CNN News:接触者追踪对抗击新冠肺炎至关重要

It's possible that those who've had the disease and then recovered from it can be protected from getting infected again by the antibodies they develop. But health officials say there's no proof that will happen. They don't know how long it will last if it does and there are concerns about the dependability of the antibody tests themselves. But they're a step toward knowing who's had COVID-19 and possibly preventing the future spread of it and contact tracing can help with that too.
cnn CHIEF MEDICAL CORRESPONDENT DR. SANJAY GUPTA: Contact tracing is part detective work, part widely used public health method and experts believe a key strategy in fighting the coronavirus pandemic. It relies on identifying and interviewing every person who tests positive, isolating them and then finding anyone else that person could have infected. These people may then be quarantined before they can spread the infection to others. A recent study estimates that because one person infected with COVID-19 can infect two to three other people just one positive case can turn into more than 59,000 cases after 10 rounds of infection.

Contact tracing can help prevent this potential wave of infections from becoming a tsunami. It's a tedious approach but one that is widely credited with stopping SARS in 2004, after that outbreak infected more than 8,000 people all around the world and killed nearly 800. Public health officials say contact tracing is a necessary step before certain businesses can reopen and people can start to return to normal activities.
Some countries including South Korea, India and Singapore are using smartphone technology alongside traditional techniques to ramp up their contact tracing programs. While the CDC in the U.S. has started a pilot program to ramp up contact tracing in some states, many studies estimate that the U.S. will need hundreds of thousands of additional public health workers before a contact tracing system can really begin nationwide.