Abstract
Background: The coronavirus disease 2019 (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 7 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants.
Methods: Our study includes individuals with positive SARS-CoV-2 reverse transcription polymerase chain reaction (RT-PCR) in the Washington Disease Reporting System with available viral genome data, from 1 December 2020 to 14 January 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.
Results: In total, 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% confidence interval [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 .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.
Conclusions: 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.
Keywords: COVID-19; SARS-CoV-2; hospitalization; vaccination; variants.
【저자키워드】 COVID-19, SARS-CoV-2, vaccination, Hospitalization, variants., 【초록키워드】 coronavirus disease, Coronavirus disease 2019, coronavirus, pandemic, Hospitalized, disease severity, hospital, Genomic surveillance, variant, Infection, Delta, Sex, risk, omicron, RT-PCR, variants, reverse transcription polymerase chain reaction, polymerase chain reaction, Cox proportional hazards model, Surveillance, Patient, Lineage, Gamma, Reporting, Alpha, Beta, age, reverse transcription, genomic, Analysis, viral genome, Washington, Chain Reaction, proportional hazards model, Support, retrospective cohort study, acute respiratory syndrome, 95% CI, acute respiratory syndrome coronavirus, no significant difference, acute respiratory syndrome coronavirus 2, 95% confidence interval, hazard ratio, individual, specimen, hazard ratios, positive, Effects, System, polymerase chain, resulting, collected, sequenced, include, Cox proportional hazard, 【제목키워드】 coronavirus 2, respiratory, Washington, Confirmed,