Different clinical features in Malawian outpatients presenting with COVID-19 prior to and during Omicron variant dominance: a prospective observational study

Chibwana, M. G. et al. (2023) Different clinical features in Malawian outpatients presenting with COVID-19 prior to and during Omicron variant dominance: a prospective observational study. PLoS Global Public Health, 3(3), e0001575. (doi: 10.1371/journal.pgph.0001575) (PMID:36963090) (PMCID:PMC10022204)

Abstract

The SARS-CoV-2 Omicron variant has resulted in a high number of cases, but a relatively low incidence of severe disease and deaths, compared to the pre-Omicron variants. Therefore, we assessed the differences in symptom prevalence between Omicron and pre-Omicron infections in a sub-Saharan African population. We collected data from outpatients presenting at two primary healthcare facilities in Blantyre, Malawi, from November 2020 to March 2022. Eligible participants were aged >1month old, with signs suggestive of COVID-19, and those not suspected of COVID-19, from whom we collected nasopharyngeal swabs for SARS-CoV-2 PCR testing, and sequenced positive samples to identify infecting-variants. In addition, we calculated the risk of presenting with a given symptom in individuals testing SARS-CoV-2 PCR positive before and during the Omicron variant-dominated period. Among 5176 participants, 6.4% were under 5, and 77% were aged 18 to 50 years. SARS-CoV-2 infection prevalence peaked in January 2021 (Beta), July 2021 (Delta), and December 2021 (Omicron). We found that cough (risk ratio (RR), 1.50; 95% confidence interval (CI), 1.00 to 2.30), fatigue (RR 2.27; 95% CI, 1.29 to 3.86) and headache (RR 1.64; 95% CI, 1.15 to 2.34) were associated with a high risk of SARS-CoV-2 infection during the pre-Omicron period. In comparison, only headache (RR 1.41; 95% CI, 1.07 to 1.86) did associate with a high risk of SARS-CoV-2 infection during the Omicron-dominated period. In conclusion, clinical symptoms associated with Omicron infection differed from prior variants and were harder to identify clinically with current symptom guidelines. Our findings encourage regular review of case definitions and testing policies to ensure case ascertainment.

• Item Type: Articles
• Additional Information: The study was financially supported by Wellcome in the form of a grant (220757/Z/20/Z). This study was also financially supported by the National Institute for Health Research (NIHR) in the form of a grant (16/136/46). This work was also supported by an MRC African Research Leader award (MR/T008822/1) to KCJ. This work was also supported by a Wellcome Strategic award (206545/Z/17/Z) to MLW.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Barnes, Dr Kayla

Creator Roles

Barnes, K. G.: Methodology, Writing – review and editing

• Authors: Chibwana, M. G., Thole, H. W., Anscombe, C., Ashton, P. M., Green, E., Barnes, K. G., Cornick, J., Turner, A., Witte, D., Nthala, S., Thom, C., Kanyandula, F., Ainani, A., Mtike, N., Tambala, H., N’goma, V., Mwafulirwa, D., Asima, E., Morton, B., Gmeiner, M., Gundah, Z., Kawalazira, G., French, N., Feasey, N., Heyderman, R. S., Swarthout, T. D., and Jambo, K. C.
• College/School: College of Medical Veterinary and Life Sciences > School of Infection & Immunity > Centre for Virus Research
• Journal Name: PLoS Global Public Health
• Publisher: Public Library of Science
• ISSN: 2767-3375
• ISSN (Online): 2767-3375
• Copyright Holders: Copyright © 2023 Chibwana et al.
• First Published: First published in PLoS Global Public Health 3(3): e0001575
• Publisher Policy: Reproduced under a Creative Commons License