Covid 19 coronavirus: The virus conundrum - eliminate or eradicate?

A group of 25 vaccinators have given and received their first Covid-19 vaccinations this afternoon. Video / Supplied

ANALYSIS:

What will become of Sars-CoV-2? Will it be a smallpox we are able to hunt down and eradicate; a measles we are able to eliminate in some parts of the world but not others; or an influenza, a virus we must go to war against every year?

The question has been increasingly exercising scientists and politicians in recent weeks and - without some basic ground rules - risks opening another destabilising divide.

In cartoon terms, there are two opposing and extremist camps: the Zero Covid brigade, who would have us locked down until the virus is wiped from the face of the Earth; and the Covid Sceptics who think the whole pandemic has somehow been overblown.

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"It starts with Zero Covid, then it'll be Zero Flu, Zero CO2 and so on and so forth. Pandora's box has opened," opines one Twitter warrior. The truth is, no one can yet be sure where Sars-CoV-2 is headed and the degree to which we can influence its trajectory is much exaggerated.

The late Dr Donald Henderson, the man who spearheaded the smallpox eradication programme, noted some viruses are simply more susceptible to eradication than others. In a 2013 interview, he said: "From my examination of the characteristics and needs for eradicating other diseases, each has prominent features that makes it far more difficult than smallpox. With smallpox, we had a vaccine so heat stable that teams travelled in the field without refrigeration devices."

In scientific terms, eradication means chasing it down to such an extent that there are no further cases or transmission anywhere in the world. We managed it with smallpox and are on the brink of doing it with polio, but that's it.

Elimination, on the other hand, has a different objective. When scientists set about eliminating a disease they aim to reduce cases to zero or thereabouts in a given geography - and this we have been much more successful with. In many nations, diseases including measles, mumps, cholera, typhoid, trachoma and tuberculosis can be said to have been successfully eliminated.

A Covid-19 elimination strategy, like the one implemented in New Zealand, seeks to reduce cases to zero or thereabouts in a given geography. Photo / Getty Images

Might it be possible to permanently eliminate Sars-CoV-2 in countries like Britain? Much will depend on the performance of vaccines and the ability of the virus to evolve to evade them.

Experts across the world are genuinely flabbergasted by the apparent success of the new mRNA-based Pfizer and Moderna jabs. The super-high efficacy levels recorded in trials appear to be holding up in the real world and data released by Israel last week suggests they may also all but cut out transmission of the virus.

On the other hand, the virus is showing signs of the sort of drift seen with seasonal flu.

"We're not going to eliminate [Covid] globally so we won't eliminate it here," said Professor Neil Ferguson of Imperial College London last week. "I would like to see this virus become like influenza and managed in similar ways."

Devi Sridhar, professor of global public health at Edinburgh University Medical School, does not disagree. She too thinks the virus is endemic and that eradication is, for the moment at least, nothing more than a pipe dream. But for Sridhar, it is a mistake - "a fundamental error" - to equate suppression of the virus with a loss of individual freedoms.

Professor Devi Sridhar says it is a mistake to equate an elimination strategy with the loss of individual freedoms. Photo / Michael Craig

"The higher your numbers, the less freedom you have. The lower your numbers, the more freedom you have," she says, pointing to countries which made early short-term sacrifices for longer-term gains.

"The whole puzzle of Covid has always been, 'how do you keep your numbers low and do it in a way that keeps you out of harsh lockdowns like the one we're in?'" she says.

Although it was forcefully rejected at the outset of the pandemic in Britain, this is the view now dominant in Downing Street and much of the rest of Europe.

A policy of suppression has taken over from mitigation because that approach has so obviously failed.