It is easy to isolate those who have obvious coronavirus symptoms. However, as countries all over the world try to go back to life as it had been before the virus began to spread, the challenge today is to find the best way to prevent those who do not have symptoms, usually oblivious that they have it, from spreading the disease.
These cases pose the gravest danger when they use public transportation operation at pre-pandemic capacity, a threat which a British study conducted in collaboration with Chinese researchers warned of by assessing the danger of the virus spreading among the passengers of high-speed trains.
The study was conducted by the University of Southampton in collaboration with the Chinese Academy of Sciences, China Academy of Electronics and Information Technology, and the Chinese Centre for Disease Control and Prevention. It included 2,334 Chinese index patients who had used the high-speed trains between 19 December 2019 and 6 March 2020 and 72,093 of their close contacts who traveled on trains at the same time for between 0 to 8 hours, studying infection rates based on where they were sitting with respect to the index patient and the co-travel period.
Those sitting directly next to an index patient suffered the highest level of transmission, 3.5 percent contracting the disease on average, while 1.5 percent of those sitting in the same row caught the disease. It also found that the chances of contagion increased by 0.15 percent for every hour that a person seated in the same row traveled with an index patient. While it increases by 1.3 percent per hour for those sitting directly next to the patient.
The lead researcher of the study, Dr. Shengjie Lai, says, "Our study shows that although there is an increased risk of COVID-19 transmission on trains, a person's seat location and travel time in relation to an infectious person can make a big difference as to whether it is passed on”.
While Professor Andy Tatem, who also worked on the study, adds, “Our research is the first to quantify the individual risk of COVID-19 transmission on public transport based on data from epidemiological investigations of disease cases and their close contacts on high-speed trains… It shows that the transmission risk not only relates to the distance from an infected person, but also the time in their presence. We hope it can help to inform authorities globally about measures needed to guard against the virus and in-turn help to reduce its spread.”