The origin of the Covid virus remains the pandemic’s biggest mystery. Did the virus jump to human beings from animals being sold at a food market in Wuhan, China? Or did the virus leak from a laboratory in Wuhan?
U.S. officials remain divided. The F.B.I. and the Department of Energy each concluded that a lab leak was the more likely cause. The National Intelligence Council and some other agencies believe that animal-to-human transmission is more likely. The C.I.A. has not taken a position. The question remains important partly because it can inform the strategies to reduce the chances of another horrific pandemic.
A recent Times Opinion essay — by Alina Chan, a biologist — refocused attention on the issue by making the case for the lab-leak theory. In today’s newsletter, I’ll try to lay out the clearest arguments for each side to help you decide which you consider more likely.
The case for natural transmission
1. It’s the norm.
Covid is part of the coronavirus family, so named because the virus contains a protein shaped like a spike. (Corona is the Latin word for crown.) In recent decades, the main way that coronaviruses have infected people is through animal-to-human transmission, which is also known as natural transmission.
The SARS virus, for example, appears to have jumped from civet cats, a relative of the mongoose, to humans in Asia in 2002. MERS seems to have jumped from camels to people in the Middle East around 2012. There is no previous example of a major coronavirus escaping a lab.
When you’re trying to choose between a historically common explanation for a phenomenon and an unusual explanation, the common one is usually the better bet.