Real-time pharmacovigilance and cardiac risk communication during the COVID-19 vaccination campaign in Israel

Q: What are the key findings of this study?

Among 531 hospitalization records reported following Pfizer COVID-19 vaccination, 47.1% involved myocarditis or pericarditis, rising to 71.6% among patients under 30 years of age.

Q: What is the clinical evidence from this study?

Study design: Observational. Population: Adverse events following COVID-19 vaccination (n=598). Intervention: Pfizer-BioNTech COVID-19 vaccine. Primary outcome: Proportion of hospitalization records involving myocarditis or pericarditis (95% CI 42.9-51.3).

Q: What does this research mean for the field?

Among hospitalization records reported to Pfizer following COVID-19 vaccination in Israel, 47.1% involved myocarditis or pericarditis, rising to 71.6% among patients younger than 30 years of age. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.CHALLENGES_CONSENSUS.

Yaakov Ophir; Yaffa Shir-Raz

doi:10.17179/excli2026-9596_supplementary_information

June 8, 2026Open Access

Real-time pharmacovigilance and cardiac risk communication during the COVID-19 vaccination campaign in Israel

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Key result

Myocarditis or pericarditis accounts for ~47% of hospitalizations reported after Pfizer COVID-19 vaccination.

95% CI 42.9-51.3
n=598

Why the study?

The early identification and communication of myocarditis and pericarditis cases following Pfizer COVID-19 vaccination in young individuals required detailed pharmacovigilance analysis and evaluation of risk communication strategies.

Key Points

To analyze an internal pharmacovigilance dataset from the Israeli Ministry of Health on early safety signals following Pfizer COVID-19 vaccination and examine how these risks were communicated.
Analyzed an internal pharmacovigilance dataset containing 531 analytical hospitalization records and 67 unique deaths reported to Pfizer between March 2021 and May 2022.
Examined clinical categories, age distributions, prior medical history, and post-vaccination intervals across reported adverse event cases.
Mapped the chronological communication timeline of the myocarditis safety signal by health authorities to physicians and the public.
Myocarditis or pericarditis occurred in 250 of 531 hospitalization records (47.1%; 95% CI, 42.9%–51.3%), rising to 151 of 211 records among patients under 30 years of age (71.6%; 95% CI, 65.1%–77.2%).
Patients under 30 had significantly higher odds of myocarditis or pericarditis compared to older patients (71.6% vs. 31.0%; OR, 5.59; 95% CI, 3.82–8.19; p < 0.001), with a strong male predominance (82.9% vs. 31.9%; OR, 10.36; 95% CI, 4.96–21.63; p < 0.001).
Among 67 unique deaths, 9 were individuals under 50 years (13.4%), with myocarditis documented in 2 of these 9 deaths (22.2%; 95% CI, 6.3%–54.7%), while official communication to clinicians was delayed by three to four months.

Study Design

Type

Observational (n=598)

Structured PICO

P

Population

598 individuals (531 hospitalizations and 67 deaths) with suspected adverse events following COVID-19 vaccination reported to Pfizer by the Israeli Ministry of Health between March 2021 and May 2022.

E

Exposure

BNT162b2 COVID-19 vaccine

O

Outcome

Incidence of myocarditis or pericarditis among reported post-vaccination hospitalizations and deathssafety

Limitations

Observational dataset lacking appropriate reporting comparators or background incidence rates.
Does not permit formal disproportionality analysis or population-level causal risk estimation.
Lack of methodological documentation on how all cases were identified, selected, or validated.
No formal audit trail of workbook changes or dataset completeness.
No methodological documentation or data dictionary to independently establish how cases were identified, selected, or entered
Uncertain whether workbooks represent a complete export or a subset curated for reporting
Lack of information regarding what clinical-validation or quality-control procedures were performed
Cannot definitively establish that the reported events were causally related to vaccination

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Implication

Analysis of an internal Israeli pharmacovigilance dataset reveals a strong post-COVID-19 vaccination safety signal for myocarditis and pericarditis, predominantly affecting young males without prior medical history.

Abstract

During the early phase of the COVID-19 vaccination campaign, the Israeli Ministry of Health (IMOH) informed international health authorities that it had identified “a large number of myocarditis and pericarditis cases in young individuals soon after Pfizer COVID-19 vaccine.” This study discloses and analyzes an internal pharmacovigilance dataset obtained from within the IMOH to examine the case-level record associated with this early safety signal and trace how the signal was subsequently communicated to physicians and the public. The anonymized dataset, provided as Supplementary Data File 1, includes 531 hospitalization records and 67 unique deaths reported to Pfizer between March 2021 and May 2022. Reported events spanned cardiac, neurological, inflammatory, and other serious clinical categories and involved a substantial proportion of younger individuals, with 211 of 530 hospitalization records with valid age data (39.8 %) involving patients under 30 years of age. Myocarditis was recorded in two of the nine unique deaths among individuals under 50 years of age (22.2 %), while myocarditis or pericarditis was identified in 250 of 531 hospitalization records (47.1 %), rising to 151 of 211 records involving patients under 30 (71.6 %). Among younger hospitalized patients, 134 of 211 (63.5 %) had no meaningful medical history identified under the study definition; within this subgroup, 99 of 134 (73.9 %) had myocarditis or pericarditis, of whom 90 (90.9 %) were male. The safety signal was communicated to clinicians and the public only after approximately three to four months, primarily in ways that emphasized its rarity, generally mild clinical course, and lower concern relative to COVID-19 outcomes. The accuracy and completeness of this characterization, together with the implications of the case-level patterns and communication timeline documented in this study, are discussed in the broader contexts of pharmacovigilance, risk communication, and informed consent during large-scale public health interventions.

Discussion

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Cite This Study

Ophir et al. (2026) conducted an observational in Adverse events following COVID-19 vaccination (n=598). Pfizer-BioNTech COVID-19 vaccine was evaluated on Proportion of hospitalization records involving myocarditis or pericarditis (95% CI 42.9-51.3). Among 531 hospitalization records reported following Pfizer COVID-19 vaccination, 47.1% involved myocarditis or pericarditis, rising to 71.6% among patients under 30 years of age.

synapsesocial.com/papers/6ad0fce415427f6a84040395 https://doi.org/10.17179/excli2026-9596_supplementary_information

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Real-time pharmacovigilance and cardiac risk communication during the COVID-19 vaccination campaign in Israel

Key Points

Study Design

Structured PICO

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

Real-time pharmacovigilance and cardiac risk communication during the COVID-19 vaccination campaign in Israel

Key Points

Study Design

Structured PICO

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

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