After writing the post about quarantine and isolation, I wondered if it was possible to eradicate a disease using those methods.
It seems plausible. After all, if you stop infected or potentially infected people from coming into contact with others, the disease should fizzle out, right?
In practice, of course, it would be difficult. Even if you do manage to eradicate a disease within a certain population (“elimination”, in the lingo), it just takes one person barging in from elsewhere announcing “I don’t feel too hot” and you have another outbreak on your hands. And in our highly connected world, that’s all but guaranteed to happen.
So in practice, you’re unlikely to eliminate a disease anywhere unless you eliminate it everywhere, and, let’s face it, that’s not going to happen with coronavirus any time soon.
But in principle, could it be done? Could coronavirus be eradicated through self-isolation and quarantine?
Well, sort of, but that turns out that that’s the wrong question.
The question to ask, I discovered, is not so much “Can you eradicate a disease using self-isolation and quarantine?” as “Can you eradicate a disease?”
Only two diseases – smallpox and rinderpest – have been declared eradicated by the World Health Organization, and one of them is not even a human disease; it affects cattle.
There are, on the other hand, diseases that give the appearance of having been eradicated, in the sense that no humans are currently infected. SARS is one of these. During the 2002-3 epidemic, self-isolation and quarantine were used very effectively. They broke the chain of transmission, and now nobody has SARS. So doesn’t that mean that SARS has been eradicated?
Not really. The virus still exists, in research facilities and in bats (the animals we originally got it from). And from both of those reservoirs it could jump back into humans.
So although nobody has SARS anymore, it’s not really meaningful to say that it has been eradicated.
Given the impossibility – or in any case impracticability – of eradicating it, the best we can do is try and stop it entering the human population again.
How might it re-enter our population?
One way is a repeat of the first time around, from animals carrying the virus. So it is important to monitor potential spillover points, for example by regularly examining blood samples taken from animals at wet markets.
Another way is if there is a breach at research facilities. This is particularly worrying if the research in question is on “gain of function”, which aims to make diseases more dangerous, for example by making them more contagious, more resistant to antibiotics or better able to evade the immune system. In general, gain-of-function research is not driven by malicious motives; rather, its purpose is to look at how a disease might develop, allowing researchers to develop treatments and strategies for dealing with an outbreak before an outbreak happens. But it is controversial, because if you’re going to have researchers deliberately making viruses more dangerous, you want to know you can trust both the researchers and the protocols governing their work.
In fact, SARS has already escaped from research facilities a few times, although in all cases so far it has been contained. In 2003 a researcher in Singapore was infected by contaminated specimens and a researcher in Taiwan was infected by contaminated waste material. There was also a cluster of infections in 2004 when the virus escaped from the Institute of Virology in Beijing.
Also, in 2014, two and a half thousand vials of samples containing the SARS virus disappeared from the Institut Pasteur in Paris. The director general of the institute played down the severity of the incident, saying that the stringent security measures in place meant that the vials probably hadn’t left the building, and the most likely explanation was that they had been accidentally destroyed. He also hastened to add that even if they had been removed, they would almost certainly be harmless. All attempts to isolate the SARS virus from the samples had failed; what’s more, they had previously thawed for several days when the freezer in which they were stored broke down, an ordeal that the virus was unlikely to have survived.
So security measures at research facilities have to be tight and research activities have to be transparent and closely monitored.
And the main lesson from all of this is that we should try to make sure that the questions we’re asking are the right ones. Or, as Oliver Burkeman says in This Column Will Change Your Life, “Next time you’re trying to solve a problem, remember to check that the problem you’re solving is the problem you’ve actually got”.
(To be honest, I’m not completely sure that “Can you eradicate a disease?” is actually the right question, in the sense of helping solve a problem, but at least I learned something, and if I later find a question that seems righter, I will look into it.)
Where has SARS gone? The strange case of the disappearing coronavirus (Somatosphere)
The pieces of the puzzle of covid-19’s origin are coming to light (The Economist)
Where did the novel coronavirus come from? (The Economist)
France’s Institut Pasteur Under Fire Over Missing SARS Vials (Science)
Disease eradication: what does it take to wipe out a disease? (American Society for Microbiology)