Complement Factors in COVID-19 Therapeutics and Vaccines

Trends Immunol. 2021 Feb;42(2):94-103. doi: 10.1016/ Epub 2020 Dec 13.


Complement is integral to a healthy functioning immune system and orchestrates various innate and adaptive responses against viruses and other pathogens. Despite its importance, the potential beneficial role of complement in immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been overshadowed by reports of extensive complement activation in severe coronavirus disease 2019 (COVID-19) patients. Here, we hypothesize that complement may also have a protective role and could function to enhance virus neutralization by antibodies, promote virus phagocytosis by immune cells, and lysis of virus. These functions might be exploited in the development of effective therapeutics and vaccines against SARS-CoV-2.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Adaptive Immunity
  • Animals
  • Antibodies, Viral / metabolism
  • COVID-19 / immunology*
  • COVID-19 Vaccines / immunology*
  • Complement Activation
  • Complement System Proteins / metabolism
  • Humans
  • Immunity, Innate
  • SARS-CoV-2 / physiology*


  • Antibodies, Viral
  • COVID-19 Vaccines
  • Complement System Proteins