Omicron B.1.1.529 variant infections associated with severe disease are uncommon in a COVID-19 under-vaccinated, high SARS-CoV-2 seroprevalence population in Malawi.

Autor:	Mseka UL; Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi.; Public Health Institute of Malawi, Lilongwe, Malawi., Mandolo J; Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi., Nyoni K; Public Health Institute of Malawi, Lilongwe, Malawi., Divala O; Public Health Institute of Malawi, Lilongwe, Malawi., Kambalame D; Public Health Institute of Malawi, Lilongwe, Malawi., Mapemba D; Public Health Institute of Malawi, Lilongwe, Malawi., Kamzati M; Public Health Institute of Malawi, Lilongwe, Malawi., Chibwe I; Public Health Institute of Malawi, Lilongwe, Malawi., Henrion MYR; Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi.; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom., Manda K; National Statistical Office, Zomba, Malawi., Thindwa D; Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi., Mvula M; Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi., Odala B; Public Health Institute of Malawi, Lilongwe, Malawi., Kamng'ona R; Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi., Dzinza N; National Statistical Office, Zomba, Malawi., Jere KC; Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi.; Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom.; Kamuzu University of Health Sciences (formerly University of Malawi, College of Medicine) Blantyre, Malawi., Feasey N; Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi.; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom., Ho A; University of Glasgow, Glasgow, United Kingdom., Amoah AS; London School of Hygiene and Tropical Medicine, London, United Kingdom.; Malawi Epidemiology and Intervention Unit, Lilongwe, Malawi., Gordon M; Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi.; Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom., Swarthout TD; NIHR Mucosal Pathogens Research Unit, Research Department of Infection, Division of Infection and Immunity, University College London, London, United Kingdom., Crampin A; University of Glasgow, Glasgow, United Kingdom.; London School of Hygiene and Tropical Medicine, London, United Kingdom.; Malawi Epidemiology and Intervention Unit, Lilongwe, Malawi., Heyderman RS; NIHR Mucosal Pathogens Research Unit, Research Department of Infection, Division of Infection and Immunity, University College London, London, United Kingdom., Kagoli M; Public Health Institute of Malawi, Lilongwe, Malawi., Chitsa-Banda E; Public Health Institute of Malawi, Lilongwe, Malawi., Mitambo C; Public Health Institute of Malawi, Lilongwe, Malawi., Phuka J; Kamuzu University of Health Sciences (formerly University of Malawi, College of Medicine) Blantyre, Malawi., Chilima B; Public Health Institute of Malawi, Lilongwe, Malawi., Kasambara W; Public Health Institute of Malawi, Lilongwe, Malawi., Jambo KC; Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi.; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.; Kamuzu University of Health Sciences (formerly University of Malawi, College of Medicine) Blantyre, Malawi., Chauma-Mwale A; Public Health Institute of Malawi, Lilongwe, Malawi.
Jazyk:	angličtina
Zdroj:	EClinicalMedicine [EClinicalMedicine] 2023 Feb; Vol. 56, pp. 101800. Date of Electronic Publication: 2022 Dec 30.
DOI:	10.1016/j.eclinm.2022.101800
Abstrakt:	Background: The B.1.1.529 (Omicron) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in the fourth COVID-19 pandemic wave across the southern African region, including Malawi. The seroprevalence of SARS-CoV-2 antibodies and their association with epidemiological trends of hospitalisations and deaths are needed to aid locally relevant public health policy decisions. Methods: We conducted a population-based serosurvey from December 27, 2021 to January 17, 2022, in 7 districts across Malawi to determine the seroprevalence of SARS-CoV-2 antibodies. Serum samples were tested for antibodies against SARS-CoV-2 receptor binding domain using WANTAI SARS-CoV-2 Receptor Binding Domain total antibody commercial enzyme-linked immunosorbent assay (ELISA). We also evaluated COVID-19 epidemiologic trends in Malawi, including cases, hospitalisations and deaths from April 1, 2021 through April 30, 2022, collected using the routine national COVID-19 reporting system. A multivariable logistic regression model was developed to investigate the factors associated with SARS-CoV-2 seropositivity. Findings: Serum samples were analysed from 4619 participants (57% female; 60% aged 18-50 years), of whom 878/3794 (23%) of vaccine eligible adults had received a single dose of any COVID-19 vaccine. The overall assay-adjusted seroprevalence was 83.7% (95% confidence interval (CI), 79.3%-93.4%). Seroprevalence was lowest among children <13 years of age (66%) and highest among adults 18-50 years of age (82%). Seroprevalence was higher among vaccinated compared to unvaccinated participants (1 dose, 94% vs. 77%, adjusted odds ratio 4.89 [95% CI, 3.43-7.22]; 2 doses, 97% vs. 77%, aOR 6.62 [95% CI, 4.14-11.3]). Urban residents were more likely to be seropositive than those from rural settings (91% vs. 78%, aOR 2.76 [95% CI, 2.16-3.55]). There was at least a two-fold reduction in the proportion of hospitalisations and deaths among the reported cases in the fourth wave compared to the third wave (hospitalisations, 10.7% (95% CI, 10.2-11.3) vs. 4.86% (95% CI, 4.52-5.23), p < 0.0001; deaths, 3.48% (95% CI, 3.18-3.81) vs. 1.15% (95% CI, 1.00-1.34), p < 0.0001). Interpretation: We report reduction in proportion of hospitalisations and deaths from SARS-CoV-2 infections during the Omicron variant dominated wave in Malawi, in the context of high SARS-CoV-2 seroprevalence and low COVID-19 vaccination coverage. These findings suggest that COVID-19 vaccination policy in high seroprevalence settings may need to be amended from mass campaigns to targeted vaccination of reported at-risk populations. Funding: Supported by the Bill and Melinda Gates Foundation (INV-039481). Competing Interests: All authors declare no conflict of interest. (© 2022 The Author(s).)
Databáze:	MEDLINE
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