How canceled events and self-quarantines save lives, in one chart

This is how we all help slow the spread of coronavirus.

by Eliza Barclay and Dylan Scott

The main uncertainty in the coronavirus outbreak in the United States now is how big it will get, and how fast. The Centers for Disease Control and Prevention’s Nancy Messonnier told reporters on March 9, “many people in the US will at some point, either this year or next, get exposed to this virus.”

According to infectious disease epidemiologist Marc Lipsitch at Harvard, it’s “plausible” that 20 to 60 percent of adults will be infected with Covid-19 disease. So far, 80 percent of cases globally have been mild, but if the case fatality rate is around 1 percent (which several experts say it may be), a scenario is possible of tens or hundreds of thousands of deaths in the US alone.

Yet the speed at which the outbreak plays out matters hugely for its consequences. What epidemiologists fear most is the health care system becoming overwhelmed by a sudden explosion of illness that requires more people to be hospitalized than it can handle. In that scenario, more people will die because there won’t be enough hospital beds or ventilators to keep them alive.

A disastrous inundation of hospitals can likely be averted with protective measures we’re now seeing more of — closing schools, canceling mass gatherings, working from home, self-quarantineself-isolation, avoiding crowds — to keep the virus from spreading fast.

Epidemiologists call this strategy of preventing a huge spike in cases “flattening the curve,” and it looks like this:

An infographic that shows the goals of mitigation during an outbreak with two curves. The X-axis represents the number of daily cases and they Y-axis represents the amount of time since the first case. The first curve represents the number of cases when no protective measures during an outbreak are implemented and displays a large peak. The second curve is much lower, representing a much smaller rise in the number of cases if protective measures are implemented.

“Even if you don’t reduce total cases, slowing down the rate of an epidemic can be critical,” wrote Carl Bergstrom, a biologist at the University of Washington in a Twitter thread praising the graphic, which was first created by the CDC, adapted by consultant Drew Harris, and popularized by the Economist. The chart has since gone viral with the help of the hashtag #FlattenTheCurve.

Flattening the curve means that all the social distancing measures now being deployed in places like Italy and South Korea, and on a smaller scale in places like Seattle and Santa Clara County, California, aren’t so much about preventing illness but rather slowing down the rate at which people get sick.

The CDC advises that people over age 60 and people with chronic medical conditions — the two groups considered most vulnerable to severe pneumonia from Covid-19 — to “avoid crowds as much as possible.”

“If more of us do that, we will slow the spread of the disease,” Emily Landon, an infectious disease specialist and hospital epidemiologist at the University of Chicago Medicine, told Vox. “That means my mom and your mom will have a hospital bed if they need it.”

So even if you’re young and healthy, it’s your job to follow social distancing measures to avoid spreading it to others, and keep the epidemic in slow motion. “The more young and healthy people are sick at the same time, the more old people will be sick, and the more pressure there will be on the health care system,” Landon explained.

Hospitals filled with Covid-19 patients won’t just strain to care for those patients — doctors may also have to prioritize them over others. “Right now there’s always a doctor available when you need one, but that may not be the case if we’re not careful,” Landon said.

Staying home helps prevent the US health system from being overloaded

Continue reading “How canceled events and self-quarantines save lives, in one chart”