Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2023 Nov 17;23(1):272.
doi: 10.1186/s12874-023-02077-2.

Estimating the number of probable new SARS-CoV-2 infections among tested subjects from the number of confirmed cases

Y M Diarra #  1   2   3   4 , P M Wimba #  5   6   7   8   9 , P B Katchunga  7   8 , J Bengehya  10 , B Miganda  11 , M Oyimangirwe  7 , L Tshilolo  10 , S M Ahuka  12   13 , J Iwaz  5   6   14   15 , J F Étard  16   17 , R Écochard  5   6   14   15 , P Vanhems  5   6   15   9   18 , M Rabilloud  5   6   14   15
Affiliations

Estimating the number of probable new SARS-CoV-2 infections among tested subjects from the number of confirmed cases

Y M Diarra et al. BMC Med Res Methodol. .

Abstract

Objectives: In most African countries, confirmed COVID-19 case counts underestimate the number of new SARS-CoV-2 infection cases. We propose a multiplying factor to approximate the number of biologically probable new infections from the number of confirmed cases.

Methods: Each of the first thousand suspect (or alert) cases recorded in South Kivu (DRC) between 29 March and 29 November 2020 underwent a RT-PCR test and an IgM and IgG serology. A latent class model and a Bayesian inference method were used to estimate (i) the incidence proportion of SARS-CoV-2 infection using RT-PCR and IgM test results, (ii) the prevalence using RT-PCR, IgM and IgG test results; and, (iii) the multiplying factor (ratio of the incidence proportion on the proportion of confirmed -RT-PCR+- cases).

Results: Among 933 alert cases with complete data, 218 (23%) were RT-PCR+; 434 (47%) IgM+; 464 (~ 50%) RT-PCR+, IgM+, or both; and 647 (69%) either IgG + or IgM+. The incidence proportion of SARS-CoV-2 infection was estimated at 58% (95% credibility interval: 51.8-64), its prevalence at 72.83% (65.68-77.89), and the multiplying factor at 2.42 (1.95-3.01).

Conclusions: In monitoring the pandemic dynamics, the number of biologically probable cases is also useful. The multiplying factor helps approximating it.

Keywords: Africa.; COVID-19 testing; Reverse transcriptase polymerase chain reaction; SARS-CoV-2; Serology.

PubMed Disclaimer

Conflict of interest statement

None

References

    1. WHO COVID-19 Case definition. https://www.who.int/publications-detail-redirect/WHO-2019-nCoV-Surveillance_Case_Definition-2020.2. Last accessed: Sept. 2021.
    1. Kobia F, Gitaka J. COVID-19: are Africa’s diagnostic challenges blunting response effectiveness? AAS Open Res. 2020;3:4. doi: 10.12688/aasopenres.13061.1. - DOI - PMC - PubMed
    1. Nkuba AN, Makiala SM, Guichet E, Tshiminyi PM, Bazitama YM, Yambayamba MK, Kazenza BM, Kabeya TM, Matungulu EB, Baketana LK, Mitongo NM, Thaurignac G, Leendertz FH, Vanlerberghe V, Pelloquin R, Etard JF, Maman D, Mbala PK, Ayouba A, Peeters M, Muyembe JT, Delaporte E, Ahuka SM. High prevalence of anti-SARS-CoV-2 antibodies after the first wave of COVID-19 in Kinshasa, Democratic Republic of the Congo: results of a cross-sectional household-based survey. Clin Infect Dis. 2021;ciab515. 10.1093/cid/ciab515. - PMC - PubMed
    1. Mukwege D, Byabene AK, Akonkwa EM, Dahma H, Dauby N, Cikwanine Buhendwa JP, Le Coadou A, Montesinos I, Bruyneel M, Cadière GB, Vandenberg O, Van Laethem Y. High SARS-CoV-2 Seroprevalence in Healthcare Workers in Bukavu, Eastern Democratic Republic of Congo. Am J Trop Med Hyg. 2021;104:1526–30. doi: 10.4269/ajtmh.20-1526. - DOI - PMC - PubMed
    1. Scohy A, Anantharajah A, Bodéus M, Kabamba-Mukadi B, Verroken A, Rodriguez-Villalobos H. Low performance of rapid antigen detection test as frontline testing for COVID-19 diagnosis. J Clin Virol. 2020;129:104455. doi: 10.1016/j.jcv.2020.104455. - DOI - PMC - PubMed