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What Does ‘Eliminating’ Covid-19 Mean, Anyway?
Understanding what elimination, eradication, and extinction mean to epidemiologists
Last Friday, the prestigious medical journal The Lancet published a stunning news headline: “New Zealand eliminates COVID-19.” In the piece, health journalist Sophie Cousins reported that the country had ended “community transmission of SARS-CoV-2” and recorded its first day of no new Covid-19 cases early last week — about a month after it had started its aggressive lockdown.
To the non-technical ear, this description of New Zealand’s very specific milestone may have seemed at odds with the way we usually think about “elimination.” Using the common definition of the word would suggest that the virus was completely wiped out from the island nation.
But the Lancet headline used “elimination” in the epidemiological sense, which means a very different thing, as I’ll explain below. The words “eradication” and “extinction” — which I hope we’ll be seeing in the news soon — are also used by epidemiologists to talk about infectious disease in very specific ways.
The following definitions were put forth by former CDC Deputy Director Dr. Walt Dowdle in a document for the CDC in 1999, though there’s plenty of nuanced scientific debate about how these terms are…
