A major 2025 UK study examining COVID-19 vaccination outcomes in over 1.7 million children and adolescents has reignited public discussion about vaccine safety. While some outlets have highlighted that cases of myocarditis and pericarditis appeared only in vaccinated groups, the absolute numbers remain extremely low. This in-depth analysis presents the actual findings from the OpenSAFELY study, places them in context with other recent UK research, and explores what the data means for families. We examine the science, the headlines, and the broader picture—without bias—so readers can draw their own conclusions.
Introduction: A Study That Sparked Headlines
In September 2025, British researchers published findings from one of the largest real-world analyses of COVID-19 vaccines in children. Using the OpenSAFELY platform—which draws on anonymised health records covering a vast portion of England’s population—the team set out to assess both the effectiveness and safety of Pfizer’s mRNA vaccine in two age groups: adolescents aged 12–15 and younger children aged 5–11.
The study compared vaccinated children with carefully matched unvaccinated controls. While it reported modest reductions in certain COVID-19-related hospital visits among adolescents, the safety data on heart inflammation quickly became the focus of intense online discussion. Some commentators noted that myocarditis and pericarditis events were recorded exclusively in the vaccinated groups during the study period. Others, however, pointed out the extremely low incidence rates and contrasted them with risks associated with actual COVID-19 infection.
“Myocarditis and pericarditis were documented only in the vaccinated groups, with rates of 27 and 10 cases per million after the first and second doses respectively.”— OpenSAFELY Study, Epidemiology, 2025
This neutral, data-driven article examines the original research, the public reaction, and the latest context from complementary UK studies released in late 2025. We link directly to primary sources so you can verify every detail.
The Core Findings of the OpenSAFELY Study
The researchers analysed data from 820,926 adolescents and 441,858 younger children who had not previously received the vaccine, matching them to unvaccinated controls by age, sex, and other key factors. Outcomes tracked included positive SARS-CoV-2 tests, emergency visits, hospitalisations, critical care admissions, and deaths related to COVID-19, alongside safety signals such as unplanned hospitalisations, pericarditis, and myocarditis.
Effectiveness Results
In adolescents, the first dose was associated with a 26% lower rate of positive tests, 40% fewer COVID-19 A&E attendances, and 42% fewer hospitalisations over 20 weeks. A second dose provided further modest reductions. In the younger children’s group, COVID-19 outcomes were too rare to produce precise estimates. Across the entire dataset, there were zero COVID-19-related deaths and fewer than seven critical care admissions in any analysis.
Safety Outcomes – The Myocarditis Question
The study explicitly reported that all documented cases of myocarditis and pericarditis occurred in vaccinated children. Incidence rates were 27 cases per million doses following the first injection and 10 cases per million following the second. No cases were observed in the unvaccinated control groups during the same observation window. Importantly, the absolute numbers remain very small—equivalent to roughly 0.0027% after the first dose.
These figures align with earlier pharmacovigilance data from the UK’s Yellow Card scheme and international surveillance systems, which have consistently described vaccine-associated myocarditis as rare, predominantly mild, and more common in adolescent males after the second dose.
How the Findings Were Reported Online
Within hours of the study’s wider circulation, headlines appeared on independent news platforms emphasising the “only in vaccinated groups” detail. Infowars, for example, ran the accurate but attention-grabbing title “Myocarditis/Pericarditis Documented ONLY Among Vaxxed Kids in Large UK Study.”
Shortly afterwards, The People’s Voice published an article dated March 23, 2026, with the more dramatic claim: “UK Gov’t Admit 98% of Vaxxed Kids Now Have Myocarditis.” That article, which can be read in full here, directly references the same OpenSAFELY paper but interprets the “only in vaccinated” observation as evidence of widespread harm.
Note: The figure “98%” does not appear in the original study. It appears to be a misinterpretation or conflation with the fact that some related UK paediatric research has covered data from approximately 98% of England’s child population. The actual incidence reported remains 10–27 cases per million doses.
Placing the Numbers in Broader Context: Infection vs Vaccination Risk
A separate large-scale UK study published in The Lancet Child & Adolescent Health in November 2025 analysed anonymised records from nearly 14 million children and young people. It found that the risk of myocarditis or pericarditis was higher—and lasted longer—following a COVID-19 infection than following vaccination.
Key comparison (over six months):
- COVID-19 infection → 2.24 extra cases of myocarditis/pericarditis per 100,000 children
- Vaccination → 0.85 extra cases per 100,000 children
The infection-related risk persisted for up to a year in some cases, while the vaccine-associated risk returned to baseline after approximately four weeks. These findings are consistent with multiple international studies and have been summarised by University College London, Cambridge University, and Great Ormond Street Hospital.
Internal Links for Further Reading
For readers interested in related public-health topics, explore Planet Today’s health section for ongoing coverage of environmental factors affecting children’s wellbeing, including emerging research on chemical exposures and neurological health. Additional context on long-term immunity can be found in our recent finance-health crossover piece on post-pandemic economic impacts of childhood wellness trends.
Expert and Official Perspectives
UK health authorities, including the Medicines and Healthcare products Regulatory Agency (MHRA) and NHS, continue to state that the overall benefits of vaccination in protecting against severe COVID-19 outcomes outweigh the rare risk of myocarditis for eligible age groups. Most reported cases resolve with rest and standard care.
Independent researchers at the Science Media Centre and Public Health Collaborative have cautioned against over-interpreting observational studies that lack direct head-to-head comparisons of infection versus vaccination risks within the same dataset. They emphasise that the OpenSAFELY paper was not designed to quantify post-infection myocarditis and that earlier limitations (such as exclusion of certain high-risk children) should be considered.
Public Reaction and Ongoing Debate
The study’s publication coincided with continued global discussion about childhood vaccination policies. Parents, clinicians, and policymakers remain divided: some view the “only in vaccinated” finding as reason for heightened caution, while others stress the extremely low absolute risk and the protective effect against infection-related complications. Social media platforms amplified both the Infowars coverage and fact-checking responses, highlighting the challenge of communicating nuanced epidemiological data to the public.
Regardless of viewpoint, the data underscore the importance of informed consent, transparent risk communication, and continued monitoring of rare adverse events.
Conclusion: Data, Not Drama
The 2025 OpenSAFELY study provides valuable real-world evidence on COVID-19 vaccination in UK children. It documents myocarditis and pericarditis exclusively in the vaccinated cohort at rates of 10–27 cases per million doses—figures that are rare but not zero. Complementary research shows that the heart-inflammation risk from actual COVID-19 infection appears higher and more prolonged. These findings invite careful reading rather than headline-driven conclusions.
Families should discuss individual circumstances with their healthcare providers. Science advances through scrutiny, replication, and open dialogue. We encourage readers to review the primary papers themselves and weigh the evidence accordingly.
Original Source of the Viral Claim: The People’s Voice, “UK Gov’t Admit 98% of Vaxxed Kids Now Have Myocarditis,” published March 23, 2026. Full article: https://thepeoplesvoice.tv/uk-govt-admit-98-of-vaxxed-kids-now-have-myocarditis/