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. Author manuscript; available in PMC: 2022 May 10.
Published in final edited form as: J Med Virol. 2022 Mar 23;94(7):2921–2924. doi: 10.1002/jmv.27722

Figure 1. Timeline for the emergence of the SARS-CoV-2 and its evolution and possible end outcome.

Figure 1.

The SARS-CoV-2 genome is closely related to the bat coronavirus. It crossed the interspecies barrier and was likely transmitted to animals in the live animal market in Wuhan, China. The live-animal market was subsequently transmitted to humans through direct contact with the virus. Later, the virus acquired the ability of human-to-human transmission through droplets, and due to increased travel patterns of humans led to a pandemic shortly thereafter. Due to chronic infection, colossal transmission and, vaccination, there was selection pressure on the virus that thus continued to evolve. This evolution continued until the virus reached maximum transmissibility, immune evasion, and low pathogenicity. Later in the evolution, virus may act as an attenuated natural vaccine and protect most of the infected individuals that may potentially lead to an end of the pandemic. The solid black arrow represents the confirmed transfer, whereas the dotted black arrow shows the possibility of viral transfer.