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Why Does Disease Spread so Fast?

Authors: Chad Cai, Jiayi Chen, Hill Huang, Charles Zhao, Lambert Zheng, Leon Zhou

Editors: Tiffany Chan, Joyce Hai, Demi Leng, Ethan Liu, Katelyn Ma, Lydia Ren, Shannon Tan, Tyler Vazquez, Molly Zhao

Artists: Tiffany Chen, Jane Liu, Nicole Wang, Nicole Wei


Different Transmission Types

To understand the fast spread of the current novel coronavirus, it is important to first introduce different transmission methods of other diseases. Common transmitting agents include sneezing, coughing, bodily contact, sharing needles, and fecal-to-oral contact. For instance, HIV requires direct sexual contact or shared bodily fluids (blood, seminal and vaginal) for others to be infected. This type of transmission makes HIV relatively difficult to spread in regular day-to-day contact. On the other hand, for COVID-19, respiratory droplets can be transmitted up to a distance of six feet from sneezing or coughing.

Although people tend to believe that the coronavirus cannot thrive without a host, a study from the New England Journal of Medicine found that viruses can still be infectious in the air or on surfaces for various periods, ranging from hours to days. When fluids, such as mucus and respiratory droplets, are left on a surface (doorknobs, pens, or credit cards), the virus can still cause infection. Another way that viruses spread is when people come in close contact with inf