Senate Hearing on COVID Vaccine Adverse Events; Study IDs Blood Clot Trigger
A Senate subcommittee heard testimony that mRNA COVID vaccines were considered the likely cause in 73.9% of post-vaccine deaths in a large autopsy series. Separately, NEJM research identified the K31E antibody mutation and adenovirus protein pVII as triggers of rare VITT blood clots. The findings may enable safer adenoviral vaccines.
The U.S. Senate’s Permanent Subcommittee on Investigations held a hearing titled "The Corruption of Science and Federal Health Agencies: How Health Officials Downplayed and Hid Myocarditis and Other Adverse Events Associated with the COVID-19 Vaccines," where top medical experts and legal voices testified. Dr Peter McCullough presented findings from a large autopsy series, stating that in 73.9% of examined post-vaccine deaths, mRNA COVID vaccines were considered the likely cause, a claim that has sparked intense debate in the medical community. Separately, a study published in the New England Journal of Medicine identified why some patients developed dangerous blood clots called vaccine-induced immune thrombocytopenia and thrombosis (VITT) after receiving certain COVID-19 vaccines or after natural adenovirus infection.
The study, led by researchers at McMaster University, found that a specific antibody mutation (K31E) can redirect the immune system to attack platelet factor 4 (PF4), triggering rare but serious clotting events known as VITT. The immune response that sets the stage for VITT is aimed at an adenovirus protein called protein VII (pVII), which closely resembles a region of the human blood protein PF4. In very rare cases, a single, specific mutation arises in one of the antibody-producing cells, changing one positively-charged amino acid to a negatively-charged amino acid. That tiny shift is enough to redirect the antibody targeting away from pVII and toward PF4 instead. Once the antibody binds PF4, it activates platelets and triggers the clotting and low platelet counts seen in VITT.
Crucially, the study detected the same K31E mutation in all VITT patient antibodies examined. When researchers reversed the mutation in lab-engineered antibodies, their dangerous activity disappeared, proving that this specific change is required for the complication to occur. The team uncovered the mechanism by sequencing antibodies from patients with VITT, mapping their structures with mass spectrometry, and engineering laboratory versions to watch how they behaved and mutated. They also confirmed the findings in a humanized mouse model, where the VITT antibody caused clotting, but the "back-mutated" version did not.
VITT can happen after a repeat exposure to adenovirus, whether from a vaccine or a natural infection, but only in people who have a certain inherited version of an antibody gene (IGLV3-21*02 or *03). Because this gene variant is found in up to 60 per cent of the population, it cannot by itself account for the ultrarare complication. The discovery answers long-standing questions about VITT: why adenoviral-vector vaccines and natural adenovirus infection can trigger it, why PF4 is the target (due to mimicry between pVII and PF4), why VITT is extraordinarily rare (it requires a specific, chance mutation in a predisposed person), and why incidence differs between vaccines and patient groups. By identifying the exact viral trigger and mutation mechanism, scientists can now redesign adenoviral vaccines to avoid this rare complication while preserving their effectiveness and broader public health benefits.