 16–31) | 82% after 2nd dose | NC | NC | |
| 27 | Patone65 | Population-based cohort study | NR | Comirnaty or AZ | England | Myocarditis n=397; Pericarditis n=356 | Myocarditis=50% following 1st dose, 57.8% following 2nd dose; Pericarditis=62.7% following 1st dose, 69.3% following 2nd dose | Myocarditis 1st dose mean (SD) 55.2 (22.0) years, myocarditis 2nd dose mean (SD) 61 (22.8) years; Pericarditis 1st dose mean (SD) 57.6 (20.1) years, Pericarditis 2nd dose mean (SD) 63.2 (18.7) years |
52.1% received 1st dose only | Myocarditis 1st dose RR=1.31 (95% CI 1.03 to 1.66); Myocarditis 2nd dose RR=1.30 (95% CI 0.98 to 1.72); Pericarditis - No association |
NC | |
| 28 | Sa66 | observational study (VAERS) | 14th Dec 2020 – 30th Sept 2021 | Comirnaty Spikevax or Janssen | USA population, aged over 18 years | Comirnaty n=1072; Spikevax n=791 |
NR | n=1573 18–64 years, n=193 65 years and older | NR | NC | NC | |
| 29 | Simone67 | retrospective population-based cohort study | 14 December 2020 – 20 July 2021 | mRNA COVID vaccines | Kaiser Permanente Southern California (KPSC) members aged 18 years and older |
n=15 (myocarditis) | 100% | Median (IQR) 52 (32–59) years | 86.7% followed 2nd dose | 1st dose: RR=0.38 (95%CI 0.05 to 1.40) 2nd dose: RR=2.7 (95% CI 1.4 to 4.8) |
NC | |
| 30 | Truong68 | Retrospective cohort | Until 4 July 2021 | All COVID vaccines | adolescents and young adults<21 years old, presenting at 26 paediatric medical centres across USA and Canada | Comirnaty n=131, Spikevax n=5 | 90.60% | Median 15.8 (range 12.1–20.3) years | 91.4% followed 2nd dose | NC | NC | |
| 31 | Tsun Lai69 | population-based retrospective cohort study | 1 January 2018 – 30 September 2021 | Comirnaty or CoronaVac | Inpatients 12 years and older (Hong Kong) | N=38 (myocarditis) | NR | NR | 1 or 2 doses | 1st dose: RR=9.15 (95% CI 1.14 to 73.16); 2nd dose: RR=29.61 (95% CI 4.04 to 217.07) |
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| 32 | Witberg70 | Population-based cohort study | 42 days after dose 1 | Comirnaty | Clalit Health Services, electronic health records for patients aged 16 years or older | n=54 (myocarditis) | 94% | Median (IQR)=27 (21–35) years | one dose | NC | Overall: 2.13 (95% CI 1.56 to 2.70) per 100 000 | |
| 33 | Yap71 | Reports to Singapore’s vaccine safety committee | January 2021 – July 2021 | mRNA COVID vaccines | Singapore | n=34 (pericarditis, myocarditis, or concomitant pericarditis and myocarditis) | 82.40% | Myocarditis median 23 (range 12–55) years | 64% followed second dose | NC | NC |
aOR, adjusted OR; NC, not calculated; RR, Risk or Rate Ratio.