The coronavirus that causes COVID-19 has killed more than 3,000 people globally and rattled world economies. This has heightened interest in how new contagious diseases spread, affect various populations, and eventually come under control.
Here are five facts about global diseases.
1. Pandemics have been around for centuries. The plague, or Black Death, killed millions in Europe and Asia in the 14th century. More recently, the Centers for Disease Control (CDC) says there have been at least four influenza pandemics in the 19th century, and three in the 20th century. The worst was the so-called Spanish Flu of 1918-19. It infected about 500 million people (one-third of the world's population) and killed about 50 million (including 675,000 in the U.S.). Other major outbreaks include the 1957 Asian Flu and 1968 Hong Kong Flu, each of which killed about 1 million globally; and the 2009 Swine Flu, which killed more than half a million.
2. Not all major outbreaks are pandemics, and not all pandemics are caused by viruses. The Ebola virus outbreak of 2014-16 caused misery in West Africa, and fear worldwide. But it was not considered a pandemic, because its geographic reach was limited. Conversely, the Black Death was a pandemic, but unlike the flu (and COVID-19 and Ebola), it was not caused by a virus.
3. People are paying more attention to the new coronavirus than to familiar-but-deadlier diseases such as flu. The COVID-19 virus is receiving far bigger headlines than influenza. But tens of thousands of Americans die each year from the flu while generating only routine alarm and attention. The Centers for Disease Control says about 23,000 Americans died from the flu in the 2015-16 season; 38,000 in 2016-17; 61,000 in 2017-2018; and 34,150 in 2018-19. (The last two flu seasons are preliminary estimates). It’s worth noting that there are vaccines (flu shots) for many strains of flu, but not yet for COVID-19.
4. The COVID-19 virus is somewhat similar, but not identical, to those that caused the SARS and MERS epidemics. All three are members of the coronavirus family, the CDC says. SARS (severe acute respiratory syndrome) began in Asia in 2002, eventually sickening 8,000 people and killing 774. MERS (Middle East respiratory syndrome) erupted in 2012. Through 2019, the WHO confirmed 2,494 MERS cases and 858 deaths worldwide. All three viruses began in animals such as cattle, camels, and bats, and spread to people, the CDC says.
5. The new virus could seriously hurt the global economy, but it’s too early to tell. With COVID-19 spreading throughout the world, experts are slashing earlier projections for global economic growth this year. The Organization for Economic Cooperation and Development has warned that global growth in 2020 could be halved if the infection spreads widely. But some economists say it’s hard to predict, largely because the global economy has changed so much in recent years. As The New York Times explained in early February, when SARS emerged in China in 2002, that country’s factories “were mostly churning out low-cost goods like T-shirts and sneakers for customers around the world.” Today, China – still the hardest-hit country – is “a principal element of the global economy, making the epidemic a substantially more potent threat to fortunes.” International companies, including many in the United States, depend heavily on Chinese customers and Chinese-made products.