Quicktake

Why the World Worries About a Covid-19 ‘Second Wave’ 

WHO: Do Not Question Whether There Will Be a Second Wave of Virus Infections
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As authorities the world over lift economy-crippling movement restrictions aimed at curbing coronavirus infections, the fear on everyone’s minds can be expressed in two words: second wave. The concern is that, once quelled, the pandemic will resurface with renewed strength, causing a repeat of rising infections, swamped health systems and orders for lockdowns. Rashes of new cases in pockets of Asia and the U.S. have added to the fears.

It’s not a scientific term with well-defined parameters. Rather, it’s used to refer to a subsequent, serious increase in cases that occurs after the original surge has ebbed in a given area. Pandemics are caused by new pathogens that the vast majority of humans have no immune protection against. That’s what allows them to become global outbreaks. Pandemics are uncommon, but influenza is one of the more frequent causes. What often happens is that a novel variant of flu virus spreads around the world and then recedes, kind of like a tsunami. A few months later, it comes back and spreads around the world, or large parts of it, again.