SHM Converge Scientific Abstract ePoster Gallery-Vaccine Induced Hemophagocytic Lymphohistiocytosis: A Rare but Fatal Adverse Effect of the Pfizer-Biontech Covid-19 Vaccine

Vaccine Induced Hemophagocytic Lymphohistiocytosis: A Rare but Fatal Adverse Effect of the Pfizer-Biontech Covid-19 Vaccine

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This document is a medical case report describing a rare but serious adverse event: hemophagocytic lymphohistiocytosis (HLH) following the Pfizer-BioNTech COVID-19 vaccine. The patient was a 32-year-old woman with no prior medical history who developed 10 weeks of fevers, night sweats, and worsening shortness of breath beginning one week after her second vaccine dose. On admission, she had high fever, pallor, and reduced breath sounds, with marked laboratory abnormalities including anemia, thrombocytopenia, extreme ferritin elevation, elevated triglycerides, and liver enzyme abnormalities. Imaging showed bilateral ground-glass opacities and pleural effusions.<br /><br />Because her clinical picture strongly suggested HLH, clinicians started treatment with dexamethasone and etoposide. Bone marrow biopsy confirmed hemophagocytosis. Although she initially improved, she later developed refractory disease with recurrent fevers, neutropenia, and rising ferritin. She was then treated with higher-dose dexamethasone and emapalumab, which led to significant improvement and discharge.<br /><br />The report explains that HLH is a life-threatening hyperinflammatory syndrome caused by uncontrolled immune activation, often presenting with fevers, cytopenias, and hyperferritinemia. It emphasizes that infections, malignancy, and autoimmune causes should be ruled out before linking HLH to vaccination. The authors note that while vaccines remain safe and effective overall, healthcare providers should maintain a high level of suspicion for HLH in patients with unexplained inflammatory responses after recent COVID-19 vaccination. Early recognition and treatment are critical because untreated HLH is often fatal.

Asset Subtitle

Reema Shah

Meta Tag

Author List Dimple Shah, Reema Shah, Saumya Sharma, Spencer F. Weintraub

Category Clinical Vignettes

Concept Hemophagocytic Lymphohistiocytosis

Concept Fever

Concept Cytopenia

Concept Hyperferritinemia

Concept H-score

Distinguished Non-Finalist

Presenter Organization Northwell Health, Student at NYITCOM

Presenting Author Reema Shah

Track Adult

Keywords

hemophagocytic lymphohistiocytosis

HLH

Pfizer-BioNTech COVID-19 vaccine

adverse event

hyperferritinemia

dexamethasone

etoposide

emapalumab

bone marrow biopsy

cytopenias

Hemophagocytic Lymphohistiocytosis

Fever

Cytopenia

Hyperferritinemia

H-score