Studies and Research
The body of research on the effects of intramuscular injections is vast and detailed. However, the highly technical language in these studies can be difficult for the general public to understand.
In public health research, authors often soften their wording due to pressure from journals to downplay negative findings on side effects and adverse reactions. As a result, important insights are frequently obscured or carefully phrased in the papers themselves—though they remain visible in the data sets and discussion sections upon close review.
To address this, HFDF has created this searchable compendium of studies, each paired with clear, plain-language summaries and notes prepared by our team. Our goal is to cut through technical complexity, bias, and ambiguity so individuals can access the key facts and make informed health decisions.
This resource will continue to grow, with new studies and improvements added regularly.
Please note that HFDF does not necessarily endorse or support any policy arguments or specific assumptions made by the authors. HFDF commentary describes and summarizes the role this study plays in the scientific discourse and provides abbreviated notes.
Recently Posted Studies
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The effect of BNT162b2 SARS?CoV?2 mRNA vaccine on menstrual cycle symptoms in healthy women
Journal: Int J Gynaecol ObstetLead Author:
Lessans, et al.Original date of publication:
01/01/2023Keywords: adverse events, covid vaccination, fatigue, Johnson & Johnson, menstrual bleeding, menstrual cycle, Moderna, mRNA, Oxford, PfizerThis study addresses the well known (but initially supressed) menstrual issues after vaccination. 38% of participants reported menstrual changes, and almost a quarter (23%) had irregular bleeding after vaccination with mRNA injections.
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Premenstrual and menstrual changes reported after COVID-19 vaccination: The EVA project
Journal: Womens HealthLead Author:
Baena-Garcia, et al.Original date of publication:
01/01/2022Keywords: adverse events, covid vaccination, fatigue, Johnson & Johnson, menstrual bleeding, menstrual cycle, Moderna, mRNA, Oxford, PfizerMore than 3/4ths of women surveyed had changes to their menstrual cycle occur after mRNA injection (and other types)
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Investigating trends in those who experience menstrual bleeding changes after SARS-CoV-2 vaccination
Journal: Sci AdvLead Author:
Lee et al.Original date of publication:
07/15/2022Keywords: adverse events, covid vaccination, fatigue, Johnson & Johnson, menstrual bleeding, menstrual cycle, Moderna, mRNA, Oxford, PfizerThis study details the huge number of women who experienced significant changes to their menstrual cycle, including women who know longer were menstruating regularly. Increased bleeding and breakthrough bleeding were common.
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COVID-19 vaccines and autoimmune disorders: A scoping review
This high level study looked at all kinds of studies on auto-immune reactions after mRNA vaccination. these showed people with pre-existing issues had flares, and new onsets reported of multiple sclerosis, lupus, type 1 diabetes, rheumatoid arthritis, Graves’ disease, Hashimoto’s thyroiditis, and other conditions.
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COVID-19 vaccine induced Axillary and Pectoral Lymphadenopathy on PET scan
This study is a case report of a cancer patient whose condition worsened in a unique way at the point of injection.
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Autoimmune hepatitis triggered by SARS-CoV-2 vaccination
Case study of autoimmune hepatitis case emerging post mRNA vaccine








