Immunity, parasites, genetics and sex hormones: contributors to mild inflammatory responses in COVID-19?

Pan Afr Med J. 2020 May 15;35(Suppl 2):36. doi: 10.11604/pamj.supp.2020.35.2.23267. eCollection 2020.


The Coronavirus disease 2019 (COVID-19) pandemic has killed over two hundred thousand people by end of April, 2020. America and Europe top in deaths from COVID-19 whereas the numbers are lower in Africa for unclear reasons. Emerging evidence suggests the role of hyperactive immune responses characterised by high pro-inflammatory cytokines in severe cases of COVID-19 and deaths. In this perspective, we explore the possible factors that may contribute to mild inflammatory responses in some cases of COVID-19 by focusing on immune education, parasites, sex hormones and chronic diseases, as well as genetic tolerance. To build our perspective, evidence is also extracted from wild rodents due to their multi-tasking immune responses as a result of constant exposure to pathogens.

Keywords: COVID-19; cytokines; genetics; hormones; immunity; inflammation; mild symptoms; parasites.

MeSH terms

  • Animals
  • COVID-19 / immunology*
  • COVID-19 / physiopathology
  • Cytokines / immunology*
  • Gonadal Steroid Hormones / metabolism
  • Humans
  • Immunity / immunology
  • Inflammation / immunology
  • Inflammation / virology*
  • Parasitic Diseases / immunology
  • Parasitic Diseases / parasitology
  • Rodentia
  • Severity of Illness Index


  • Cytokines
  • Gonadal Steroid Hormones