Besides the big bailout programs passed by Congress and the coordination of vaccine development by the National Institutes of Health, most of the hands on work of fighting COVID 19 is happening at the state and local levels. This includes the procurement of medical supplies (ventilators. Personal Protective Equipment, ICU beds, and testing kits), the management of hospital capacity and testing strategies, and coordinating public information distribution. Another important responsibility of state and local leaders is to provide guidelines and limitations for how we need to change individual behviors to help curtail the spread of the disease.
Without viable treatments beyond ventilators and without a vaccine yet available, there is little left that can stop the virus from rampaging around the world claiming thousands of lives. The only remaining preventative measure we have is social distancing. By limiting human to human contact and proximity, the spread of the virus can be slowed. There is no way to stop it completely, since we need to obtain food and care for our sick. By staying apart as much as possible we can at least lessen the stress on the health care system and gain valuable time in which to develop medical interventions.
An example of how our social practices have aided in the fight against the Coronavirus, I combined two state's graphs of deaths over time with the incidence of government restrictions on social interaction. The figure below compares Massachusetts responses to that of Illinois. These two states have similar population characteristics that allow us to compare the effects of other variables. Both have one very large metropolitan area (Boston - 7 m pop; Chicago - 9.5 m pop) which represents over 70% of the population in the entire state (Wikipedia; US Census). Both of the states also have a significant regional and national impact based on their industries and trade (Wikipedia)
I added markers to the graphs of deaths per 100k per day (NPR): a star for the first case identified in each state and a triangle for the date on which major social behavior recommendations were issued. In both of the states, the first case was reported well over a month before significant deaths began to occur.The implementing of social regulations, while similar, differs by 3 to 4 days; Massachusetts lagging behind Illinois..
Both Massachusetts and Illinois took steps to begin limiting social interaction on the 11th and 13th of March. In the case of Illinois (Executive orders), this included limiting large gatherings of people and school closures. In Massachusetts (Executive orders), only nursing home restrictions were invoked. School closures happened 6 days after the first order. On March 20, Illinois instituted "Stay at home" regulations; Massachusetts began stay at home policy on March 24, four days later. When you look at the lines representing deaths per 100K per day, it is clear that both states enacted restrictions over a week before deaths began to rise, The projected outcomes for the two states, however, show strikingly different levels of total deaths: Illinois - 2,269; Massachusetts - 3,326.
Researchers have pointed out relationships between delayed shutdowns and deaths when comparing California and New York (NPR). As mentioned before, there are many factors influencing the virus' behavior. One that may also contribute to the differences in death rate between the two states just mentioned is population density; New York City is more dense that L.A. and Boston is 30% more dense than Chicago (US Census). Staying away from each other seems to be a useful strategy in limiting the spread of the disease until approved treatments and/or vaccines become available. The question is, how do you stay away from people in tight living spaces and packed subways.