Comparisons of the real-world spread of the COV-19 coronavirus with computer models indicate that the travel restrictions imposed by authorities in China and other nations have delayed the progress of the outbreak by a matter of days or weeks.
The models suggest that the best way to mitigate the epidemic isn't through travel restrictions, but through public health interventions and behavioral changes — such as frequent hand-washing and social distancing.
The open-access findings were published today by the journal Science, by a research team including scientists from the U.S., Italy and China. Elizabeth Halloran, a biostatistician who works at Seattle's Fred Hutchinson Cancer Research Center and the University of Washington, is a member of the team.
Researchers took advantage of a computer model known as GLEAM, which traces the dynamics for the global transmission of diseases based on a given set of parameters. The team tweaked those parameters in an effort to determine how COVID-19 might have spread under different conditions.
The results suggest the travel ban that Chinese authorities introduced on Jan. 23 in the city of Wuhan, the epicenter of the epidemic, slowed the virus' spread across China by three to five days.
By early February, airlines had begun restricting international flights to and from China. But computer modeling of the real-world spread of the virus suggests that "a large number" of individuals who were exposed to COVID-19 traveled internationally without being detected. Those individuals seeded fresh outbreaks elsewhere, the researchers said.
"This finding is consistent with the emergence of COVID-19 outbreaks in countries across the world, including Italy, Republic of South Korea and Iran in the second half of February," the team reported.
Contribution to the relative risk of importation of the top 10 Chinese cities (plus the rest of Mainland China) until 22 January and after Wuhan travel ban from 23 January to 1 March 2020. The listed countries correspond to the top 20 countries at risk of importation. Copyright © 2020, American Association for the Advancement of Science
The models suggest restrictions on flights to and from China slowed the virus' spread by two to three weeks.
Researchers cautioned that their findings were based on preliminary parameters relating to the incubation time for the virus, and prior knowledge about earlier coronavirus epidemics. Nevertheless, they said the computer models could help guide expectations for controlling the virus' spread.
"Moving forward we expect that travel restrictions to COVID-19 affected areas will have modest effects, and that transmission-reduction interventions will provide the greatest benefit to mitigate the epidemic," they said.
The study in Science is called "The Effect of Travel Restrictions on the Spread of the 2019 Novel Coronavirus (COVID-19) Outbreak." The University of Florida's Ira Longini and Northeastern's Alessandro Vespignani are corresponding authors. Co-authors include Halloran as well as Jessica Davis, Marco Ajelli, Corrado Gioannini, Maria Litvinova, Stefano Merler, Ana Pastore y Piontti, Kunpeng Mu, Luca Rossi, Kaiyuan Sun, Cecile Viboud, Xinyue Xiong and Hongji Yu.
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Snap’s parental controls.
Courtesy of Watchful.
Snapchat is planning to introduce Family Center, which would allow parents to see who their children are friends with on the app and who they’ve messaged within the last seven days, according to screenshots provided by Watchful, a product intelligence company. Parents would also be able help their kids report abuse or harassment.
The parental controls are still subject to change before finally launching publicly, as the Family Center screenshots—which were first reported by TechCrunch—reflect features that are still under development.
Santa Monica-based Snap and other social media giants have faced mounting criticism for not doing more to protect their younger users—some of whom have been bullied, sold deadly drugs and sexually exploited on their platforms. State attorneys general have urged Snap and Culver City-based TikTok to strengthen their parental controls, with both companies’ apps especially popular among teens.
A Snap spokesperson declined to comment on Friday. Previously, Snap representatives have told dot.LA that the company is developing tools that will provide parents with more insight into how their children are engaging on Snapchat and allow them to report troubling content.
Yet Snap’s approach to parental controls could still give teens some privacy, as parents wouldn’t be able to read the actual content of their kids’ conversations, according to TechCrunch. (The Family Center screenshots seen by dot.LA do not detail whether parents can see those conversations).
In addition, teenage users would first have to accept an invitation from their parents to join the in-app Family Center before those parents can begin monitoring their social media activity, TechCrunch reported.