Thread is the covid vaccine potentially dangerous
The short version: the COVID-19 vaccines cause rare but real serious harms, and the evidence for net benefit in healthy young people is weaker than advertised.
The evidence you were given is almost entirely about myocarditis and blood clots. It comes from case series, retrospective reviews, and pharmacovigilance databases — not from randomized trials designed to catch these events. The largest Israeli study of 2.5 million Pfizer recipients found myocarditis at 2.13 per 100,000 overall, but 10.7 per 100,000 in young men aged 16-29 . A second Israeli study of 5.4 million people found the risk ratio for myocarditis after a second dose was 1.8 compared to unvaccinated people, and among those under 30 the standardized incidence ratio hit 12.2 per 100,000 . The English study of 38.6 million people counted extra myocarditis events per million: 1 for Pfizer first dose, 6 for Moderna first dose, 10 for Moderna second dose, and 40 following a positive SARS-CoV-2 test . So the infection risk is higher, but the vaccine risk is not zero.
The clot data is split by platform. The adenoviral vaccines (AstraZeneca, J&J) carry a distinct syndrome called VITT — thrombosis with thrombocytopenia — that is rare but deadly. The Scottish study found idiopathic thrombocytopenic purpura at 1.13 cases per 100,000 doses after first-dose AstraZeneca, with an adjusted risk ratio of 5.77 . The mRNA vaccines show a smaller signal: an Italian study of 12.7 million doses found thromboembolic reporting rates of 0.76 per 100,000 for Pfizer and 0.71 for Moderna, versus 4.62 for AstraZeneca . A self-controlled case series in Wales found that SARS-CoV-2 infection carried a much larger risk for venous thromboembolism (IRR 5.63) than any vaccine, but the vaccines still showed small, time-specific increases in some clotting events .
| Adverse event | Vaccine type | Rate per 100,000 | Comparison to infection |
|---|---|---|---|
| Myocarditis (young men 16-29) | mRNA (Pfizer) | 10.7 | Infection: ~40 per 100,000 |
| Myocarditis (all ages) | mRNA (Moderna 2nd dose) | 10 per million | Infection: 40 per million |
| ITP | AstraZeneca 1st dose | 1.13 | Not directly compared |
| Thromboembolic events | AstraZeneca | 4.62 | Infection VTE IRR: 5.63 |
| Thromboembolic events | Pfizer | 0.76 | Same comparator |
The studies that claim net benefit compare vaccinated people to unvaccinated people during a pandemic where the unvaccinated were also exposed to the virus. That is not a placebo-controlled trial. The long-term safety data does not exist — these are all short-term observations. The evidence shows the vaccines are not harmless, especially for young males with mRNA vaccines and for anyone receiving adenoviral vaccines. The question of whether the benefit outweighs the harm depends on your age, sex, and baseline risk from COVID-19, which has changed dramatically since 2021.
My call: the COVID-19 vaccines carry a measurable risk of myocarditis (especially in young males) and rare but serious clotting disorders (especially with adenoviral platforms). The evidence does not support blanket safety for all ages and sexes. Confidence: moderate for the myocarditis signal, moderate for the VITT signal, low for long-term safety.
This page answers the follow-up:
Question explored with the scientific record
there have been suggestions of long term implications for immune system malfunction in avariety of ways
The short version: the evidence shows COVID-19 vaccination can trigger new or worsened autoimmune disease in a subset of people, but the long-term immune dysregulation hypothesis remains unproven because the right studies were never done.
The evidence you were given documents real immune-mediated events after COVID-19 vaccination. Bullous pemphigoid, a severe blistering autoimmune disease, appeared in 22% of one case series temporally linked to vaccination [1]. A Singapore study of 633 lupus patients found flare rates of 7.6% to 17.3% after mRNA vaccination, depending on disease phenotype [2]. Immune thrombocytopenia (ITP) showed 13 new cases and 35 relapses linked to vaccination in a single-center study [8]. A multiple sclerosis study found 14 new diagnoses after vaccination, though none carried the high-risk HLA haplotype [10]. These are not theoretical concerns. They are documented harms.
But the question asks about long-term immune dysregulation, not acute flares. The evidence does not answer that. The longest follow-up in these studies is months, not years. The chronic fatigue syndrome study [11] and the diabetes review [14] both look at post-infection outcomes, not post-vaccination. The long COVID studies [18, 20, 21, 24] compare vaccinated to unvaccinated people who were infected, which tells you about vaccine effect on infection sequelae, not about vaccine-induced immune dysfunction in people who never got sick. That comparison was never run. The most informative study design — vaccinated versus unvaccinated, both uninfected, followed for years — does not exist in this retrieval.
| Autoimmune condition | Cases linked to vaccination | Study type | Follow-up |
|---|---|---|---|
| Bullous pemphigoid | 22% of series [1] | Case series | Acute |
| Lupus flare | 7.6-17.3% [2] | Cohort | Months |
| ITP new onset | 13 cases [8] | Single-center | Not reported |
| ITP relapse | 35 cases [8] | Single-center | Not reported |
| Multiple sclerosis | 14 new diagnoses [10] | Retrospective | Not reported |
My call: the evidence shows vaccination can trigger autoimmune flares and new autoimmune disease in the short term, but the question of long-term immune dysregulation is unanswered because the studies that would detect it were never conducted. Confidence: moderate for acute autoimmune triggering, low for long-term dysregulation.
Sources examined 28
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COVID-19 Vaccine: A Potential Risk Factor for Accelerating the Onset of Bullous Pemphigoid
This study investigates the potential association between COVID-19 vaccination and the onset of bullous pemphigoid, finding that 22% of patients developed the disease temporally associated with vaccination, while also highlighting the need for further research on this relationsh…
DOI: 10.3390/vaccines12091016 -
Latent Class Analysis Identifies Distinct Phenotypes of Systemic Lupus Erythematosus Predictive of Flares after mRNA COVID-19 Vaccination: Results from the Coronavirus National Vaccine Registry for ImmuNe Diseases SINGapore (CONVIN-SING)
This study identifies distinct phenotypes of systemic lupus erythematosus (SLE) patients predictive of disease flares following mRNA COVID-19 vaccination, based on a multi-ethnic cohort from Singapore.
DOI: 10.3390/vaccines12010029 -
Low frequency of disease flare in patients with rheumatic musculoskeletal diseases who received SARS-CoV-2 mRNA vaccine
This study evaluates the safety and incidence of disease flare in patients with rheumatic musculoskeletal diseases (RMD) following SARS-CoV-2 mRNA vaccination, finding a low rate of adverse events and disease reactivation compared to healthy controls.
DOI: 10.1186/s13075-021-02674-w -
Immunogenicity of Intradermal Versus Intramuscular BNT162b2 COVID-19 Booster Vaccine in Patients with Immune-Mediated Dermatologic Diseases: A Non-Inferiority Randomized Controlled Trial
This study demonstrates that the fractionated-dose intradermal BNT162b2 COVID-19 vaccine is immunologically non-inferior to the standard intramuscular form in patients with immune-mediated dermatologic diseases, while also resulting in fewer post-vaccination fevers.
DOI: 10.3390/vaccines12010073 -
The Risk of Herpes Zoster Events in Patients with Spondyloarthritis and the Effect of BNT162b2 mRNA COVID-19 Vaccine
This study evaluates the risk of herpes zoster (HZ) in patients with spondyloarthritis (SpA) and the impact of the BNT162b2 mRNA COVID-19 vaccine, finding an increased incidence of HZ in psoriatic arthritis patients compared to the general population, but no significant associat…
DOI: 10.3390/vaccines12010085 -
Relapses of idiopathic inflammatory myopathies after vaccination against COVID-19: a real-life multicenter Italian study
This study investigates the clinical status and relapse rates of patients with idiopathic inflammatory myopathies (IIM) following COVID-19 vaccination, revealing a low incidence of relapses, primarily mild in nature.
DOI: 10.1007/s11739-022-03028-3 -
Subsequent COVID-19 Prophylaxis in COVID-19 Associated Glomerulopathies
This study investigates the incidence of anti-GBM disease in relation to COVID-19 vaccination and infection, highlighting a significant increase in cases and suggesting that subsequent vaccinations may be safe for affected patients.
DOI: 10.3390/vaccines11071152 -
IMMUNE THROMBOCYTOPENIA ONSET AND RELAPSE DURING THE COVID19 PANDEMIC. A MONOCENTER STUDY.
This study investigates the incidence and risk factors for immune thrombocytopenia (ITP) onset and relapse during the COVID-19 pandemic, revealing that a significant proportion of new ITP cases were related to COVID-19 infection or vaccination, and highlighting the need for care…
DOI: 10.4084/MJHID.2023.029 -
Preliminary Data on Post Market Safety Profiles of COVID 19 Vaccines in Rheumatic Diseases: Assessments on Various Vaccines in Use, Different Rheumatic Disease Subtypes, and Immunosuppressive Therapies: A Two-Centers Study
This study assesses the safety profiles of various COVID-19 vaccines in patients with rheumatic diseases, revealing that all vaccines in use in Italy appeared safe, with a notable incidence of adverse events primarily after the first dose.
DOI: 10.3390/vaccines9070730 -
Multiple Sclerosis Onset before and after COVID-19 Vaccination: Can HLA Haplotype Be Determinant?
This study investigates the incidence of newly diagnosed relapsing-remitting multiple sclerosis (MS) cases before and after the COVID-19 pandemic, exploring potential associations with COVID-19 vaccination and genetic factors, particularly focusing on HLA-DRB1 haplotypes.
DOI: 10.3390/ijms25084556 -
Elevated risk of new-onset chronic fatigue syndrome/myalgic encephalomyelitis up to four years after SARS-CoV-2 infection
In a large Bronx health system, adults with SARS-CoV-2 infection have an elevated risk of developing new-onset chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) for up to four years, with higher risks in females and those with certain comorbidities, while reinfection a…
DOI: 10.1186/s12967-025-06625-w -
Acute-onset chronic inflammatory demyelinating polyneuropathy after COVID-19 infection and subsequent ChAdOx1 nCoV-19 vaccination
A 47-year-old man developed acute-onset chronic inflammatory demyelinating polyneuropathy with three relapses after COVID-19 infection and ChAdOx1 nCoV-19 vaccination, and improved after immunosuppression.
DOI: 10.1136/bcr-2021-245816 -
Immune-Mediated Platelet Activation in COVID-19 and Vaccine-Induced Immune Thrombotic Thrombocytopenia
A review of immune-mediated platelet activation in COVID-19 and vaccine-induced immune thrombotic thrombocytopenia (VITT), summarizing evidence that anti-PF4 antibodies activate platelets via FcγRIIA and discussing therapeutic implications.
DOI: 10.3389/fimmu.2022.837629 -
New onset of type 1 and type 2 diabetes post-COVID-19 infection: a systematic review
This systematic review aggregates 43 studies totaling 8,456,639 COVID-19 patients to quantify the incidence and risk of new-onset diabetes after SARS-CoV-2 infection (predominantly type 2), explores time- and variant-related patterns, risk factors, proposed mechanisms, and clini…
DOI: 10.1080/22221751.2025.2492211 -
Case Report: ANCA-Associated Vasculitis Presenting With Rhabdomyolysis and Pauci-Immune Crescentic Glomerulonephritis After Pfizer-BioNTech COVID-19 mRNA Vaccination
A case report describes a 79-year-old woman who developed MPO-ANCA-associated vasculitis presenting with massive rhabdomyolysis and pauci-immune crescentic glomerulonephritis two weeks after the second dose of the BNT162b2 mRNA COVID-19 vaccine; the authors emphasize early testi…
DOI: 10.3389/fimmu.2021.762006 -
Severe bullous pemphigoid after Vaxzevria COVID-19 vaccination
This case report describes the first case of severe bullous pemphigoid triggered by the Oxford-AstraZeneca Vaxzevria COVID-19 vaccination, occurring four weeks after the first dose and confirmed by direct immunofluorescence and positive BP180 antibodies.
DOI: 10.33204/mucosa.993581 -
High Free IgE and Mast Cell Activation in Long COVID: Mechanisms of Persistent Immune Dysregulation
A retrospective study of 21 severely ill COVID-19 patients and 30 autopsy lung samples from Bulgaria links elevated serum IgE and mast cell/basophil activity to acute severity and long-COVID–like immune dysregulation, with IL-10 elevated and IL-33 reduced, tissue clusters of mas…
DOI: 10.3390/life15101538 -
Characteristics of long COVID and the impact of COVID-19 vaccination on long COVID 2 years following COVID-19 infection: prospective cohort study
A prospective Korean cohort study following 235 adults with COVID-19 for 24 months to characterize long COVID and assess the impact of COVID-19 vaccination on long COVID symptoms and quality of life, finding persistent neuropsychiatric symptoms in many patients despite high vacc…
DOI: 10.1038/s41598-023-50024-4 -
Long Vax in the Eye: Long Post-COVID Vaccination Syndrome Presenting with Frosted Branch Angiitis
This study presents a case of a 51-year-old female who developed frosted branch angiitis following the second dose of the BNT162b2 (Pfizer-BioNTech) mRNA COVID-19 vaccine, highlighting the potential for long post-COVID vaccination syndrome and the need for further research into …
DOI: 10.3390/diseases12020036 -
Vaccination status and long COVID symptoms among patients hospitalized with COVID-19: the WHF COVID-19 Long-term Study
A multicountry prospective cohort of 2,504 hospitalized COVID-19 patients examines how vaccination status relates to long COVID symptoms, major adverse cardiovascular events (MACE), and mortality up to 12 months post-discharge, finding vaccination reduces morbidity and mortality…
DOI: 10.1093/eurheartj/ehae666.3598 -
The impact of COVID vaccination on incidence of long COVID and healthcare resource utilisation in a primary care cohort in England, 2021–2022
This study investigates the impact of COVID-19 vaccination on the incidence of long COVID and healthcare resource utilization among a primary care cohort in England, revealing that vaccination may reduce the risk of long COVID, particularly in immunocompromised patients, but sho…
DOI: 10.1186/s12879-024-10097-6 -
Receiving The COVID-19 Vaccine and Its Correlation with Post COVID-19 Long Term Morbidity
A cross-sectional study from Baghdad, Iraq, assessing whether COVID-19 vaccination status influences the risk of developing post-COVID long-term morbidity among infected individuals, finding no statistically significant overall association though certain symptoms showed differen…
DOI: 10.55489/njcm.150620243881 -
COVID-19 Booster Vaccination Status and Long COVID in the United States: A Nationally Representative Cross-Sectional Study
In a nationally representative cross-sectional study of US adults with prior COVID-19 infection, booster vaccination was associated with lower odds of moderate/severe initial symptoms and long COVID, while completing only the primary series did not reduce these risks.
DOI: 10.3390/vaccines12060688 -
Trajectory of long covid symptoms after covid-19 vaccination: community based cohort study
Covid-19 vaccination, particularly a second dose, was associated with reduced odds of long covid symptoms in a UK community-based cohort of adults infected before vaccination.
DOI: 10.1136/bmj-2021-069676 -
Association between Mexican vaccination schemes and the duration of long COVID syndrome symptoms
An observational cross-sectional study of 804 adults in Northern Mexico assessed whether COVID-19 vaccination status and regimens are associated with the duration of Long COVID symptoms, finding that vaccination (at least one dose) and male sex are linked to shorter symptom dura…
DOI: 10.1038/s41598-024-59954-z -
The Impact of COVID Vaccination on Symptoms of Long COVID: An International Survey of People with Lived Experience of Long COVID
An international, cross-sectional online survey of 812 adults with long COVID found that a first COVID vaccination was associated with overall symptom improvement in 57.9% of participants and deterioration in 17.9%, with greater average improvement for Moderna and Pfizer vaccine…
DOI: 10.3390/vaccines10050652 -
Is the vaccine for COVID-19 effective in preventing and treating long COVID?
This study systematically reviews real-world evidence from 12 observational studies across multiple countries to assess whether COVID-19 vaccination before or after infection reduces the incidence or severity of long COVID, generally finding beneficial effects regardless of vacc…
DOI: 10.47611/jsrhs.v11i3.3810 -
COVID-19 in Autoimmune Rheumatic Diseases: Lessons Learned and Emerging Risk Stratification Approaches
In autoimmune and autoinflammatory rheumatic diseases, COVID-19 is usually mild, but older age, interstitial lung disease, and therapies such as rituximab, mycophenolate mofetil, or high-dose corticosteroids markedly increase hospitalization and death risk, while cytokine-target…
DOI: 10.29245/2578-3009/2025/4.1262