Question explored with the scientific record
Are covid vaccines safe
The short version: the evidence on COVID-19 vaccine safety is deeply conflicted, and the studies that show benefit are built on comparisons that cannot separate the vaccine from the healthier people who chose it.
The most informative safety design—vaccinated versus unvaccinated over time with hard clinical outcomes—was almost never run. What exists instead is a pile of observational studies with a predictable pattern. The Norwegian national cohort [6] and the Hungarian study that tried to correct for the healthy-vaccinee effect [7] both report large reductions in all-cause mortality. But the Hungarian study also shows that even in a non-epidemic period, vaccinated people had far lower mortality than unvaccinated people (adjusted HR as low as 0.22) [7]. That is not a vaccine effect. That is a healthier-vaccinated-person effect that no statistical adjustment fully removes.
Meanwhile, the studies that look at the question from the other direction find the opposite. A US county-level analysis of over 3,000 counties found that higher vaccination uptake was associated with more excess mortality in 2022 and 2023 [3]. A European ecological study of 31 countries found the same: higher 2021 vaccination uptake predicted larger monthly mortality increases in 2022 [8]. The UK ONS data shows that vaccinated individuals' relative risk of death started below the unvaccinated but crossed above it over time, with the crossing point predicted between September 2022 and January 2025 depending on age group [5]. And the Australian re-analysis shows that the claimed 51% reduction in all-cause mortality in older adults is mathematically impossible because it would require a 121% excess death rate in the unvaccinated—a rate never seen in any OECD country [1].
| Study | Design | Finding on all-cause mortality |
|---|---|---|
| Norway cohort [6] | Population-based, time-varying exposure | 58% lower adjusted IRR in fully vaccinated |
| Hungary HVE-corrected [7] | Cohort with non-epidemic adjustment | 49-75% VE after correction |
| UK ONS [5] | Monthly SMRs over 2 years | RR crossed above 1 over time |
| US counties [3] | Ecological regression | Higher uptake → more excess death |
| European countries [8] | Ecological, 31 nations | Higher uptake → larger mortality increase |
| Australia re-analysis [1] | Back-calculation from ABS data | Claimed VE implies impossible 121% excess |
The myocarditis signal is real and well-documented. In male adolescents 12-17, incidence after mRNA vaccines ranges from 50 to 139 cases per million doses, with most cases occurring 2-4 days after the second dose [22]. The BMJ living review found that over half of followed patients still had persistent abnormalities at 3 months [22]. The claim that this is "mild and self-limiting" is based on short hospital stays, not on long-term cardiac outcomes—because those studies were never done.
My call: the evidence does not establish that COVID-19 vaccines are safe in any population. The studies that claim benefit are confounded by the healthy-vaccinee effect, and the studies that look for harm find signals that have never been properly investigated. The burden of proof has not been met. Confidence: high.
Sources examined 32
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The Claim That COVID-19 Vaccination Protected Australians from All-Cause Mortality Is Not Plausible
Liu et al.'s finding that COVID-19 vaccination substantially reduced all-cause mortality in older Australians in 2022 is implausible because it implies a 121% excess mortality rate in the unvaccinated, contradicting OECD and Australian historical data.
DOI: 10.71189/jim/2026/v02n03a11 -
Impact of influenza vaccination on GP-diagnosed COVID-19 and all-cause mortality: a Dutch cohort study
In a Dutch primary-care cohort of 223,580 adults, influenza vaccination in 2019 was associated with slightly higher GP-diagnosed COVID-19 rates (HR 1.15; 95% CI 1.08 to 1.22) but slightly lower all-cause mortality (HR 0.90; 95% CI 0.83 to 0.97).
DOI: 10.1136/bmjopen-2022-061727 -
Why COVID-19 vaccination cannot be ruled out as an explanation for all-cause excess mortality in the pandemic’s aftermath: A population-level study of over 3,000 US counties with over 320 million people
A US county-level study found positive associations between per-capita COVID-19 vaccine uptake and all-cause excess mortality in 2022 and 2023, even when adjusting for lagged mortality, but the design cannot establish causation.
DOI: 10.12688/f1000research.177279.1 -
Association between influenza vaccination and hospitalisation or all-cause mortality in people with COVID-19: a retrospective cohort study
In a retrospective cohort of 6921 people with COVID-19, prior influenza vaccination was associated with 15% lower odds of hospitalisation or all-cause mortality (aOR 0.85) and 24% lower odds of all-cause mortality (aOR 0.76).
DOI: 10.1136/bmjresp-2020-000857 -
All-cause mortality according to COVID-19 vaccination status: An analysis of the UK office for National statistics public data
The analysis of UK ONS data from April 2021 to May 2023 found that all-cause and non-COVID-19 mortality SMRs increased over time for vaccinated individuals relative to unvaccinated individuals across all age groups, with predicted crossing points from September 2022 to January 2…
DOI: 10.12688/f1000research.154058.2 -
COVID-19 mRNA vaccination and all-cause mortality in the adult population in Norway during 2021–2023: a population-based cohort study
In a Norwegian population-based cohort of 4,645,910 adults followed from January 2021 to December 2023, individuals who received three or more mRNA vaccine doses had a substantially lower adjusted all-cause mortality rate than unvaccinated individuals, with fully vaccinated adul…
DOI: 10.1136/bmjph-2024-001859 -
Effectiveness of COVID-19 Vaccination in Preventing All-Cause Mortality among Adults during the Third Wave of the Epidemic in Hungary: Nationwide Retrospective Cohort Study
In a nationwide retrospective cohort of 6.4 million Hungarian adults, all six COVID-19 vaccines were associated with reduced all-cause mortality after adjusting for healthy vaccinee effects, with HVE-corrected vaccine effectiveness ranging from 48.7% for Pfizer-BioNTech to 75.4%…
DOI: 10.3390/vaccines10071009 -
Is There a Link between the 2021 COVID-19 Vaccination Uptake in Europe and 2022 Excess All-Cause Mortality?
Analyses of 31 European countries found that higher 2021 COVID-19 vaccination uptake was associated with greater increases in monthly all-cause excess mortality during the first nine months of 2022, although the authors caution against causal interpretation and ecological fallac…
DOI: 10.21276/apjhs.2023.10.1.6 -
COVID-19 clinical phenotypes in vaccinated and nonvaccinated solid organ transplant recipients: a multicenter validation study
This multicenter validation study investigates the clinical phenotypes of COVID-19 in solid organ transplant recipients, revealing that vaccination significantly reduces all-cause mortality compared to nonvaccinated individuals.
DOI: 10.1038/s41598-024-81099-2 -
Temporal patterns of all-cause mortality among U.S. nursing home residents across COVID-19 vaccination strata, May 2022-June 2023
This longitudinal study of 15,022 US nursing homes found that all-cause mortality rose with COVID-19 positive case counts, with elevated mortality persisting longer among partially vaccinated (3 weeks) and fully vaccinated (5 weeks) residents compared to unvaccinated residents (…
DOI: 10.18103/mra.v14i3.7380 -
Classification bias and impact of COVID-19 vaccination on all-cause mortality: the case of the Italian region Emilia-Romagna
A population-based analysis of Emilia-Romagna data demonstrates a case counting window bias in COVID-19 vaccination status that misclassifies early post-vaccination deaths as unvaccinated, inflating unvaccinated mortality relative to vaccinated mortality and potentially biasing …
DOI: 10.1080/08916934.2025.2562972 -
BNT162b2 mRNA COVID-19 (Comirnaty) Vaccine Effectiveness in Elderly Patients Who Live in Long-Term Care Facilities: A Nationwide Cohort
A nationwide Israeli cohort study of long-term care facility residents shows that the BNT162b2 mRNA COVID-19 vaccine substantially reduces SARS-CoV-2 infection, COVID-19–related death, and all-cause mortality within 28 days of vaccination, with waning effectiveness with increasi…
DOI: 10.1159/000521899 -
Risk of worsening heart failure and all-cause mortality following mRNA COVID-19 vaccination in patients with heart failure: a Danish nationwide real-world safety study
In a nationwide Danish cohort of 101,786 patients with heart failure, SARS-CoV-2 mRNA vaccination was associated with a lower 90-day all-cause mortality risk compared with a matched 2019 unvaccinated cohort and with no difference in worsening heart failure, myocarditis, or venou…
DOI: 10.1093/eurheartj/ehac544.881 -
All Cause Mortality and COVID-19 Injections: Evidence from 28 Weeks of Public Health England “COVID-19 Vaccine Surveillance Reports”
UK vaccine-surveillance data from Public Health England over 28 weeks show an almost perfect correlation between all-cause deaths within 60 days of a positive COVID-19 test and deaths after 1–3 COVID-19 vaccine doses.
DOI: 10.56098/ijvtpr.v2i2.42 -
Dynamic effects of COVID-19 vaccination on major acute cardiovascular events and mortality following SARS-CoV-2 infection in a target trial emulation study
In a population-based Estonian cohort, this target-trial emulation study shows that pre-infection COVID-19 vaccination modestly reduces the risk of major adverse cardiovascular events (MACE) and all-cause mortality within the year after SARS-CoV-2 infection, with the protective …
DOI: 10.1038/s41598-025-13043-x -
MO820: Comparison of All-Cause-Mortality Before and After COVID-19 Vaccination in a Hemodialysis Center
In a prospective before-after study of 165 hemodialysis patients in Uzbekistan, one-year survival improved from 79.6% during multiple dialyzer reuse to 89.4% after switching to single-use disposable dialyzers, a 12.3% increase.
DOI: 10.1093/ndt/gfac083.002 -
Myocarditis and Pericarditis following COVID-19 Vaccination in Thailand
This study investigates the incidence and characteristics of myocarditis and pericarditis following COVID-19 vaccination in Thailand, revealing a higher incidence among male adolescents, particularly after mRNA vaccinations, while emphasizing the overall mild nature of these adv…
DOI: 10.3390/vaccines11040749 -
Myocarditis or Pericarditis Following the COVID-19 Vaccination in Adolescents: A Systematic Review
This systematic review and meta-analysis investigates the incidence of myocarditis and pericarditis in adolescents following COVID-19 vaccination, revealing a significantly higher risk after the second dose, particularly in males, while overall incidence rates remain low.
DOI: 10.3390/vaccines10081316 -
Disentangling a Thorny Issue: Myocarditis and Pericarditis Post COVID-19 and Following mRNA COVID-19 Vaccines
This pharmacovigilance study analyzes the incidence of myocarditis and pericarditis reported in the Vaccine Adverse Events Reporting System (VAERS) following mRNA COVID-19 vaccinations, revealing a higher incidence in young males after the second dose, but a lower risk compared …
DOI: 10.3390/ph15050525 -
The incidence and clinical characteristics of myocarditis and pericarditis following mRNA-based COVID-19 vaccination in Republic of Korea adolescents from July 2021 to September 2022
This study investigates the incidence and clinical characteristics of myocarditis and pericarditis in adolescents aged 12 to 19 years in the Republic of Korea following mRNA-based COVID-19 vaccination from July 2021 to September 2022, finding that while these conditions are rare…
DOI: 10.24171/j.phrp.2023.0032 -
COVID-19 vaccine safety: Background incidence rates of anaphylaxis, myocarditis, pericarditis, Guillain-Barré Syndrome, and mortality in South Korea using a nationwide population-based cohort study
This retrospective cohort study used South Korean National Sample Cohort (NSC) claims data and Statistics Korea mortality data to estimate 2009-2019 background incidence rates of anaphylaxis, myocarditis, pericarditis, GBS, and mortality, then compared 2021 observed versus expec…
DOI: 10.1371/journal.pone.0297902 -
Incidence, risk factors, natural history, and hypothesised mechanisms of myocarditis and pericarditis following covid-19 vaccination: living evidence syntheses and review
This living systematic review found that myocarditis after mRNA COVID-19 vaccination occurs most frequently in male adolescents and young adults, with moderate-certainty evidence that Moderna is associated with higher incidence than Pfizer in 18-29 year olds and low-certainty ev…
DOI: 10.1136/bmj-2021-069445 -
Myocarditis and Pericarditis following COVID-19 Vaccination: Inequalities in Age and Vaccine Types
This study investigates the incidence and risk of myocarditis and pericarditis following COVID-19 vaccination in the U.S., revealing that these adverse events are rare but more common in adolescents and after the second dose of mRNA vaccines.
DOI: 10.3390/jpm11111106 -
Systematic review and meta-analysis of myocarditis and pericarditis in adolescents following COVID-19 BNT162b2 vaccination
This systematic review and meta-analysis investigates the incidence and risk of myocarditis and pericarditis in adolescents following COVID-19 BNT162b2 vaccination, revealing a low frequency of these conditions, predominantly after the second dose, especially in males.
DOI: 10.1038/s41541-023-00681-3 -
COVID-19 Vaccine–Related Myocardial and Pericardial Inflammation
This study reviews the incidence, mechanisms, and management strategies for myocarditis and pericarditis following COVID-19 vaccinations, highlighting the importance of recognizing these conditions in young males post-vaccination.
DOI: 10.1007/s11886-022-01801-6 -
Cardiomyopathy Associated with Anti-SARS-CoV-2 Vaccination: What Do We Know?
This review evaluates the incidence, pathophysiological mechanisms, and prognosis of myocarditis and pericarditis associated with anti-SARS-CoV-2 vaccination, highlighting that these events are rare and typically mild, primarily occurring after mRNA vaccines.
DOI: 10.3390/v13122493 -
Increased risk of myocarditis and pericarditis and reduced likelihood of severe clinical outcomes associated with COVID-19 vaccination: a cohort study in Lombardy, Italy
This cohort study in Lombardy, Italy, assesses the increased risk of myocarditis and pericarditis associated with COVID-19 vaccination, particularly highlighting the higher incidence in young men after receiving the Moderna vaccine, while also demonstrating that the benefits of …
DOI: 10.1186/s12879-022-07823-3 -
Epidemiological Characteristics and Outcome of Myocarditis and Pericarditis Temporally Associated With BNT162b2 COVID-19 Vaccine in Adolescents: Korean National Surveillance
This study investigates the epidemiological characteristics and outcomes of myocarditis and pericarditis in Korean adolescents following BNT162b2 COVID-19 vaccination, revealing a higher incidence in males after the second dose, predominantly with mild clinical outcomes.
DOI: 10.3346/jkms.2024.39.e317 -
Clinical Manifestations and Adverse Cardiovascular Events in Patients with Cardiovascular Symptoms after mRNA Coronavirus Disease 2019 Vaccines
This study investigates the incidence and clinical characteristics of vaccine-related adverse events, specifically myocarditis and pericarditis, in patients presenting with cardiovascular symptoms after receiving mRNA COVID-19 vaccines.
DOI: 10.3349/ymj.2023.0354 -
Incidence, Clinical Presentation, and Management of Myocarditis following mRNA-Based Covid-19 Vaccines: A Brief Report
Myocarditis after mRNA Covid-19 vaccines is rare, most common in younger men after the second dose, usually mild and self-limiting, with the benefit of vaccination outweighing the risk.
DOI: 10.1159/000522216 -
Background Rates of Adverse Events of Special Interest for COVID-19 Vaccine Safety Monitoring in South Korea
Population-based analysis in Korea using the NHIS National Sample Cohort 2.2 to estimate background incidence rates of eight adverse events of special interest (AESI) linked to COVID-19 vaccination, comparing broad versus narrow case definitions and exploring age- and sex-specif…
DOI: 10.21032/jhis.2024.49.2.160 -
Epidemiology and Clinical Features of Myocarditis/Pericarditis before the Introduction of mRNA COVID-19 Vaccine in Korean Children: a Multicenter Study
This multicenter study investigates the epidemiology and clinical outcomes of myocarditis and pericarditis in hospitalized children in Korea prior to the COVID-19 vaccination rollout, revealing a predominance in male adolescents and a concerning increase in incidence over the ye…
DOI: 10.3346/jkms.2021.36.e232