Social distancing and the spread of Corona Virus
https://www.nature.com/articles/d41586-020-00741-x
In mid-January, Chinese authorities introduced unprecedented strict measures to contain the virus, stopping movement in and out of Wuhan, the center of the epidemic, and 15 other cities in Hubei province that is home to more than 60 million people. Flights and trains were suspended, and roads were blocked in the Hubei Providence. In short, no one in the Hubei providence can come out. There are being isolated from the rest of the country. Soon after, people in many Chinese cities were told to stay at home and only leave their places to get food or medical help with full protection. Some 760 million people, roughly half the country’s population, were confined to their homes. All these confinement measures took place during the Chinese New Year, which is usually the period with the largest human traffic as it is considered the most important festival in China.
Researchers were eager and interested to know whether these measures were indeed effective in stopping the spread of the virus, and the answer seems to be a definite Yes. Before the interventions, scientists estimated that each infected person passed on the coronavirus to more than two others, giving it the potential to spread rapidly. Early models of the disease’s spread that did not factor in containment efforts suggested the virus would infect 500 million people in China. But between 16 and 30 January, a period that included the first 7 days of the lockdown, Adam Kucharski, a well-known researcher who models infectious-disease spread at the London School of Hygiene and Tropical Medicine, estimates the number of people each infected individual gave the virus to dropped to 1.05. From his research model and the number of reported cases in the following months, it seemed clear that the measures implemented during this time did work.
This article immediately reminds me of our discussion of the spread of an epidemic in a network. In the videos, it talks about in branching process model, which is similar to the spread of the virus in the city where people don’t usually form a closed-looped relationship, the basic reproductive number Ro=pk, in which p=the probability of each infected node passes contagion to neighbors in next wave and k=numbers of neighbors each node has in the next wave. If Ro <1, the n disease dies out in a definite number of steps. Otherwise, then the disease persists indefinitely with a probability >0. What China did is essentially limit the number of k by manually discouraging large gathering and keeping people stay in quarantines. The result shows that the theory actually works in a real-life setting: keeping k indeed helps to die out most of the disease that stops the spread of disease
The concept is also interesting to me because it applies to a smaller network such as our Cornell Community. Before the fall semester start, the administration made strict rules about social distancing, including no events more than 20 people, no fraternity party, always keep 6 feet apart from each other in the public space. It was these confinements, along with other sanitary measures, that made Cornell so successful in terms of keeping all its students safe in school. In conclusion, regardless of the size of the network, social distancing is proven to be effective to stop the epidemic spread. Maybe President Joe Biden should consider enforcing some of these measures to curl up the pandemic in the States.