Merck Settles Gardasil Lawsuits for $50 Million as New Study Identifies Strong POTS Signal
Peer-reviewed research, newly released court documents and expert testimony are renewing debate over the safety of Merck’s HPV vaccine and the need for greater transparency.
Merck has agreed to pay US $50 million to settle more than 200 lawsuits alleging that its Gardasil HPV vaccine caused serious autoimmune and neurological injuries in young people. Although the pharmaceutical giant continues to deny wrongdoing and maintains that Gardasil is safe and effective, the settlement comes as a new peer-reviewed study identifies postural orthostatic tachycardia syndrome (POTS) as the strongest safety signal associated with HPV vaccination in the U.S. vaccine injury reporting system.
Taken together, the settlement, newly released court documents and emerging scientific evidence are adding momentum to calls for more transparent safety monitoring and independent investigation of reported adverse events.
New Study Finds Strong Signal for POTS
Researchers from Xiamen University in China analyzed 77,909 reports associated with HPV vaccines submitted to the U.S. Vaccine Adverse Event Reporting System (VAERS) between 2006 and 2024.
Published in PLOS One, the researchers used four established pharmacovigilance methods to identify adverse events reported more frequently than expected.
Among their findings:
- POTS produced the strongest statistical safety signal identified in the analysis.
- Syncope (fainting) was the most frequently reported adverse event.
- Nearly 90% of reported adverse events occurred within 30 days of vaccination.
- More than two-thirds of reports involved females, and almost half involved individuals under 18—the primary age group targeted for HPV vaccination.
The authors concluded that the POTS signal warrants further investigation, while emphasizing that a statistical signal alone does not prove causation.
Critics Say the Findings Were Minimized
Despite identifying POTS as the strongest safety signal, the study devoted little discussion to the finding and concluded that HPV vaccines have an overall favourable safety profile.
Several independent scientists questioned that conclusion.
Children’s Health Defense Chief Scientific Officer Brian Hooker, Ph.D., said the attempts to minimize the findings were deeply troubling.
“The attempts to downplay POTS as a side effect of the HPV shot are criminal and the paper is expertly crafted to hide this very obvious signal in order to repeat the default ‘safe and effective’ lie,” Hooker said.
Independent researcher Cynthia Nevison, Ph.D., also questioned the authors’ conclusions.
“Again, the emphasis is on decreasing vaccine hesitancy and reassuring the public that safety is not an issue,” Nevison said. “On what basis are they claiming that ‘the overall safety … is favorable’? Such a statement requires a quantitative comparison of the number needed to harm vs. the number needed to treat for vaccine adverse events and HPV-related conditions, respectively, of comparable severity. Zhang et al. haven’t done this.”
Settlement Opens Door to Internal Merck Documents
The recent settlement also made thousands of pages of expert reports and internal evidence available to the public.
According to reports filed in the litigation, plaintiffs alleged that Merck failed to adequately warn physicians and the public about risks including POTS, autoimmune disorders and other neurological conditions following Gardasil vaccination.
While the settlement resolves most of the pending lawsuits, Merck did not admit liability, continuing to state that scientific evidence supports the vaccine’s safety and effectiveness.
Former Gardasil Trial Investigator Says Warnings Were Ignored
Among the documents released is an expert report from Dr. Jesper Mehlsen, a Danish clinical physiologist who served as principal investigator in several Merck-sponsored Gardasil clinical trials before later directing one of Denmark’s specialized government clinics established to evaluate patients reporting illnesses following HPV vaccination.
Mehlsen reported that clinicians began observing recurring patterns beginning in 2011, with previously healthy young people presenting symptoms including:
- Rapid heartbeat
- Severe fatigue
- Dizziness
- Brain fog
- Exercise intolerance
- Chest discomfort
As reports continued to increase, the Danish government established five regional clinics to evaluate patients with suspected vaccine-related illnesses.
After years of clinical investigation, Mehlsen concluded that Gardasil was the probable cause of POTS and an autoimmune condition resembling myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) in some patients.
His report also states that these concerns were shared with Merck but were not adequately investigated.
Questions About the Original Clinical Trials
Court documents also revived longstanding concerns about Gardasil’s clinical trial design.
Plaintiffs alleged that Merck used an aluminum-containing comparator rather than an inert saline placebo in many pre-licensure safety trials, potentially making adverse reactions more difficult to detect.
Expert reports further questioned whether important safety signals involving autonomic dysfunction and autoimmune disorders were sufficiently reflected in product warnings.
These allegations have not been proven in court, and Merck has consistently denied concealing safety information.
What Is POTS?
Postural orthostatic tachycardia syndrome (POTS) is a disorder affecting the autonomic nervous system, which regulates involuntary body functions such as heart rate and blood pressure.
Symptoms may include:
- Rapid heartbeat upon standing
- Dizziness
- Fainting
- Extreme fatigue
- Brain fog
- Exercise intolerance
- Digestive problems
- Chronic pain
For some patients, symptoms can become chronic and significantly impair daily functioning.
Why This Matters for Canadians
Across Canada, Gardasil continues to be offered through provincial school-based immunization programs, with public health authorities continuing to recommend HPV vaccination for eligible adolescents.
Health Canada states that it continuously monitors vaccine safety and encourages healthcare professionals and Canadians to report suspected adverse events.
However, the convergence of a peer-reviewed safety signal, expert testimony from a former Gardasil clinical trial investigator, and newly released court documents is prompting renewed calls for greater transparency, independent safety research, and continued evaluation of reported adverse events.
For Canadian families, the developments underscore the importance of informed consent, ongoing post-market safety surveillance, and ensuring that emerging evidence receives thorough and independent scientific review.
Sources:
Zhang Y, et al. Adverse events following HPV vaccine reported to the Vaccine Adverse Event Reporting System (2006–2024). PLOS One. 2026.
Brenda Baletti, Ph.D. New Study Strongly Links Merck’s Gardasil HPV Vaccine to POTS, but Authors Downplay Signal. CHD’s The Defender, June 26, 2026.
Brenda Baletti, Ph.D. Merck Ignored Gardasil Safety Warnings From Its Own Trial Investigator, Court Documents Reveal. CHD’s The Defender, June 16, 2026.
Carolyn Hendler, JD. Merck Settles Gardasil Vaccine Injury Lawsuit for $50 Million. The Vaccine Reaction, June 22, 2026.
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