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. 2023 May 31;12(1):2119.
doi: 10.4102/ajlm.v12i1.2119. eCollection 2023.

COVID-19 positive cases among asymptomatic individuals during the second wave in Ndola, Zambia

Jonathan Gwasupika  1 , Victor Daka  2 , Justin Chileshe  3 , Moses Mukosha  4 , Steward Mudenda  4 , Bright Mukanga  2 , Ruth L Mfune  2 , Gershom Chongwe  5
Affiliations

COVID-19 positive cases among asymptomatic individuals during the second wave in Ndola, Zambia

Jonathan Gwasupika et al. Afr J Lab Med. .

Abstract

Background: Coronavirus disease 2019 (COVID-19) is a worldwide public health concern for healthcare workers. About 80% of cases appear to be asymptomatic, and about 3% may experience hospitalisation and later die. Less than 20% of studies have looked at the positivity rate of asymptomatic individuals.

Objective: This study investigated the COVID-19 positivity rates among asymptomatic individuals during the second COVID-19 wave at one of Zambia's largest testing centre.

Methods: This was a retrospective cross-sectional study conducted on routine surveillance and laboratory data at the Tropical Diseases Research Centre COVID-19 laboratory in Ndola, Zambia, from 01 December 2020 to 31 March 2021. The study population was made up of persons that had tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection as a requirement for travel. Microsoft Excel was used to come up with an epidemiological curve of daily COVID-19 positive cases; proportions for gender were described using frequencies and percentages.

Results: A total of 11 144 asymptomatic individuals tested for SARS-CoV-2 were sampled for the study and 1781 (16.0%) returned positive results. The median age among those tested was 36 years (interquartile range: 29-46). Testing for COVID-19 peaked in the month of January 2021 (37.4%) and declined in March 2021 (21.0%). The epidemiological curve showed a combination of continuous and propagated point-source transmission.

Conclusion: The positivity rate of 16.0% among asymptomatic individuals was high and could imply continued community transmission, especially during January 2021 and February 2021. We recommend heightened testing for SARS-CoV-2 among asymptomatic individuals.

What this study adds: This study adds critical knowledge to the transmission of COVID-19 among asymptomatic travellers who are usually a key population in driving community infection. This knowledge is critical in instituting evidence-based interventions in the screening and management of travellers, and its control.

Keywords: COVID-19 disease; SARS-CoV-2; Zambia; asymptomatic individuals; positivity rate.

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Conflict of interest statement

The authors declare that they have no financial or personal relationships that may have inappropriately influenced them in writing this article.

Figures

FIGURE 1
FIGURE 1
Daily COVID-19-positive cases in asymptomatic travellers in Ndola, Zambia, December 2020 – March 2021.
See this image and copyright information in PMC

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