Zoonotic spillover – speculations on the origin of COVID-19

As the majority of us know the first we heard of a potentially new respiratory disease in humans was on December 31st 2019 …

(New Year’s Eve!).  As I heard on CNN, the news was that there was a mysterious new disease causing an atypical pneumonia in Wuhan (Hubai Province), China. It wasn’t until February 2021 that the “world” took the threat of global disease seriously following spread to Italy and Spain; a global pandemic was announced by the WHO on 11 March 2020.  

After we figured out what is causing the disease – a novel coronavirus – the next question people started asking was where did it come from?  Given our previous experiences with SARS and MERS and the fact that the initial reports were coming from the Wuhan Seafood market, zoonosis arising from within the market was the prevailing hypothesis; pangolins were blamed! We know that SARS and MERS originated in bats and came to us through an intermediary host – civets and camels, respectively – so given some genetic analyses the pangolin hypothesis was not outlandish.  The fact is also, that the Wuhan Institute of Virology is also, as the name suggests, located in Wuhan. So, between the seafood market – wild animal trading – and virology institute there was much finger pointing, meme-making and general wild speculation.

So let’s look at some facts. Coronoviruses are zoonotic harboured by bats (the horseshoe bat is a prime reservoir), and there are seven coronaviruses that infect humans; four are endemic and cause mild cold-like symptoms.  The SARS and MERS coronaviruses as mentioned above have come to us via civets and camels, respectively.   So, there have been definitely been spillover events; so… a spillover event can not be discounted in that case of SARS-CoV-2. 

However, there is significant controversy, given the known research has been undertaken at Wuhan Institute of Virology.  Coronavirus research is definitely happening in the lab, there is published research and grants associated with the research. There are suggestions of gain of function experiments, which I don’t know much about, and which might get the “world expert” into some trouble in the US given that there is talk that such research may have been funded by the NIH; under the auspices of the “expert”.   Not sure about the “expert”, he is definitely good at politics – managed to stay at the top and relevant for a long time. 

Anyway, not the issue – the issue is whether gain-of-function research was performed in the lab.  It depends on many definitions – the most extreme would be “engineering” coronaviruses by tampering with genomes, and the most likely would be cell culture experiment in humans cells which may have increased the adaptability and fitness of the virus for human cells. Can’t be sure, but some good and interesting research would be performed at the Institute.

I am pretty certain we can totally eliminate the possibility of some kind of organised conspiracy to purposefully infect the world; if that was the case, a virus with an 1% case-fatality-rate would not be the way to do it.  There are many possible scenarios and IMO, there are two that have a higher probability than others.  This is pure speculation but my hypotheses are (fictional):

  1. SARS-like coronaviruses with mild symptoms spillover over constantly and circulate in people at low levels, mutating as they go… at some point around June-July in 2019 the fitter SARS-CoV-2 A lineage came about and then around September 2019mutated to the B lineage; these “new” lineages infected people and given that many people are asymptomatic and the majority only have mild disease, it was in mid-December where the number of people requiring treatment and in some cases hosptialization reached a critical number, prompting investigation and an announcement in late December.
  2. In a similar timeline, some “muppet” in the lab got accidentally infected with SARS-CoV-2 variant, spread to a co-worker or two and slowly the virus spread out;  again the critical threshold of sick people for investigation happened around mid-December leading to the announcement in late December.  Accidents in infectious disease laboratories are not new and I have first-hand experience at how accidents may happen in a “dangerous” lab;  I worked with radiation, mainly [125]I, for many years and always took the relevant precautions – fumehood, chest shield, double gloves etc.. on one occasion, despite all the good precautions I managed to contaminate my right hand with [125]I.  Luckily, an easily fixed situation but highlights that accidents can and do happen!

So, these are my leading two hypothesis at the moment … taking into account the facts that I understand … and remember, these are fictional scenarios made up in mind – feasible but could be way off the truth.  [I think it safe to say, that we could put silly conspiracy theories aside].

In the meantime in Australia, on a different topic altogether we have managed to annoy our neighbours (in particular China), and the French have removed their ambassadors; this is over a nuclear submarine agreement between the US, UK and Australia.  I’m not sure about the politics and I’m no expert in military defence but I know two things: 1) generally, the less war stuff the better, and 2) “AUKUS” (the acronym for the submarine allegiance)… sounds a bit stupid J!

Until next time …