Introduction

While B.1.1.529 (Omicron) variants are highly transmissible and evade vaccine protection, population studies suggest that outcomes from infection are better compared with B.1.617.2 (Delta).

Objectives

To compare outcomesof maintenance hemodialysis (MHD) patients infected with Omicron vs. Delta variants.

Methods

A retrospective comparative study of MHD patients diagnosed with SARS-CoV-2 infection between June 2021 and May 2022. Outcomes were compared between those infected with Delta and Omicron variants. 

Results

26 subjects were diagnosed with the Delta variant and 71 with Omicron. Age groups were comparable, yet average number of vaccine doses was higher in the Omicron group. Over half of MHD infected with Omicron (57%) were asymptomatic during their illness. Infection severity was significantly worse among the Delta group: 50% developed severe or critical COVID-19 vs. 5% in the Omicron group (p<0.001). More subjects in the Delta group required oxygen or ventilatory support and COVID-19-specific therapies. 30-day mortality rate for the whole cohort was 5.2%. It was significantly higher among MHD in the Delta group than in the Omicron group (5/26, 19.2% vs. 0/71, p<0.001), as was 90-day mortality rate (5/26, 19.2% vs. 3/71, 4.2%, p=0.02). 

Conclusions

Among vaccinated MHD patients, infection with the Delta variant was associated with worse outcomes compared with Omicron.