학술논문
Outcomes of laboratory-confirmed SARS-CoV-2 infection during resurgence driven by Omicron lineages BA.4 and BA.5 compared with previous waves in the Western Cape Province, South Africa
Document Type
article
Author
Mary-Ann Davies; Erna Morden; Petro Rousseau; Juanita Arendse; Jamy-Lee Bam; Linda Boloko; Keith Cloete; Cheryl Cohen; Nicole Chetty; Pierre Dane; Alexa Heekes; Nei-Yuan Hsiao; Mehreen Hunter; Hannah Hussey; Theuns Jacobs; Waasila Jassat; Saadiq Kariem; Reshma Kassanjee; Inneke Laenen; Sue Le Roux; Richard Lessells; Hassan Mahomed; Deborah Maughan; Graeme Meintjes; Marc Mendelson; Ayanda Mnguni; Melvin Moodley; Katy Murie; Jonathan Naude; Ntobeko A.B. Ntusi; Masudah Paleker; Arifa Parker; David Pienaar; Wolfgang Preiser; Hans Prozesky; Peter Raubenheimer; Liezel Rossouw; Neshaad Schrueder; Barry Smith; Mariette Smith; Wesley Solomon; Greg Symons; Jantjie Taljaard; Sean Wasserman; Robert J. Wilkinson; Milani Wolmarans; Nicole Wolter; Andrew Boulle
Source
International Journal of Infectious Diseases, Vol 127, Iss , Pp 63-68 (2023)
Subject
Language
English
ISSN
1201-9712
Abstract
Objectives: We aimed to compare the clinical severity of Omicron BA.4/BA.5 infection with BA.1 and earlier variant infections among laboratory-confirmed SARS-CoV-2 cases in the Western Cape, South Africa, using timing of infection to infer the lineage/variant causing infection. Methods: We included public sector patients aged ≥20 years with laboratory-confirmed COVID-19 between May 01-May 21, 2022 (BA.4/BA.5 wave) and equivalent previous wave periods. We compared the risk between waves of (i) death and (ii) severe hospitalization/death (all within 21 days of diagnosis) using Cox regression adjusted for demographics, comorbidities, admission pressure, vaccination, and previous infection. Results: Among 3793 patients from the BA.4/BA.5 wave and 190,836 patients from previous waves, the risk of severe hospitalization/death was similar in the BA.4/BA.5 and BA.1 waves (adjusted hazard ratio [aHR] 1.12; 95% confidence interval [CI] 0.93; 1.34). Both Omicron waves had a lower risk of severe outcomes than previous waves. Previous infection (aHR 0.29, 95% CI 0.24; 0.36) and vaccination (aHR 0.17; 95% CI 0.07; 0.40 for at least three doses vs no vaccine) were protective. Conclusion: Disease severity was similar among diagnosed COVID-19 cases in the BA.4/BA.5 and BA.1 periods in the context of growing immunity against SARS-CoV-2 due to previous infection and vaccination, both of which were strongly protective.