By Hope Chung, Singing Wang, Ruoyi Song
Coronavirus is known as an airborne disease that affects the respiratory system. The symptoms include coughing, fever, and shortness of breath. In serious cases, the infection can cause severe acute respiratory syndrome, pneumonia, and death. Droplets as the main transmit way of coronavirus, if people come into close contact with the infected person for 1-2 meters, people may inhale the virus. It can also spread through contacts, contacting with the virus-containing secretions, if the virus stays on the hand or skin, it may pass through infection by touching the mouth, nose, or eyes with hands.
As the Coronavirus outbreak (COVID-19) has continued to explore and grow, a total of nearly three million people were diagnosed as confirmed cases worldwide, and more than two hundred thousand people died. Some have called the disease World War iii, whether it is an economic disaster or a threat to the security of all mankind.
As the response to the coronavirus pandemic continues, major cities around the world are locked down.
With the spread of the coronavirus around the world, many countries have chosen to shut down their cities, reducing exposure and blocking transmission through home quarantine. When the coronavirus began to spread from person to person in Wuhan, the government decided to close the city on Jan. 23. After the further outbreak in Italy, Europe became the hardest hit and then spread to the Americas and Africa. The precise number of people diagnosed has become a focus of concern.
Figure 1: Confirmed Cases and Forecast Cases by City
Wuhan was the first city reported COVID 19 confirmed case, it locked down the city on January 23, the eve of the Chinese New Year, announcing that no one can leave Wuhan. Furthermore, on February 2, Wuhan banned the public transportation of buses, subway, and ferries. " I knew that I won't be able to go back to my hometown before the Chinese New Year," said Herry Huang, who has lived in Wuhan for 7 years, while his family lives in Hunan Province, 300 kilometers from Wuhan.
Figure 2: Wuhan, where the first COVID-19 case reported, reopened after 76 days
Before the outbreak, Herry Huang had bought a train ticket to return to Hunan on the eve of Chinese New Year, but as the outbreak spread rapidly, Wuhan locked down the city on Jan. 23, and Huang was trapped in Wuhan the day before he returned home. “Actually, I got opportunities to drive away like many others, but I felt that there would be a risk of spreading the virus, so I chose to stay at home.” Said Huang. He didn't think it would take longer, but he waited in Wuhan alone for three months. He was not allowed to return to Hunan until Wuhan lifted the ban on April 8. "I have stored some food before February 11 when the government started to close all residential buildings with fences, no one is allowed to go out.”
"The community will issue a certificate of entry and exit to every household. During the most severe period, you can't go out. The community staff will buy vegetables and leave them at the door. It's incredible. But we're in a special time, I mean, I've never been in a situation like this. Because of the serious infectious disease, all the shops are closed, people can’t go out, the hospital does not have enough beds. When you are home, the sound that you can only hear is the ambulances, this is horrified and terrible." said Huang.
The city where Huang's family lives, along with Wuhan, is next to Hubei province. Before the closure of the Wuhan city, many Wuhan people drove to Hunan. "We talked to my family members on the phone every day, and I was most worried about my parents because they were both in their 70s and had other complications. My company was supposed to start work in February, but so far we haven't received the mail to return to work. This disease has a huge impact on the economy. But there is nothing we can do. All we can do is face it.”
The effect of human mobility on the Coronavirus epidemic
Countries and cities have been under a stay-at-home order to control the spread of COVID-19, alcohol, and face masks are in short supply. “People in New York didn’t wear masks before. People will glare at the one who wears a mask, my roommate used to wear masks, but she had glared every day, she became afraid to wear one. But now we don't even have dry cleaners, I was afraid to go out and contact people, except to throw the garbage I refused to go out. New York has too many people and people depend on public transportation. It's terrible.” said Karry Kan who is now living in New York City.
COVID 19 has put millions of people out of work and schools, people need to change the way they used to live, commute, and even eat. "I stay at home as much as I can, I use Amazon Fresh, and I walk rather than taking the subway," said Karry Kan.
As the coronavirus pandemic continues, city mobility also has a dramatic decrease. Comparing the data from the Citymapper which integrates the data from walking and cycling to driving through the free mobile app and the desktop website, as the chart below shows, even before New York City, Boston, and Los Angeles started the stay-at-home order, mobility of these cities all reduced by more than 90% a week more after Milan closed the city on March 8.
Figure 3: City Mobility is greatly reduced after the “Stay-at-Home” order announced
To better understand worldwide community mobility and the number of diagnoses, by comparing four regions of the world, including Milan, Los Angeles, Suffolk County, and New York City compared with the dates of issuing the “Stay-at-Home” order in each region. We collected data on coronavirus infection in four regions from January to April 25 and compared the data before and after the lockdown with a chart.
Figure 4: Confirmed cases and growth rate in Milan, LA, NYC, and Boston
Although the growth rates of each city still have a few peaks after stay-at-home orders started, it might be because the longest incubation period of COVID-19 is 14 days. Even if people stop contacting each other face to face, this measure cannot prevent the growth rate immediately decreasing from dramatic growth.
According to the charts, we can observe that the growth rate in these cities has decreased and become flatten, as the days of “Stay-at-Home” Order became longer. Also, the sooner or later the stay-at-home order starts do affect the growth rate of confirmed cases, but in some cities, people have realized that they have to go out less before the order becomes effective, so the growth rate is relatively low.
Looking at the population density and variations by age of the Coronavirus
Due to the elderly having low immunity and other complications, coronavirus, as one of the more infectious respiratory diseases, has a fatal impact on the elderly. Therefore, when analyzing the number of patients in different regions, we calculated the population of these five regions and the proportion of people over 65 years old. To find out whether the number of cases is related to the aging of the population.
Figure 5: Population Density and Amount of Aging
According to the number of population in each city in 2019, we found that Los Angeles and New York City have a large population, and the elderly population in Los Angeles is larger. In the same year, the number of people aged 85 and older in New York City is exploding. Besides, we noticed that Milan, as a highly aging city, has one of the highest mortality rates in the world due to the COVID-19 among these cities. In addition to city mobility, the population density and the amount of aging will become essential factors affecting the number of confirmed cases.
Besides city mobility, population density, and the amount of aging, we also want to include other factors that could affect the confirmed case as well in the future. Smoking is considered as an interference factor now, according to a study from the University of South Carolina, it’s easier for the virus to invade the human body to reproduce for smokers. However, French researchers recently pointed out that nicotine may protect people from COVID-19, and intend to conduct more experiments to study whether nicotine can be used to prevent or treat this deadly disease.
Admittedly, it is challenging to implement the “Stay-at-Home” order; we could not deny its effectiveness. Researchers and experts still have a limited understanding of the spread of the novel coronavirus, but what we can do is to help stop the spread of the COVID-19.
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