Epidemiological investigators have been compared to "scouts" in the war against the novel coronavirus. Others refer to them as the "Sherlock Holmes" of the epidemic, reeling silks (helpful information) from the cocoons of the COVID-19 epidemic.

For instance, due to their work, all of 2,098 close contacts and 2,625 secondary contacts with a locally transmitted case of the virus, which was confirmed on Jan. 12, could be quickly identified over the previous 14 days quarantined and put under close medical observation.

Zheng Qingming, a member of the epidemiological investigation team of Luohu and director of the health education and promotion section of theLuohu Center for Disease Prevention and Control, said: "Our team's task is to block the virus before it preys on next person, and cut the transmission chains as soon as possible."

The team comprises more than 380 people who work on different shifts around the clock. Among them, about 180 people are epidemiological investigators sent by neighboring Futian and Dapeng districts, and other units of the Shenzhen city, and even Guangzhou, Jiangmen, and Shaoguan cities.

Zheng said: "Only relying on Luohu's power is not enough to fulfill the tremendous amounts of work related to the epidemiological investigation, prevention and control, sampling and disinfection and sterilization work."

The team is divided into information, investigation, close contacts, and disinfection and sterilization groups. They have clear labor divisions, work closely with each other, and each performs their functions. The main task is to find who infected a particular case, where this case has been over the previous 14 days, and during that time to whom the case might have passed the virus.

The epidemiological group staff obtains information from calls, field investigation, the public security department investigation, and extensive data analysis. After accessing vast amounts of data and clues, they start the complicated data analysis process to screen and master the basic knowledge of the cases. Then, after verifying their whereabouts and close contacts, the investigators quickly form their report.

Then the ball is kicked to the court of the close contact group, who will locate the close contacts and secondary contacts, carry out relevant epidemic prevention and control measures, and advise their neighborhoods what to do to sever the transmission chains.

At the same time, the disinfection and sterilization group and the sampling group will arrive in the affected regions to do their parts of the work.

Thanks to the team's efficiency, it takes about four hours to master the basic information of new infections after they are confirmed, including their vaccination records, and 24 hours to screen, quarantine, and disinfect their whereabouts, close contacts, and secondary contacts. That means most critical epidemic prevention and control measures are expected to be carried out within 24 hours after new cases are confirmed.

"It would be a relief if new confirmed cases were found among close contacts or secondary contacts under quarantine, as that proves that we have done our best to contain the virus and reduce its impact," Zheng said.

As Zhang Wenhong, director of the National Medical Center for Infectious Diseases and director of the Department of Infectious Diseases at Huashan Hospital affiliated to Fudan University, said, "During this period, local epidemic prevention and control forces are 'treading on thin ice, and are always ready for battle.' Once a local infected person appears, the epidemic prevention force will by no means waste the golden opportunity as they have to make full use of every second to identify and locate all close contacts and secondary contacts as soon as possible. The transmissions of the virus can be controlled through meticulous and rapid work. We hope that the virus can be controlled and life and work can be as normal as possible."

Zheng said that's precisely how the team will work after new cases are reported.

The team members work around the clock and have no fixed commute time. As soon as the "alarm" of the epidemic sounds, everyone must devote himself to it, and it is almost difficult to squeeze out time for a drink of water or a word. On days of many confirmed cases, some workers even stayed awake for two days without sleeping.

"We have to catch up with the spread of the virus. We have to stop it before it infects the next person. We want all citizens to have a good Spring Festival," Zheng added.