BACKGROUND: Inequality is rife throughout South Africa. The first wave of COVID-19 may have affected people in lower socioeconomic groups worse than the affluent. The SARS-CoV-2 seroprevalence and the specificity of anti-SARS-CoV-2 antibody tests in South Africa is not known. METHODS: We tested 405 volunteers representing all socioeconomic strata from the workforce of a popular shopping and tourist complex in central Cape Town with the Abbott SARS-CoV-2 IgG assay. We assessed the association between antibody positivity and COVID-19 symptom status, medical history, and sociodemographic variables. We tested 137 serum samples from healthy controls collected in Cape Town prior to the COVID-19 pandemic, to confirm the specificity of the assay in the local population. RESULTS: Of the 405 volunteers tested one month after the first peak of the epidemic in Cape Town, 96(23.7%) were SARS-CoV-2 IgG positive. Of those who tested positive, 46(47.9%) reported no symptoms of COVID-19 in the previous 6 months. Seropositivity was significantly associated with living in informal housing, residing in a subdistrict with low income-per household, and having a low-earning occupation. The specificity of the assay was 98.54%(95%CI 94.82%-99.82%) in the pre-COVID controls. CONCLUSIONS: There is a high background seroprevalence in Cape Town, particularly in people of lower socioeconomic status. Almost half of cases are asymptomatic, and therefore undiagnosed by local testing strategies. These results cannot be explained by low assay specificity.
BACKGROUND: Inequality is rife throughout South Africa. The first wave of COVID-19 may have affected people in lower socioeconomic groups worse than the affluent. The SARS-CoV-2 seroprevalence and the specificity of anti-SARS-CoV-2 antibody tests in South Africa is not known. METHODS: We tested 405 volunteers representing all socioeconomic strata from the workforce of a popular shopping and tourist complex in central Cape Town with the Abbott SARS-CoV-2 IgG assay. We assessed the association between antibody positivity and COVID-19 symptom status, medical history, and sociodemographic variables. We tested 137 serum samples from healthy controls collected in Cape Town prior to the COVID-19 pandemic, to confirm the specificity of the assay in the local population. RESULTS: Of the 405 volunteers tested one month after the first peak of the epidemic in Cape Town, 96(23.7%) were SARS-CoV-2 IgG positive. Of those who tested positive, 46(47.9%) reported no symptoms of COVID-19 in the previous 6 months. Seropositivity was significantly associated with living in informal housing, residing in a subdistrict with low income-per household, and having a low-earning occupation. The specificity of the assay was 98.54%(95%CI 94.82%-99.82%) in the pre-COVID controls. CONCLUSIONS: There is a high background seroprevalence in Cape Town, particularly in people of lower socioeconomic status. Almost half of cases are asymptomatic, and therefore undiagnosed by local testing strategies. These results cannot be explained by low assay specificity.
Authors: Christopher A Martin; David R Jenkins; Jatinder S Minhas; Laura J Gray; Julian Tang; Caroline Williams; Shirley Sze; Daniel Pan; William Jones; Raman Verma; Scott Knapp; Rupert Major; Melanie Davies; Nigel Brunskill; Martin Wiselka; Chris Brightling; Kamlesh Khunti; Pranab Haldar; Manish Pareek Journal: EClinicalMedicine Date: 2020-07-17
Authors: Andrew Bryan; Gregory Pepper; Mark H Wener; Susan L Fink; Chihiro Morishima; Anu Chaudhary; Keith R Jerome; Patrick C Mathias; Alexander L Greninger Journal: J Clin Microbiol Date: 2020-07-23 Impact factor: 5.948
Authors: Eli S Rosenberg; James M Tesoriero; Elizabeth M Rosenthal; Rakkoo Chung; Meredith A Barranco; Linda M Styer; Monica M Parker; Shu-Yin John Leung; Johanne E Morne; Danielle Greene; David R Holtgrave; Dina Hoefer; Jessica Kumar; Tomoko Udo; Brad Hutton; Howard A Zucker Journal: Ann Epidemiol Date: 2020-06-17 Impact factor: 3.797
Authors: Silvia Stringhini; Ania Wisniak; Giovanni Piumatti; Andrew S Azman; Stephen A Lauer; Hélène Baysson; David De Ridder; Dusan Petrovic; Stephanie Schrempft; Kailing Marcus; Sabine Yerly; Isabelle Arm Vernez; Olivia Keiser; Samia Hurst; Klara M Posfay-Barbe; Didier Trono; Didier Pittet; Laurent Gétaz; François Chappuis; Isabella Eckerle; Nicolas Vuilleumier; Benjamin Meyer; Antoine Flahault; Laurent Kaiser; Idris Guessous Journal: Lancet Date: 2020-06-11 Impact factor: 79.321
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Authors: Daniel F Gudbjartsson; Gudmundur L Norddahl; Pall Melsted; Kristbjorg Gunnarsdottir; Hilma Holm; Elias Eythorsson; Asgeir O Arnthorsson; Dadi Helgason; Kristbjorg Bjarnadottir; Ragnar F Ingvarsson; Brynja Thorsteinsdottir; Steinunn Kristjansdottir; Kolbrun Birgisdottir; Anna M Kristinsdottir; Martin I Sigurdsson; Gudny A Arnadottir; Erna V Ivarsdottir; Margret Andresdottir; Frosti Jonsson; Arna B Agustsdottir; Jonas Berglund; Berglind Eiriksdottir; Run Fridriksdottir; Elisabet E Gardarsdottir; Magnus Gottfredsson; Olafia S Gretarsdottir; Steinunn Gudmundsdottir; Kjartan R Gudmundsson; Thora R Gunnarsdottir; Arnaldur Gylfason; Agnar Helgason; Brynjar O Jensson; Aslaug Jonasdottir; Hakon Jonsson; Thordur Kristjansson; Karl G Kristinsson; Droplaug N Magnusdottir; Olafur T Magnusson; Lovisa B Olafsdottir; Solvi Rognvaldsson; Louise le Roux; Gudrun Sigmundsdottir; Asgeir Sigurdsson; Gardar Sveinbjornsson; Kristin E Sveinsdottir; Maney Sveinsdottir; Emil A Thorarensen; Bjarni Thorbjornsson; Marianna Thordardottir; Jona Saemundsdottir; S Hjortur Kristjansson; Kamilla S Josefsdottir; Gisli Masson; Gudmundur Georgsson; Mar Kristjansson; Alma Moller; Runolfur Palsson; Thorolfur Gudnason; Unnur Thorsteinsdottir; Ingileif Jonsdottir; Patrick Sulem; Kari Stefansson Journal: N Engl J Med Date: 2020-09-01 Impact factor: 91.245
Authors: Sophie Uyoga; Ifedayo M O Adetifa; Henry K Karanja; James Nyagwange; Ambrose Agweyu; J Anthony G Scott; George M Warimwe; James Tuju; Perpetual Wanjiku; Rashid Aman; Mercy Mwangangi; Patrick Amoth; Kadondi Kasera; Wangari Ng'ang'a; Charles Rombo; Christine Yegon; Khamisi Kithi; Elizabeth Odhiambo; Thomas Rotich; Irene Orgut; Sammy Kihara; Mark Otiende; Christian Bottomley; Zonia N Mupe; Eunice W Kagucia; Katherine E Gallagher; Anthony Etyang; Shirine Voller; John N Gitonga; Daisy Mugo; Charles N Agoti; Edward Otieno; Leonard Ndwiga; Teresa Lambe; Daniel Wright; Edwine Barasa; Benjamin Tsofa; Philip Bejon; Lynette I Ochola-Oyier Journal: Science Date: 2020-11-11 Impact factor: 47.728
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