The global Covid-19 pandemic may yet become the worst in modern history. Already there are more than 175 million cases and 3.8 million deaths.
As quickly as the pandemic was upon us, so too has been the response – the rapid implementation of new technologies to drive public health, novel approaches to vaccines, and the continuous courage and commitment of our healthcare workers.
But with the universal collaboration of those working to fight the virus comes others who have been unedifying and downright mistaken in their approach – the rejection or lack of scientific advice, prioritization of economic considerations over public health, social media manipulation, and the movement towards an ideological left versus right battle.
Swirling around these issues is the drive to understand the origins of Sars-CoV-2. Yes, it is crucial to find out what happened in 2019 in the months leading up to the explosive spread of the virus in China and globally, not for the sake of reproach, but to guide preparations for the next time around. And rest assured, there will be future pandemics.
Based on nearly all emerging human viruses of the last 50 years (including Sars in 2003 and Mers in 2012), animals are the likely source. By virtue of their ecology, bats play a special role, not just with coronaviruses, but with Ebola, Hendra, and others. According to the recent World Health Organization China study, the animal origins pathway is the most logical, but the “gotcha” evidence still eludes in what can take years.
The “lab leak” theories for Covid-19 range from accidental to deliberate and even state-sponsored. These are easy claims to make, comprehensible to everyone, part of popular culture (think Will Smith as a virologist in the film I am Legend, trusty canine by his side, an AK-47 and vaccine in hand) and catering to political discourse.
Accidental human infections in research laboratories have happened previously, but fortunately rarely. For a leak to occur, the virus must be present in the laboratory already and there would have to be a breakdown of usual regulated laboratory procedures around sample collection and preparation. For further spread, the infected worker must transmit the virus to close contacts and through them to the wider community. There is currently no clear evidence that any of these steps have happened. Even if these events had occurred, the virus still originated from animals.
It goes without saying that research laboratories are involved in searching for unusual pathogens, grow novel viruses for further work, and perform disease and vaccine studies. Knowing their importance in emerging infections, bat viruses research is carried out in laboratories worldwide. The bat virus discovered by Wuhanese researchers most closely related to Sars-CoV-2 (although too distant to be the “parent” virus), RaTG13, is only a genetic sequence and has not been grown in the laboratory.
Accidental leak from “gain of function” studies has also been floated as the origin of the virus. These studies involve altering the virus’s genetic make-up to increase its disease potential or spread, with the aim of better understanding future pandemics and developing vaccines.
Such work, sometimes controversial and usually highly regulated, has been performed in specialized laboratories in the US, China, and Europe. Claims have been made about specific features of the virus (the furin cleavage and receptor-binding sites) being evidence of genetic manipulation, however, these features are also naturally present in coronaviruses from bats and other animals.
Commentary about nefarious uses of “gain of function” or other secret work to weaponize viruses has also circulated. Such theories are easy to state, but difficult to verify without a whistleblower or similar dramatic evidence. Besides, the use of Sars-Sars-CoV-2 as a bioweapon is non-practical. Most people with Covid-19 make a full recovery, transmission is difficult to manipulate, and prior to its emergence, there would have been no vaccines or antiviral drugs to protect the guilty party.
An intelligence agency report stated three laboratory workers in Wuhan presented to hospital with undiagnosed respiratory illnesses or pneumonia before December 2019. Any evidence should be made available for an open investigation. Hospitalization with Covid-19 pneumonia occurs in only a modest proportion of infections, so one might assume that many other milder cases were circulating at the time. As outlined in the WHO report, there is no strong evidence of Sars-CoV-2 circulating in Wuhan well prior to December 2019, although the report clearly states that more work is needed.
No potentially reasonable theories have been rejected by the WHO report – the WHO itself stated that all hypotheses on the origins of Covid-19 remain on the table. The more people squabble over this issue, the longer it will take to get the science done. However, evidence from all sources must be gathered, verified, and used to guide further work. Evidence gathering must be done collaboratively across scientific disciplines (public health, animal health, plant health and the environment) and across international borders. This is everyone’s responsibility.
Professor Dominic Dwyer is a medical virologist and member of the World Health Organisation – China Joint Study Team on the Origins of Sars-CoV-2