Where does COVID come from? The WHO investigation begins but faces challenges

The World Health Organization (WHO) has released its plan to investigate the origins of the COVID pandemic. The research will begin in Wuhan, the Chinese city where the novel SARS-CoV-2 coronavirus was first identified, and will expand across China and beyond. Tracing the path of the virus is important for preventing future viral relapses, but scientists say the WHO team faces a daunting task.

Most researchers think the virus originated in bats, but how it got to people is unknown. Other coronaviruses have passed from an intermediate animal host; for example, the virus that caused a severe acute respiratory syndrome (SARS) outbreak in 2002–2004 likely came to people from raccoon dogs (Nyctereutes procyonoides) or owls.

“Finding an animal with a SARS-CoV-2 infection is like looking for a needle in the largest haystack in the world. They may never find a “smoking bat” “or another animal, says Angela Rasmussen, a virologist at Columbia University in New York City.” It will be crucial for investigators to establish a collaborative relationship with scientists and government officials in China. “

Pinpointing the origins of a virus can take years if it can be done at all, and the investigation will also have to navigate the highly sensitive political situation between China and the United States. US President Donald Trump “called it a Chinese virus and the Chinese government is trying to do everything to prove it is not a Chinese virus,” said Linfa Wang, a virologist at Duke-National University of Singapore Medical School. The political blame game meant that crucial details about ongoing research in China were not made public, says Wang, who was part of the WHO mission that searched for the origin of SARS in China in 2003.

He hopes the situation with the new US administration will be less volatile. President-elect Joe Biden also said he will cancel Trump’s withdrawal from the WHO. Support from China and the United States will create “a much more positive environment for conducting research in this area,” says Wang.

Research begins in Wuhan

An international team of epidemiologists, virologists and researchers with expertise in public health, animal health and food safety will lead the WHO’s COVID-19 investigation. The agency has not released their names.

The team held its first virtual meeting, also with researchers in China on Oct.30, and is reviewing preliminary evidence and developing study protocols, WHO says. The initial phase of the investigation in Wuhan will likely be conducted by researchers already in China and international researchers will travel to the country after reviewing those findings, the agency says.

In Wuhan, researchers will take a closer look at the Huanan meat and animal market, which many of the first people diagnosed with COVID-19 had visited. What role the market played in the spread of the virus remains a mystery. According to a November 5 report on the terms of reference of the WHO mission, initial investigations sampled frozen animal carcasses from the market, but none found evidence of SARS-CoV-2. However, environmental samples, taken mainly from sewage and sewage, were positive for the virus. “Preliminary studies have not generated credible clues to narrow down the research area,” the report said.

The WHO mission will investigate wild and farmed animals sold at the market, including foxes, raccoons (Procyon lotor) and sika deer (Cervus nippon). They will also investigate other markets in Wuhan and track the animals’ travels across China and across the border. Investigators will prioritize animals that are known to be susceptible to the virus, such as cats and minks.

The team will also examine Wuhan medical records, to find out if the virus was spreading before December 2019. The researchers will interview the first people identified to have had COVID-19, to find out where they may have been exposed and will test blood samples from. medical personnel, laboratory technicians and agricultural workers gathered in the weeks and months before December, looking for antibodies against SARS-CoV-2. The report acknowledges that some of this work may already be underway in China.

Long-term plans

The initial investigation in Wuhan will inform long-term studies on the origins of the pandemic, which could lead investigators out of China. “The point at which an outbreak is first detected does not necessarily reflect where it began,” the WHO report says, noting preliminary reports of viral RNA detected in wastewater samples before the first cases were identified.

This statement could refer to a study¹, published on the medRxiv prepress server without peer review, which has retrospectively tested Spanish wastewater samples since March 2019 and found fragments of SARS-CoV-2, says Raina MacIntyre, epidemiologist at the University of New South Wales in Sydney, in Australia. “If this study was correct, we have to ask ourselves what the virus was like in Spain in March last year,” he says.

Plans to look beyond China make sense, as China’s extensive bat surveillance since the 2002 SARS outbreak has only identified a distant relative of SARS-CoV-2, Wang says. A growing number of experts think that SARS-CoV-2’s immediate or close ancestors are more likely to exist in bats outside of China, Wang says. He says the WHO team should examine bats and other wildlife across Southeast Asia for SARS-CoV-2 antibodies.

The investigation should also prioritize carnivorous mammals raised for fur, such as raccoon dogs and civets, which played a role in the SARS outbreak, says Martin Beer, a virologist at the Federal Research Institute for Animal Health in Riems. , in Germany. “It is surprising that there is no mention of these animals in the report and we have no information from China that these animals have been tested,” says Beer.

A WHO spokesperson says the mission will be science-driven and “will be open-minded, iterative, not ruling out any hypotheses that could help generate evidence and narrow the focus of research,” they said.