TY - JOUR
T1 - Different clinical features in Malawian outpatients presenting with COVID-19 prior to and during Omicron variant dominance
T2 - A prospective observational study
AU - Chibwana, Marah G.
AU - Thole, Herbert W.
AU - Anscombe, Cat
AU - Ashton, Philip M.
AU - Green, Edward
AU - Barnes, Kayla G.
AU - Cornick, Jen
AU - Turner, Ann
AU - Witte, Desiree
AU - Nthala, Sharon
AU - Thom, Chikondi
AU - Kanyandula, Felistas
AU - Ainani, Anna
AU - Mtike, Natasha
AU - Tambala, Hope
AU - N'goma, Veronica
AU - Mwafulirwa, Dorah
AU - Asima, Erick
AU - Morton, Ben
AU - Gmeiner, Markus
AU - Gundah, Zaziwe
AU - Kawalazira, Gift
AU - French, Neil
AU - Feasey, Nicholas
AU - Heyderman, Robert S.
AU - Swarthout, Todd D.
AU - Jambo, Kondwani C.
N1 - Publisher Copyright:
© 2023 Chibwana et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
PY - 2023/3/8
Y1 - 2023/3/8
N2 - 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. SARSCoV- 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.
AB - 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. SARSCoV- 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.
UR - http://www.scopus.com/inward/record.url?scp=85171424854&partnerID=8YFLogxK
U2 - 10.1371/journal.pgph.0001575
DO - 10.1371/journal.pgph.0001575
M3 - Article
AN - SCOPUS:85171424854
SN - 2767-3375
VL - 3
JO - PLOS global public health
JF - PLOS global public health
IS - 3
M1 - e0001575
ER -