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The "Zero COVID" debate is one of the hottest controversies at the moment, with supporters on the defense, trying to explain exactly what they mean by the term.

Most epidemiologists and infectious disease experts strongly believe wiping SARS-CoV-2 from the face of the earth is unlikely -- but that's not what is meant by the concept, argued Deepti Gurdasani, PhD, of Queen Mary University of London, one of its most vocal proponents.

"Elimination is not eradication," Gurdasani . "No one is talking about eradication here."

During a recent ," Art Reingold, MD, professor of epidemiology at University of California Berkeley, opened the program by pointing out that the goals and terminology of the movement are unclear.

"What does 'Zero COVID' mean?" he asked. "Does it mean a global absence of COVID-19 in humans? Does it mean a global absence of SARS-CoV-2 transmission between humans? Does it mean a global absence of the virus? Or does it mean something else?"

"It's really important to get this straight," he said, "because I think the discussion that's going to follow would be very different depending on which of these definitions you're using."

Reingold noted that the lists several goals on its website, including getting to zero transmission, stopping the spread of COVID, and having a world without COVID.

"Those are not consistent messages, and they don't all mean the same thing to infectious disease epidemiologists," he said. (The group hasn't returned a 番茄社区app request for comment.)

What does mean something to those scientists are the , which lists four foundational principles for getting a handle on a pathogen:

• Control: a reduction in local case levels that requires an intervention to sustain
• Elimination: reducing local disease incidence to zero, with interventions still needed to maintain it
• Eradication: reducing disease incidence around the world to zero, with interventions no longer needed
• Extinction: the pathogen no longer exists in nature or in the lab

Many factors play into which of these outcomes are achievable, Reingold said, such as how easily the virus spreads, whether animal reservoirs exist, whether natural or vaccine-induced immunity is strong and how long it lasts, if immunity-evading variants pop up, and whether the political will to achieve such goals exists.

Gurdasani, who also spoke at the BMJ symposium, acknowledged that she's heard a few definitions, but that she focuses on elimination, or "getting cases to zero or near-zero in the community."

"We're not going to get rid of it entirely, globally, so it's a straw-man argument saying it's unachievable," Gurdasani said.

She has confronted critics that there's a "push from parts of the scientific community to portray Zero COVID as extreme or ignorant. It isn't. It has far more evidence behind it than most strategies. It has been achieved. It's certainly worth aiming for, even if not achieved, as it saves lives & livelihoods."

"Even if we don't achieve elimination, we'll protect society better than if we hadn't tried at all," she said during the BMJ symposium.

She noted that many nations have achieved "Zero COVID" and they're not all tiny island nations like New Zealand. China and Vietnam, for instance, have been very successful with squashing transmission and getting back to "normal" life.

Christina Pagel, PhD, of University College London, focused specifically on the U.K., saying that "Zero COVID" -- the elimination strategy -- "is the best approach right now" for that country, in terms of ensuring a future where cases are low and hospitals are not overwhelmed, by reducing the risk of creating a vaccine-resistant variant that forces another lockdown.

"Getting to near-zero is achievable," she said. "We'd be crazy to allow a high prevalence of disease this summer."

Participants generally seemed more willing to accept a "near-zero" definition, even though that varies slightly from the Dahlem Workshop classification of elimination.

"If it's near-zero, I am in 100% agreement with Deepti, as 'near' has quite some range," said John Ioannidis, MD, of Stanford University. "But is it really up to us, or is it up to the virus?"

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