Associations Between Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Variants and Risk of Coronavirus Disease 2019 (COVID-19) Hospitalization Among Confirmed Cases in Washington State: A Retrospective Cohort Study

Abstract

Background The COVID-19 pandemic is dominated by variant viruses; the resulting impact on disease severity remains unclear. Using a retrospective cohort study, we assessed the hospitalization risk following infection with seven SARS-CoV-2 variants. Methods Our study includes individuals with positive SARS-CoV-2 RT-PCR in the Washington Disease Reporting System with available viral genome data, from December 1, 2020 to January 14, 2022. The analysis was restricted to cases with specimens collected through sentinel surveillance. Using a Cox proportional hazards model with mixed effects, we estimated hazard ratios (HR) for hospitalization risk following infection with a variant, adjusting for age, sex, calendar week, and vaccination. Findings 58,848 cases were sequenced through sentinel surveillance, of which 1705 (2.9%) were hospitalized due to COVID-19. Higher hospitalization risk was found for infections with Gamma (HR 3.20, 95%CI 2.40-4.26), Beta (HR 2.85, 95%CI 1.56-5.23), Delta (HR 2.28 95%CI 1.56-3.34) or Alpha (HR 1.64, 95%CI 1.29-2.07) compared to infections with ancestral lineages; Omicron (HR 0.92, 95%CI 0.56-1.52) showed no significant difference in risk. Following Alpha, Gamma, or Delta infection, unvaccinated patients show higher hospitalization risk, while vaccinated patients show no significant difference in risk, both compared to unvaccinated, ancestral lineage cases. Hospitalization risk following Omicron infection is lower with vaccination. Conclusion Infection with Alpha, Gamma, or Delta results in a higher hospitalization risk, with vaccination attenuating that risk. Our findings support hospital preparedness, vaccination, and genomic surveillance.

Clinical and Virological Features of patients hospitalized with different types of COVID-19 vaccination in Mexico City

“…Moreover, previous studies analyzing large datasets have found differences in disease severity among patients infected with different lineages [44,45]. Nonetheless, studies with small datasets have failed in detecting such differences [46,47].…”

Exploring the Role of Serology Testing to Strengthen Vaccination Initiatives and Policies for COVID-19 in Asia Pacific Countries and Territories: A Discussion Paper

“…The emergence of virus mutations has resulted in concerns regarding the possible effects on transmissibility, severity of disease, immunity, vaccines' effectiveness, and the effectiveness of diagnostic methods. As shown in Table 1, regarding previously circulating VOCs (Alpha, Beta, Gamma, and Delta) [25], numerous studies have found an increase in transmissibility [29][30][31][32][33][34][35][36], risk of hospitalization [37][38][39][40][41][42][43], and risk of reinfection associated with these VOCs [34,[38][39][40]42,[44][45][46][47][48]. However, the vaccines' impact has varied depending on the metrics used to gauge effectiveness, such as protection against infection, symptomatic disease, and severe disease.…”

Clinical Performance Characteristics of the Swift Normalase Amplicon Panel for Sensitive Recovery of Severe Acute Respiratory Syndrome Coronavirus 2 Genomes

“…Viral whole-genome sequencing (WGS) of laboratory-confirmed SARS-CoV-2 isolates is frequently used in outbreak investigations, deployment of public health interventions, development of vaccines and therapeutics, and evaluating vaccine and antiviral effectiveness against emerging variants 4 , 5 , 6 , 10 , 11 , 12 , 13 , 14 , 15 . Specific SARS-CoV-2 variants have been associated with higher viral loads, lower vaccine effectiveness, and worse outcomes such as mortality 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 . Notably, B.1.1.7 has been associated with increased disease severity, prolonged hospitalization, and higher mortality risk 16 , 18 , 19 , 21 , 22 , 23 , 24 .…”

“…Specific SARS-CoV-2 variants have been associated with higher viral loads, lower vaccine effectiveness, and worse outcomes such as mortality 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 . Notably, B.1.1.7 has been associated with increased disease severity, prolonged hospitalization, and higher mortality risk 16 , 18 , 19 , 21 , 22 , 23 , 24 . Additionally, recent studies have shown poorer outcomes for patients infected with variants B.1.351 and P.1 23 , 25 .…”

“…Notably, B.1.1.7 has been associated with increased disease severity, prolonged hospitalization, and higher mortality risk 16 , 18 , 19 , 21 , 22 , 23 , 24 . Additionally, recent studies have shown poorer outcomes for patients infected with variants B.1.351 and P.1 23 , 25 . In a clinical setting, identification of specific viral mutations can aid in the selection of monoclonal therapies 26 , 27 , 28 , 29 , and viral sequencing can be used to monitor the accumulation of mutations during long-term viral replication in immunocompromised individuals 30 .…”