https://www.science.org/content/article/why-many-scientists-say-unlikely-sars-cov-2-originated-lab-leak
During the first year of the COVID-19 pandemic, the “lab leak” theory
gained little traction. Sure, U.S. President Donald Trump suggested
SARS-CoV-2 originated in a laboratory in Wuhan, China—and called it “the China virus”—but
he never presented evidence, and few in the scientific community took
him seriously. In fact, early in the pandemic, a group of prominent
researchers dismissed lab-origin notions as “conspiracy theories” in a
letter in The Lancet.
A report from a World Health Organization (WHO) “joint mission,” which
sent a scientific team to China in January to explore possible origins
with Chinese colleagues, described a lab accident as “extremely unlikely.”
But this spring, views began to shift. Suddenly it seemed that the
lab-leak hypothesis had been too blithely dismissed. In a widely read
piece, fueled by a “smoking gun” quote from a Nobel laureate, a veteran
science journalist accused scientists and the mainstream media of
ignoring “substantial evidence” for the scenario. The head of WHO openly pushed back against the joint mission’s conclusion, and U.S. President Joe Biden
ordered the intelligence community to reassess the lab-leak
possibility. Eighteen scientists, including leaders in virology and
evolutionary biology, signed a letter published in Science in May that called for a more balanced appraisal of the “laboratory incident” hypothesis.
Yet behind the clamor, little had changed. No breakthrough studies have been published. The highly anticipated U.S. intelligence review,
delivered to Biden on 24 August, reached no firm conclusions, but
leaned toward the theory that the virus has a natural origin.
Fresh evidence that would resolve the question may not emerge anytime
soon. China remains the best place to hunt for clues, but its relative
openness to collaboration during the joint mission seems to have
evaporated. Chinese officials have scoffed at calls from Biden and WHO
Director-General Tedros Adhanom Ghebreyesus for an independent audit of
key Wuhan labs, which some say should include an investigation of
notebooks, computers, and freezers. Chinese vice health minister Zeng Yixin
said such demands show “disrespect toward common sense and arrogance
toward science.” In response to the increasing pressure, China has also
blocked the “phase 2” studies outlined in the joint mission’s March
report, which could reveal a natural jump between species.
Despite the impasse, many scientists say the existing
evidence—including early epidemiological patterns, SARS-CoV-2’s genomic
makeup, and a recent paper about animal markets in Wuhan—makes it far
more probable that the virus, like many emerging pathogens, made a
natural “zoonotic” jump from animals to humans.
