Pandemic — COVID-19 & Its Aftermath

In December 2019, doctors at several hospitals in Wuhan, a city of eleven million people in central China's Hubei province, noticed clusters of patients with a strange pneumonia. CT scans showed a distinctive pattern of ground-glass opacities in the lungs. The patients were mostly connected to the Huanan Seafood Wholesale Market, a sprawling wet market where live animals were sold alongside fish and produce. By the end of the month, Chinese authorities had identified a novel coronavirus, later named SARS-CoV-2, as the cause.

The virus was not entirely unfamiliar. It belonged to the same family that produced SARS in 2003 and MERS in 2012. But this pathogen had a particular set of traits that made it far more dangerous at the population level: it spread through respiratory droplets and aerosols, it was transmissible before symptoms appeared, and a significant fraction of infected people showed mild or no symptoms at all, meaning they moved through the world spreading the virus without knowing they carried it. SARS had been more lethal per infection but far easier to contain because people got visibly sick before they became contagious.

The speed of the virus's spread, combined with images of overwhelmed hospitals in Wuhan and then Lombardy, pushed governments worldwide into a response without modern precedent. In March and April 2020, roughly half the world's population was placed under some form of Government-imposed restrictions on movement and economic activity intended to slow the transmission of an infectious disease. During the COVID-19 pandemic, lockdowns ranged from strict stay-at-home orders (as in Wuhan, Italy, and parts of India) to lighter restrictions on gatherings and business operations. The word entered common usage in 2020, though quarantine measures have been used against disease for centuries.. Schools closed. Offices emptied. Factories shut down. International borders slammed shut. Airlines grounded their fleets. The global economy shrank by about 3.5 percent in 2020, the worst peacetime contraction since the Great Depression.