High SARS-CoV-2 Seroprevalence among Healthcare Workers in Bamako, Mali

Anou M. Somboro*, Yacouba Cissoko, Issiaka Camara, Ousmane Kodio, Mohamed Tolofoudie, Etienne Dembele, Antieme C.G. Togo, Djibril M. Ba, Yeya Dit Sadio Sarro, Bocar Baya, Seydou Samake, Ibrahim B. Diallo, Alisha Kumar, Mohamed Traore, Bourahima Kone, Amadou Kone, Bassirou Diarra, Djeneba K. Dabitao, Mamadou Wague, Garan DaboSeydou Doumbia, Jane L. Holl, Robert L. Murphy, Souleymane Diallo, Almoustapha I. Maiga, Mamoudou Maiga, Sounkalo Dao

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


In Mali, a country in West Africa, cumulative confirmed COVID-19 cases and deaths among healthcare workers (HCWs) remain enigmatically low, despite a series of waves, circulation of SARS-CoV-2 variants, the country’s weak healthcare system, and a general lack of adherence to public health mitigation measures. The goal of the study was to determine whether exposure is important by assessing the seroprevalence of anti-SARS-CoV-2 IgG antibodies in HCWs. The study was conducted between November 2020 and June 2021. HCWs in the major hospitals where COVID-19 cases were being cared for in the capital city, Bamako, Mali, were recruited. During the study period, vaccinations were not yet available. The ELISA of the IgG against the spike protein was optimized and quantitatively measured. A total of 240 HCWs were enrolled in the study, of which seropositivity was observed in 147 cases (61.8%). A continuous increase in the seropositivity was observed, over time, during the study period, from 50% at the beginning to 70% at the end of the study. HCWs who provided direct care to COVID-19 patients and were potentially highly exposed did not have the highest seropositivity rate. Vulnerable HCWs with comorbidities such as obesity, diabetes, and asthma had even higher seropositivity rates at 77.8%, 75.0%, and 66.7%, respectively. Overall, HCWs had high SARS-CoV-2 seroprevalence, likely reflecting a “herd” immunity level, which could be protective at some degrees. These data suggest that the low number of cases and deaths among HCWs in Mali is not due to a lack of occupational exposure to the virus but rather related to other factors that need to be investigated.

Original languageEnglish (US)
Article number102
Issue number1
StatePublished - Jan 2022


  • Bamako
  • COVID-19
  • Healthcare workers
  • Mali
  • SARS-CoV-2
  • Seroprevalence
  • West Africa

ASJC Scopus subject areas

  • Infectious Diseases
  • Virology


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