Professor Dominic Dwyer is a medical virologist and infectious diseases physician at NSW Health Pathology's Institute of Clinical Pathology and Medical Research (ICPMR) at Westmead. In 2020, Prof Dwyer was selected by the World Health Organization to be the Australian representative on an international investigation into the origins of the SARS-CoV-2 virus. Prof Dwyer gives an insight into the findings from the investigation (and the politics which surrounded the study) which he will present at Pathology Update 2022.

The first confirmed cases of COVID-19 were initially linked to a wet market in the Chinese city of Wuhan, where animals were sold both dead and alive. Since the start of the pandemic, this theory that COVID-19 began through natural emergence from an animal to a human has widely been believed across the scientific community. However, suspicions have long remained that COVID-19 may have escaped, accidentally or otherwise, from a laboratory.

As part of the four-week investigation, Prof Dwyer and an international team of experts travelled to Wuhan to look at the clinical epidemiology (how COVID-19 spread among people), the molecular epidemiology (the genetic makeup of the virus and its spread), and the role that animals and the environment may have played. Prof Dwyer points out that the road to finding the source of an outbreak may be long, and this study was designed as just the first step towards understanding the origins of COVID-19.

“What we concluded is that the most likely cause of the COVID-19 outbreak was in fact a virus jumping from one animal species to another, possibly bat to pangolin, and then into humans. There has been much debate about whether SARS-CoV-2, the virus which causes COVID-19, originated in a laboratory, however we found no evidence to suggest this possibility. Whilst viruses certainly do escape from laboratories, this is actually very rare and not something that we believe was involved in this case.

“The Wuhan Institute of Virology has been at the centre of the ‘lab leak’ theory since the start of the pandemic, most likely because it has been studying bat coronaviruses for years, following the emergence of SARS in 2003. During our visit to this research facility, we found no evidence to suggest that they had SARS-CoV-2 prior to the start of the pandemic, making it extremely unlikely that it could be the source.

“What the evidence shows so far is that the virus was possibly circulating in Wuhan in mid-to-late November 2019. This is earlier than the first reports at the Wuhan wet market. We also know that not all of those first early COVID-19 cases had visited the market, including the man with the earliest reported onset date. This means that rather than being the source of COVID-19, it is likely that the market acted as an amplifying event. This means we need to look elsewhere to find the origins of the virus.

“It often takes a long time to figure out the origins of an outbreak and this investigation is just the beginning. In fact, part of our investigation was to work out what sort of studies need to be done next. For example, more studies are needed into frozen food products and their role in transmitting the virus. Whilst we considered the cold chain a possible pathway to transmission, we still don’t know how big a factor this was, if at all. Once we can find the source, we will be able to take steps collectively to reduce the risk of this happening again,” said Prof Dwyer.

Prof Dwyer will discuss findings from the investigation at Pathology Update 2022 from 1.05pm - 2.00pm on Friday 4 March.