Why are there so few (or so many) circulating coronaviruses?

Benjamin L. Rice, Daniel C. Douek, Adrian B. McDermott, Bryan T. Grenfell, C. Jessica E. Metcalf

Research output: Contribution to journalReview articlepeer-review

4 Scopus citations


Despite vast diversity in non-human hosts and conspicuous recent spillover events, only a small number of coronaviruses have been observed to persist in human populations. This puzzling mismatch suggests substantial barriers to establishment. We detail hypotheses that might contribute to explain the low numbers of endemic coronaviruses, despite their considerable evolutionary and emergence potential. We assess possible explanations ranging from issues of ascertainment, historically lower opportunities for spillover, aspects of human demographic changes, and features of pathogen biology and pre-existing adaptive immunity to related viruses. We describe how successful emergent viral species must triangulate transmission, virulence, and host immunity to maintain circulation. Characterizing the factors that might shape the limits of viral persistence can delineate promising research directions to better understand the combinations of pathogens and contexts that are most likely to lead to spillover.

Original languageEnglish (US)
Pages (from-to)751-763
Number of pages13
JournalTrends in Immunology
Issue number9
StatePublished - Sep 2021

All Science Journal Classification (ASJC) codes

  • Immunology and Allergy
  • Immunology


  • antigenic space
  • cross-reactivity
  • landscape of immunity
  • viral ecology


Dive into the research topics of 'Why are there so few (or so many) circulating coronaviruses?'. Together they form a unique fingerprint.

Cite this