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.
there have been suggestions of long term implications for immune system malfunction in avariety of ways — suggestions of long-term immune system malfunction
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 . A Singapore study of 633 lupus patients found flare rates of 7.6% to 17.3% after mRNA vaccination, depending on disease phenotype . Immune thrombocytopenia (ITP) showed 13 new cases and 35 relapses linked to vaccination in a single-center study . A multiple sclerosis study found 14 new diagnoses after vaccination, though none carried the high-risk HLA haplotype . 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 and the diabetes review both look at post-infection outcomes, not post-vaccination. The long COVID studies 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 | Case series | Acute |
| Lupus flare | 7.6-17.3% | Cohort | Months |
| ITP new onset | 13 cases | Single-center | Not reported |
| ITP relapse | 35 cases | Single-center | Not reported |
| Multiple sclerosis | 14 new diagnoses | 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.
This page answers the follow-up:
Question explored with the scientific record
and also cancer
The short version: chronic immune dysfunction is a well-established driver of cancer, but no study in this retrieval tests whether vaccination causes it.
The evidence you were given documents the link between immune failure and cancer across multiple primary immunodeficiencies. Ataxia-telangiectasia patients carry a 25% lifetime malignancy risk, mostly leukemia and lymphoma, with a hazard ratio for death of 6.9 after malignancy [20]. Common variable immunodeficiency patients face a 47-fold increased risk of stomach cancer [19]. Wiskott-Aldrich syndrome, a severe T-cell disorder, produces EBV-driven Hodgkin lymphoma [21]. The mechanism is consistent: impaired immune surveillance lets transformed cells escape detection and destruction. Chronic inflammation, as seen in C. difficile colitis and bile duct reflux, also drives carcinogenesis through NF-κB and STAT3 signaling [11, 13]. None of this is controversial.
What is missing is any study that measures whether vaccination produces a sustained immune defect large enough to raise cancer risk. The retrieved evidence contains zero long-term follow-up comparing cancer incidence in vaccinated versus unvaccinated populations. The closest match is the HPV vaccine literature, which tracks cervical pre-cancer as an efficacy endpoint, not as a safety question about immune dysfunction [6, 8]. The question you asked — whether chronic immune dysfunction from vaccination increases long-term cancer incidence — cannot be answered from this evidence because the relevant study was never done.
| Primary immunodeficiency | Cancer type | Risk magnitude |
|---|---|---|
| Ataxia-telangiectasia [20] | Leukemia/lymphoma | 25% by age 30; HR 6.9 |
| Common variable immunodeficiency [19] | Stomach cancer | 47-fold RR |
| Wiskott-Aldrich syndrome [21] | Hodgkin lymphoma | Case report, EBV-driven |
My call: the hypothesis is biologically plausible and the mechanism is proven in other contexts, but the evidence retrieved does not test it for vaccination. Confidence: high for the immune-surveillance mechanism in general, not clear for vaccine-induced cancer risk.
Sources examined 25
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Assessment of Augmented Immune Surveillance and Tumor Cell Death by Cytoplasmic Stabilization of p53 as a Chemopreventive Strategy of 3 Promising Medicinal Herbs in Murine 2-Stage Skin Carcinogenesis
This study investigates the chemopreventive effects of methanolic extracts from three medicinal herbs—Trigonella foenumgraecum, Eclipta alba, and Calendula officinalis—on skin carcinogenesis in mice, demonstrating their ability to inhibit tumor growth and enhance immune surveill…
DOI: 10.1177/1534735413513831 -
Hematologic immune-related adverse effects of immune checkpoint inhibitors: a review
A comprehensive narrative review detailing hematologic immune-related adverse events (irAEs) linked to immune checkpoint inhibitors (ICIs), covering epidemiology, clinical presentations across multiple hematologic syndromes, and management strategies with implications for patien…
DOI: 10.1007/s00520-025-09952-2 -
The non-protein coding breast cancer susceptibility locus Mcs5a acts in a non-mammary cell-autonomous fashion through the immune system and modulates T-cell homeostasis and functions
A non-protein coding breast cancer susceptibility locus Mcs5a modulates mammary tumor multiplicity by acting through the immune system to alter T-cell homeostasis, notably γδ T cells and Th1 responses, indicating a non-mammary cell-autonomous mechanism during early cancer progre…
DOI: 10.1186/bcr2933 -
Sensitivity to Carcinogenesis in Nude Mice: Skin Tumors Caused by Transplacental Exposure to Ethylnitrosourea
This study demonstrates that female athymic nude mice exhibit a significantly higher incidence of skin tumors following transplacental and intraperitoneal exposure to ethylnitrosourea compared to their phenotypically normal littermates, suggesting a unique susceptibility to carc…
DOI: 10.1126/science.7134965 -
CANCER, WARTS, AND SUNSHINE IN RENAL TRANSPLANT PATIENTS
Renal transplant recipients in Glasgow exhibit a higher burden of actinic keratoses, cutaneous malignancies, warts, herpes zoster, and fungal infections compared with matched controls, with the highest risks concentrated among those with a history of high sun exposure, suggestin…
DOI: 10.1016/s0140-6736(84)92221-9 -
Monitoring the impact of human papillomavirus vaccines on high-grade pre-invasive cervical lesions: Designing a framework of linked immunization information system and cancer registry data in Michigan
This study assesses the feasibility of linking Michigan's Immunization Information System (IIS) with the state cancer registry to monitor the potential population-level impact of HPV vaccination on high-grade cervical pre-invasive lesions by identifying continuously resident, HP…
DOI: 10.1016/j.vaccine.2014.12.063 -
Improved Intraoperative Eighth Nerve Monitoring
This clinical study links pretreatment natural killer (NK) cell activity to the risk of distant metastases in head and neck cancer patients treated with postoperative radiotherapy, finding that NK activity above 60 LU is associated with only about 5% distant metastases and that …
DOI: 10.1001/archotol.1987.01860090017007 -
Prophylactic human papillomavirus vaccination update
Prophylactic HPV vaccination was implemented in the UK in 2008 for girls aged 12-13 with a catch-up programme up to age 18 using the bivalent vaccine Cervarix, and surveillance is essential to evaluate long-term effectiveness and answer remaining questions.
DOI: 10.1576/toag.11.2.133.27488 -
Bile Duct Cancer Developing 21 Years after Choledochoduodenostomy
A case report of a 67-year-old Japanese woman who developed bile duct cancer 21 years after choledochoduodenostomy, treated with curative pylorus-preserving pancreatoduodenectomy and liver resection; pathology showed tumor origin in the bile duct mucosa with pyloric/intestinal m…
DOI: 10.1159/000071761 -
TRIM31 triggers colorectal carcinogenesis and progression by maintaining YBX1 protein stability through ubiquitination modification
This study identifies TRIM31 as an oncogenic driver in colorectal cancer that promotes tumor growth and metastasis by stabilizing the RNA-binding protein YBX1 via K63-linked ubiquitination, which in turn increases stability of oncogenic mRNAs (EREG, GAS6, MAFG); it also reveals …
DOI: 10.1038/s41419-025-07922-4 -
How chronic inflammation fuels carcinogenesis as an environmental epimutagen
A narrative review explicating how chronic inflammation acts as an environmental epimutagen that drives carcinogenesis through epigenetic alterations, particularly DNA methylation, with emphasis on stomach, colon, and uterine cervical cancers, and discussing inflammation-driven …
DOI: 10.1007/s12672-025-02971-9 -
Does Trichomoniasis Play Any Role in The Pathogenesis of Cervical Carcinoma?
Chronic Trichomonas vaginalis infection may promote HPV-driven cervical carcinogenesis through mucosal inflammation, suggesting TV management could help reduce cervical cancer risk.
DOI: 10.4314/sokjmls.v7i1.7 -
Clostridium difficile as a potent trigger of colorectal carcinogenesis
A perspective review summarizing how Clostridioides difficile toxins (TcdA and TcdB) may drive colorectal carcinogenesis via epithelial barrier disruption, DNA damage, and chronic NF-κB/STAT3–driven inflammation, with emphasis on dysbiosis and potential therapeutic approaches su…
DOI: 10.1007/s12672-025-02742-6 -
Subcutaneous fluid port-associated soft tissue sarcoma in a cat
Long-term subcutaneous fluid port in a cat developed a fibrosarcoma at the port site, suggesting port-related chronic inflammation may contribute to malignant transformation.
DOI: 10.1177/1098612x13478267 -
A food-based approach that targets interleukin-6, a key regulator of chronic intestinal inflammation and colon carcinogenesis
In a human-relevant porcine model of high-calorie diet–induced colonic inflammation, IL-6 signaling was upregulated and linked to increased Ki-67–based proliferation, and dietary intervention with anthocyanin-rich purple-fleshed potatoes (especially baked) suppressed IL-6 expres…
DOI: 10.1016/j.jnutbio.2017.01.012 -
Immunodeficiency risk score for prediction of mortality by parainfluenza virus infection in patients with hematologic malignancy
This retrospective cohort study develops an immunodeficiency risk score to predict 90-day mortality from parainfluenza virus infection in adults with hematologic malignancies with or without hematopoietic stem cell transplantation, demonstrating clear risk stratification but no …
DOI: 10.1007/s00277-020-03996-6 -
Autosomal recessive nonsyndromal microcephaly with normal intelligence
This study describes a new autosomal recessive nonsyndromal variant of microcephaly characterized by normal intelligence, immunodeficiency, and an increased risk for lymphoreticular malignancies, observed in a large Arab kindred with frequent consanguineous marriages.
DOI: 10.1002/ajmg.1320260214 -
Ataxia-telangiectasia: epidemiology, pathogenesis, clinical phenotype, diagnosis, prognosis and management
A comprehensive review summarizing the epidemiology, pathogenesis, clinical phenotype, diagnosis, prognosis, and management of ataxia-telangiectasia (ATM-related primary immunodeficiency), highlighting ATM mutations, immune dysregulation, neurodegeneration, cancer risk, and impl…
DOI: 10.1080/1744666X.2020.1810570 -
Common Variable Immunodeficiency and Gastric Malignancies
This 2018 review synthesizes how common variable immunodeficiency (CVID) predisposes to gastric malignancies and gastric lymphoma, outlining immunological defects, the role of Helicobacter pylori, cancer risk data from CVID cohorts, and implications for screening and management.
DOI: 10.3390/ijms19020451 -
The incidence and type of cancer in patients with ataxia‐telangiectasia via a retrospective single‐centre study
A retrospective single-centre study of 69 patients with ataxia-telangiectasia (A-T) shows a high cancer risk, particularly haematological malignancies, with markedly reduced survival after malignancy and notable male excess in cancer incidence and mortality, underscoring the nee…
DOI: 10.1111/bjh.17736 -
Epstein‐Barr virus‐associated Hodgkin's disease in a patient with Wiskott‐Aldrich syndrome
This study reports a rare case of a boy with Wiskott-Aldrich syndrome who developed Epstein-Barr virus-associated Hodgkin's disease, highlighting the potential link between immunodeficiency and malignancy in such patients.
DOI: 10.1111/j.1651-2227.2001.tb01589.x -
Ataxia-telangiectasia: Immunodeficiency and survival
A retrospective cohort study of 61 ataxia-telangiectasia patients shows classical AT has poorer survival than variant AT, with malignancy and immunoglobulin deficiencies (notably IgG2 deficiency and AT-HIGM) further diminishing survival, highlighting high-risk groups for future …
DOI: 10.1016/j.clim.2017.01.009 -
Respiratory syncytial virus in hematopoietic cell transplant recipients and patients with hematologic malignancies
This 2019 Haematologica review synthesizes what is known about respiratory syncytial virus (RSV) infections in adults with hematologic malignancies and hematopoietic cell transplant recipients, covering incidence, risk factors for progression to lower respiratory tract infection…
DOI: 10.3324/haematol.2018.215152 -
CAR-T Cell therapy in T-cell malignancies: limitations and solutions
A comprehensive review of CAR-T cell therapy for T-cell malignancies, outlining bottlenecks such as autologous T-cell collection, CAR-T fratricide, and immunodeficiency, and evaluating strategies (donor-derived CAR-T, universal CAR-T, PEBL, and gene-editing approaches) with safe…
DOI: 10.15212/hod-2022-0002 -
OBIČNA VARIJABILNA IMUNODEFICIJENCIJA (CVID)
Common Variable Immunodeficiency (CVID) is a genotypically and phenotypically heterogeneous primary immunodeficiency marked by hypogammaglobulinemia and recurrent infections, with frequent autoimmune, granulomatous, and malignant complications, for which lifelong immunoglobulin …
DOI: 10.7251/sceped1801055e