China Focus: Why Beijing needs large-scale nucleic acid testing

Source: Xinhua| 2020-07-13 20:51:36|Editor: huaxia

Construction workers line up at a temporary sampling site in Daxing District of Beijing, capital of China, July 2, 2020. (Xinhua/Cai Yang)

BEIJING, July 13 (Xinhua) -- Beijing has reported no new confirmed domestically transmitted cases of COVID-19 for seven consecutive days.

How to deal with new sporadic cases has become a challenge across the country. Is large-scale nucleic acid testing really necessary? Does every person in the city need to be tested?

Leading experts said in a recent webinar that widespread testing played a significant role in targeted and precise prevention and control of coronavirus in Beijing, setting a good example.

Zhang Wenhong, head of the Center for Infectious Diseases with the Shanghai-based Huashan Hospital of the Fudan University, said that nucleic acid testing is currently the only way to diagnose COVID-19.

Shi Jun, a researcher from healthcare company Novartis, said that it is important to carry out widespread testing as soon as possible; not necessarily universal, but to identify as many people infected as possible.

Calculations show that if a population has less than 10 percent prevalence of COVID-19, pooled testing can be cost-effective, according to Shi. The purpose of testing at this time is to find as many infected people as possible, especially those who may be spreading the virus without showing symptoms, and isolate them before transmission worsens.

According to local health officials, Beijing can test over 1 million people per day if every five swab samples are put into one test.

Zhang said pooled testing may increase the percentage of false-negatives. But for cities like Beijing and Wuhan, a false-negative is not an issue, and getting 80 to 90 percent of people tested means a lot more.

The experts also noted that any test must be combined with effective isolation to control the spread of the disease. No matter what virus detection strategy is used, if isolation is not in place, no detection strategy can succeed.

Yan Ning, a professor at Princeton University and a U.S. National Academy of Sciences foreign associate, said that the virus is not likely to vanish soon, and a possible scenario for COVID-19 in the future could be "close to zero cases."

Zhang said that before the vaccine can be used and the pandemic is over, the strategy China takes will be trying to make COVID-19 a controllable disease.

The best scenario will be no outbreak or large numbers of clustered cases, and prompt and targeted measures against sporadic cases, he added.