New-Onset Complement-Mediated Thrombotic Microangiopathy during the COVID-19 Pandemic

Area of Science:

• Nephrology
• Immunology
• Infectious Diseases

Background:

• Coronavirus disease-19 (COVID-19), caused by SARS-CoV-2, is associated with pro-inflammatory states activating coagulation and complement cascades.
• Investigating the impact of the COVID-19 pandemic and SARS-CoV-2 vaccination on new-onset atypical hemolytic uremic syndrome (aHUS) and complement-mediated thrombotic microangiopathy (cTMA) is crucial.

Purpose of the Study:

• To determine the effect of the COVID-19 pandemic on patients with new-onset cTMA/aHUS within the Vienna TMA cohort.
• To assess whether COVID-19 infection or SARS-CoV-2 vaccination poses a greater risk for the initial manifestation of cTMA/aHUS.

Main Methods:

• Utilized the Vienna TMA cohort database to analyze the prevalence of COVID-19-related and SARS-CoV-2 vaccination-related aHUS/cTMA.
• Examined data from the first three years of the COVID-19 pandemic in a large, single-center cohort.

Main Results:

• Seven patients experienced their first aHUS/cTMA episode between March 2020 and May 2023.
• Three TMA episodes were linked to COVID-19 (n=1) or SARS-CoV-2 vaccination (n=2).
• Infections triggered one TMA episode (20%), while vaccinations triggered two (10%); no statistically significant difference was found (p=0.52).

Conclusions:

• Both SARS-CoV-2 vaccination and COVID-19 infection may trigger aHUS/cTMA in genetically predisposed individuals.
• COVID-19 infection may represent a stronger trigger for aHUS/cTMA compared to SARS-CoV-2 vaccines.
• The incidence of new aHUS cases did not change compared to the pre-pandemic era in this cohort.