As I write, I’m in resort quarantine in Sydney, after coming back from Wuhan, China. There, I used to be the Australian consultant on the worldwide World Well being Group’s (WHO) investigation into the origins of the SARS-CoV-2 virus.
A lot has been mentioned of the politics surrounding the mission to research the viral origins of COVID-19. So it’s simple to neglect that behind these investigations are actual folks.
As a part of the mission, we met the person who, on December 8, 2019, was the primary confirmed COVID-19 case; he’s since recovered. We met the husband of a health care provider who died of COVID-19 and left behind a younger little one. We met the medical doctors who labored within the Wuhan hospitals treating these early COVID-19 circumstances, and discovered what occurred to them and their colleagues. We witnessed the influence of COVID-19 on many people and communities, affected so early within the pandemic, once we didn’t know a lot concerning the virus, the way it spreads, the best way to deal with COVID-19, or its impacts.
We talked to our Chinese language counterparts — scientists, epidemiologists, medical doctors — over the 4 weeks the WHO mission was in China. We have been in conferences with them for as much as 15 hours a day, so we turned colleagues, even associates. This allowed us to construct respect and belief in a means you couldn’t essentially do by way of Zoom or electronic mail.
That is what we discovered concerning the origins of SARS-CoV-2.
Animal origins, however not essentially on the Wuhan markets
It was in Wuhan, in central China, that the virus, now known as SARS-CoV-2, emerged in December 2019, unleashing the best infectious illness outbreak because the 1918-19 influenza pandemic.
Our investigations concluded the virus was most probably of animal origin. It most likely crossed over to people from bats, by way of an as-yet-unknown middleman animal, at an unknown location. Such “zoonotic” illnesses have triggered pandemics earlier than. However we’re nonetheless working to substantiate the precise chain of occasions that led to the present pandemic. Sampling of bats in Hubei province and wildlife throughout China has revealed no SARS-CoV-2 so far.
We visited the now-closed Wuhan moist market which, within the early days of the pandemic, was blamed because the supply of the virus. Some stalls on the market offered “domesticated” wildlife merchandise. These are animals raised for meals, corresponding to bamboo rats, civets and ferret badgers. There may be additionally proof some domesticated wildlife could also be vulnerable to SARS-CoV-2. Nonetheless, not one of the animal merchandise sampled after the market’s closure examined optimistic for SARS-CoV-2.
We additionally know not all of these first 174 early COVID-19 circumstances visited the market, together with the person who was identified in December 2019 with the earliest onset date.
Nonetheless, once we visited the closed market, it’s simple to see how an an infection may need unfold there. When it was open, there would have been round 10,000 folks visiting a day, in shut proximity, with poor air flow and drainage.
There’s additionally genetic proof generated in the course of the mission for a transmission cluster there. Viral sequences from a number of of the market circumstances have been similar, suggesting a transmission cluster. Nonetheless, there was some variety in different viral sequences, implying different unknown or unsampled chains of transmission.
A abstract of modelling research of the time to the newest widespread ancestor of SARS-CoV-2 sequences estimated the beginning of the pandemic between mid-November and early December. There are additionally publications suggesting SARS-CoV-2 circulation in numerous nations sooner than the primary case in Wuhan, though these require affirmation.
The market in Wuhan, ultimately, was extra of an amplifying occasion somewhat than essentially a real floor zero. So we have to look elsewhere for the viral origins.
Coronavirus: reside animals are burdened in moist markets, and burdened animals usually tend to carry illnesses
Frozen or refrigerated meals not dominated out within the unfold
Then there was the “chilly chain” speculation. That is the concept the virus may need originated from elsewhere by way of the farming, catching, processing, transporting, refrigeration or freezing of meals. Was that meals ice cream, fish, wildlife meat? We don’t know. It’s unproven that this triggered the origin of the virus itself. However to what extent did it contribute to its unfold? Once more, we don’t know.
A number of “chilly chain” merchandise current within the Wuhan market weren’t examined for the virus. Environmental sampling available in the market confirmed viral floor contamination. This may increasingly point out the introduction of SARS-CoV-2 by way of contaminated folks, or contaminated animal merchandise and “chilly chain” merchandise. Investigation of “chilly chain” merchandise and virus survival at low temperatures remains to be underway.
Might frozen meals transmit COVID-19?
Extraordinarily unlikely the virus escaped from a lab
Essentially the most politically delicate choice we checked out was the virus escaping from a laboratory. We concluded this was extraordinarily unlikely.
We visited the Wuhan Institute of Virology, which is a formidable analysis facility, and appears to be run effectively, with due regard to workers well being.
We spoke to the scientists there. We heard that scientists’ blood samples, that are routinely taken and saved, have been examined for indicators that they had been contaminated. No proof of antibodies to the coronavirus was discovered. We checked out their biosecurity audits. No proof.
We seemed on the closest virus to SARS-CoV-2 they have been engaged on — the virus RaTG13 — which had been detected in caves in southern China the place some miners had died seven years beforehand.
However all of the scientists had was a genetic sequence for this virus. They hadn’t managed to develop it in tradition. Whereas viruses definitely do escape from laboratories, that is uncommon. So, we concluded it was extraordinarily unlikely this had occurred in Wuhan.
British folks blame Chinese language authorities greater than their very own for the unfold of coronavirus
A workforce of investigators
Once I say “we”, the mission was a joint train between the WHO and the Chinese language well being fee. In all, there have been 17 Chinese language and ten worldwide specialists, plus seven different specialists and assist workers from numerous companies. We seemed on the medical epidemiology (how COVID-19 unfold amongst folks), the molecular epidemiology (the genetic make-up of the virus and its unfold), and the position of animals and the atmosphere.
The medical epidemiology group alone checked out China’s data of 76,000 episodes from greater than 200 establishments of something that might have resembled COVID-19 — corresponding to influenza-like diseases, pneumonia and different respiratory diseases. They discovered no clear proof of considerable circulation of COVID-19 in Wuhan in the course of the latter a part of 2019 earlier than the primary case.
The place to now?
Our mission to China was solely section one. We’re because of publish our official report within the coming weeks. Investigators will even look additional afield for information, to research proof the virus was circulating in Europe, as an illustration, earlier in 2019. Investigators will proceed to check wildlife and different animals within the area for indicators of the virus. And we’ll proceed to study from our experiences to enhance how we examine the subsequent pandemic.
No matter the origins of the virus, particular person folks with the illness are at the start of the epidemiology information factors, sequences and numbers. The long-term bodily and psychological results — the tragedy and nervousness — might be felt in Wuhan, and elsewhere, for many years to come back.
Sure, we want a world coronavirus inquiry, however not for petty political point-scoring
Dominic Dwyer doesn’t work for, seek the advice of, personal shares in or obtain funding from any firm or organisation that might profit from this text, and has disclosed no related affiliations past their educational appointment.