How does the virus SARS-CoV-2 infect humans and how might therapies be developed to treat this infection?

Bottom Line:

SARS-CoV-2 infects humans by using a ‘spike protein’ that enables the virus to enter human cells, so potential treatments could target this spike protein and be tested in animals that have similar cellular characteristics as humans.


Sun, J. et al. COVID-19: Epidemiology, Evolution, and Cross-Disciplinary Perspectives. Trends in Molecular Medicine (2020). DOI:

Date Published:

21 March 2020


SARS-CoV-2, the virus responsible for the COVID-19 pandemic, belongs to a class of viruses known as coronaviruses. Coronaviruses can infect many species other than humans, and as SARS-CoV-2 is similar to coronaviruses present in bats and pangolins, it is likely that this virus ‘jumped’ to humans from one of these species. A key viral structure that enables SARS-CoV-2 to infect humans is a ‘spike protein’ (S protein) present on the surface of the virus. During infection, the S protein gets cleaved into two subunits: S1, which binds to a protein present on human cells called ‘ACE2’; and S2, which fuses with the human cell membrane and allows the virus’s genetic material to enter the cell. Given the crucial role of the S protein in viral infectivity, drugs that prevent this protein from binding to ACE2 or fusing with the human cell membrane are promising treatment candidates that should be closely studied. Animals such as macaques, chimpanzees, and cats have an ACE2 receptor that is similar to human ACE2, which could be used as models to study whether viral infectivity is thwarted by certain drugs. One potential drug is enfuvirtide, which interferes with proper S2 formation and could therefore prevent the virus from fusing with the cell. While identifying viable animal models and drug candidates is an encouraging start, there is still much more research that must be done before potential treatments are deemed safe and effective in humans.

Summary by: Jacob Ferguson.