What exactly do those two curves show?
Both curves add up the number of new cases over time. The more people reporting with the virus on a given day, the higher the curve; a high curve means the virus is spreading fast. A low curve shows that the virus is spreading slower — fewer people are diagnosed with the disease on any given day. Keeping the curve down — diminishing the rate at which new cases occur — prevents overtaxing the finite resources (represented by the dotted line) available to treat it.
Think of the health care system capacity as a subway car that can only hold so many people at once. During rush hour, that capacity is not enough to handle the demand, so people must wait on the platform for their turn to ride. Staggering work hours diminishes the rush hour and increases the likelihood that you will get on the train and maybe even get a seat. Avoiding a surge of coronavirus cases can ensure that anyone who needs care will find it at the hospital.
What sorts of mitigation measures help transform the red curve into the blue curve?
Diseases spread when one person gives it to one or more others, who go on to give it to more people, and so on. How fast this occurs depends on many factors, including how contagious the disease is, how many people are vulnerable and how quickly they get sick.
The difference between seasonal flu and coronavirus is that many people have full or partial immunity to the flu virus because they have had it before or were vaccinated against it. Far more people are vulnerable to coronavirus, so it has many more targets of opportunity to spread. Keeping people apart in time and space with social distancing measures, self-isolation and actual quarantine decreases opportunities for transmission.
To take the subway example again, a packed car — or a packed subway platform — is a great place to spread the virus. But reducing the number of people on the train or platform, by asking people to work from home or to stagger their working hours, enables individuals to stay farther apart, limiting the spread of the virus. That is social distancing in action.
Mitigation efforts keep people farther apart, making every transmission opportunity marginally less likely. This slows the spread. We should, and will, take the most vulnerable people out of the population altogether by keeping them totally separate. This is what Washington State is trying to do by limiting visitors to nursing homes. Think of this as a reverse quarantine.
What are you doing day-to-day in response to these unusual times?
Like most everyone else, I’m more aware of my surroundings and behaviors. I try to use a sleeve or elbow to open doors, and I wash my hands or use hand sanitizers after I touch a surface that might be contaminated. And I made sure to have a good supply of my prescription and nonprescription medications, just in case any shortages occur after the shutdown of Chinese pharmaceutical suppliers. I’m following the lead of my public health officials here in Philadelphia, where there is only one case as of Tuesday, and travel isn’t restricted. I’m avoiding crowds and sick people. I am going out, and will continue to do so unless a quarantine is ordered or public places are closed.