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[Preprint]. 2021 Mar 12:2021.03.08.21253009.
doi: 10.1101/2021.03.08.21253009.

Seroprevalence of anti-SARS-CoV-2 IgG antibodies in Juba, South Sudan: a population-based study

Kirsten E Wiens  1 , Pinyi Nyimol Mawien  2 , John Rumunu  2 , Damien Slater  3 , Forrest K Jones  1 , Serina Moheed  3 , Andrea Caflish  4 , Bior K Bior  2 , Iboyi Amanya Jacob  2 , Richard Lino Loro Lako  2 , Argata Guracha Guyo  5 , Olushayo Oluseun Olu  5 , Sylvester Maleghemi  5 , Andrew Baguma  5   6 , Juma John Hassen  5 , Sheila K Baya  5 , Lul Deng  2 , Justin Lessler  1 , Maya N Demby  1 , Vanessa Sanchez  3 , Rachel Mills  3 , Clare Fraser  3 , Richelle C Charles  3   7 , Jason B Harris  3   8 , Andrew S Azman  1   9   10 , Joseph F Wamala  5
Affiliations

Seroprevalence of anti-SARS-CoV-2 IgG antibodies in Juba, South Sudan: a population-based study

Kirsten E Wiens et al. medRxiv. .

Update in

  • Seroprevalence of Severe Acute Respiratory Syndrome Coronavirus 2 IgG in Juba, South Sudan, 20201.
    Wiens KE, Mawien PN, Rumunu J, Slater D, Jones FK, Moheed S, Caflisch A, Bior BK, Jacob IA, Lako RL, Guyo AG, Olu OO, Maleghemi S, Baguma A, Hassen JJ, Baya SK, Deng L, Lessler J, Demby MN, Sanchez V, Mills R, Fraser C, Charles RC, Harris JB, Azman AS, Wamala JF. Wiens KE, et al. Emerg Infect Dis. 2021 Jun;27(6):1598-1606. doi: 10.3201/eid2706.210568. Emerg Infect Dis. 2021. PMID: 34013872 Free PMC article.

Abstract

Background: Relatively few COVID-19 cases and deaths have been reported through much of sub-Saharan Africa, including South Sudan, although the extent of SARS-CoV-2 spread remains unclear due to weak surveillance systems and few population-representative serosurveys.

Methods: We conducted a representative household-based cross-sectional serosurvey in Juba, South Sudan. We quantified IgG antibody responses to SARS-CoV-2 spike protein receptor-binding domain and estimated seroprevalence using a Bayesian regression model accounting for test performance.

Results: We recruited 2,214 participants from August 10 to September 11, 2020 and 22.3% had anti-SARS-CoV-2 IgG titers above levels in pre-pandemic samples. After accounting for waning antibody levels, age, and sex, we estimated that 38.5% (32.1 - 46.8) of the population had been infected with SARS-CoV-2. For each RT-PCR confirmed COVID-19 case, 104 (87-126) infections were unreported. Background antibody reactivity was higher in pre-pandemic samples from Juba compared to Boston, where the serological test was validated. The estimated proportion of the population infected ranged from 30.1% to 60.6% depending on assumptions about test performance and prevalence of clinically severe infections.

Conclusions: SARS-CoV-2 has spread extensively within Juba. Validation of serological tests in sub-Saharan African populations is critical to improve our ability to use serosurveillance to understand and mitigate transmission.

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Conflict of interest statement

Conflicts of interest

The authors declare no conflicts of interest.

Figures

Figure 1.
Figure 1.. Number of weekly SARS-CoV-2 tests and COVID-19 cases reported in Juba.
Weekly SARS-CoV-2 PCR tests performed from the week of May 3, 2020 to the week of October 30, 2020 in Juba. Grey bars show number of tests conducted per week, and red bars show the number of those tests that were positive for SARS-CoV-2. The first COVID-19 case was identified on April 2 and confirmed on April 4, 2020 [21].
Figure 2.
Figure 2.. Impact of assumptions on seroprevalence and ratio of reported to unreported infections.
a) Impact of assumed percent of infections that are mild on adjusted seroprevalence. Dashed line represents unadjusted seropositivity at 22.3%. b) Impact of assumed percent of infections on the ratio of implied unreported infections to reported infections, based on a total of 1,873 confirmed COVID-19 cases in Juba by August 31, 2020 and an approximate population in Juba of 510,000. Points represent mean adjusted seroprevalence or ratio of unreported infections and error bars represent 95% Credible Interval.
See this image and copyright information in PMC

References

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