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


Chibwana, Marah G ORCID: 0000-0002-8940-3855, Thole, Herbert W ORCID: 0000-0002-1507-1202, Anscombe, Cat, Ashton, Philip M, Green, Edward, Barnes, Kayla G, Cornick, Jen, Turner, Ann, Witte, Desiree ORCID: 0000-0002-2607-9816, Nthala, Sharon et al (show 17 more authors) (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-.

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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: Article
Uncontrolled Keywords: Clinical Research, Vaccine Related, Infectious Diseases, Prevention, Lung, Emerging Infectious Diseases, Biodefense, 2.1 Biological and endogenous factors, 2 Aetiology, Infection, 3 Good Health and Well Being
Divisions: Faculty of Health and Life Sciences
Faculty of Health and Life Sciences > Institute of Infection, Veterinary and Ecological Sciences
Depositing User: Symplectic Admin
Date Deposited: 19 Apr 2023 16:43
Last Modified: 12 Apr 2024 01:16
DOI: 10.1371/journal.pgph.0001575
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3169777
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