Characteristics and Outcomes of Hospitalized Patients in South Africa During the COVID-19 Omicron Wave Compared With Previous Waves

Abstract

On November 24, 2021, a SARS-CoV-2 variant of concern, Omicron (B.1.1.529),was identified in South Africa as responsible for a fourth wave of COVID-19.1,2 The high number of spike mutations has raised concerns about its ability to evade vaccine and spread.3,4 We assessed hospitalized patients with a positive SARS-CoV-2 test result during the fourth wave compared with previous waves.Methods | Netcare is a private health care group consisting of 49 acute care hospitals (>10 000 beds) across South Africa.South Africa has experienced 3 COVID-19 waves: (1) June to August 2020 (ancestral variant), (2) November 2020 to January 2021 (Beta), and (3) May to September 2021 (Delta).Cases again started to increase beginning November 15, 2021, coinciding with the identification of Omicron; as of December 7, 26% community positivity rates were reached.We identified the period when 26% positivity rates were reached in the previous waves (wave 1: June 14 to July 6, 2020; wave 2: December 1-23, 2020; wave 3: June 1-23, 2021) and compared them with the fourth wave (November 15 to December 7, 2021).For triage purposes, Netcare's policy is to test all admitted patients for COVID-19 with reverse transcriptasepolymerase chain reaction or, from wave 2 onward, a rapid antigen test obtained from a nasopharyngeal swab.All patients hospitalized with a positive COVID-19 result were included.Patient characteristics, need for oxygen supply and mechanical ventilation, admission to intensive care, length of stay (LOS), and mortality rates were extracted from the electronic administration system.Follow-up was through December 20, 2021.Categorical variables were compared between waves using a χ 2 test and continuous variables using 1-way analysis of variance (ANOVA).A 5% significance level (2-sided) was used. Analysis was performed using SAS version 9.4 for Windows (SAS Institute Inc).This study was approved by Pharma-ethics.All patients provided written informed consent.