Pandemic originsReport on COVID Origins Highlights Clues to Animal-Human Jump

Published 31 March 2021

The international team that traveled to Wuhan, China, to investigate the source of SARS-CoV-2 published its full findings Monday, which cover four possibilities, but the experts say a jump to humans from an intermediate animal carrier is the likeliest scenario based on promising clues. Release of the findings, however, prompted high-level calls for more transparency from China, including from the WHO’s director-general.

The international team that traveled to Wuhan, China, to investigate the source of SARS-CoV-2 published its full findings Monday, which cover four possibilities, but the experts say a jump to humans from an intermediate animal carrier is the likeliest scenario based on promising clues.

The World Health Organization (WHO)-led team published its 120-page report on the WHO’s website and fielded questions Monday. Release of the findings, however, prompted high-level calls for more transparency from China, including from the WHO’s director-general.

In other developments, global leaders and organizations on Monday called for an international “pandemic treaty” focusing on pandemic preparedness and response efforts to build a more robust global health system to protect future generations.

First Step in Exploring Source
The 10-person joint mission team traveled to China in January, spending nearly 4 weeks on the investigation. The group’s work was prompted by a May 2020 resolution by the World Health Assembly, which asked the WHO to identify the zoonotic source of the virus and how it passed to humans.

The source of the virus has been a flashpoint, playing out against the backdrop of political tensions between western nations and China. Some groups have questioned China’s transparency about the source of the outbreak, which led to speculation that the virus may have come from a lab.

At Monday’s briefing, Peter Ben Embarek, PhD, who led the WHO team, said the team identified four potential pathways, including a direct introduction from animals, a jump from an intermediate host, frozen food contamination, and an lab accident or leak. He said the team stuck to the hard facts about each possibility, while weighing the likelihood of each of them. WHO officials on Monday emphasized that all possibilities remain under consideration and that the investigation is the first step in exploring the source of the virus.

Thea Fisher, MD, PhD, from Nordsjaellands Hospital in Denmark, who was involved in the epidemiologic assessment, said the team looked at thousands of data points, including early cases that may signal unidentified earlier outbreaks. So far, no evidence of early substantial outbreaks has been found, and she said researchers will revisit the possibility when serology studies are conducted to look for any traces of the virus in the months preceding the outbreak.