During a pandemic, the most effective tool to break the chain is to test the population at once and isolate the infected and close contacts immediately to stop further spread of virus.

Mass testing rounds are decided according to the special transmission characteristics of omicron variant. The dates and rounds are carefully calculated with scientific and epidemiological trends with estimated gaps (incubation period) in case of any clusters.

Research shows that the infection and reproduction rate of Omicron variant is 70 times faster than that of Delta variant and Corona Virus original strain. Omicron strain can spread rapidly in a short time. Many infected people have to go through multiple tests to detect positive, and multiple rounds of nucleic acid testing are really necessary. Multiple sampling also improves accuracy. If it is detected during the inhibition period, the virus load is small and may not be detected. Therefore, for Omicron strain, one test is far from enough. The transmission period of Omicron strain is mostly 1.5-5 days after infection, and the average generation spacing between infected cases is 3 days. It can be detected effectively only by dynamic repeated detection in a short time. After vaccination for a period of time, even if the virus is infected, the antibody produced by the human body will neutralize and eliminate the virus, resulting in a reduction in the detection rate of the virus, which requires multiple tests.

The Omicron variant has the characteristics of concealment, fast spread and strong transmission. The city with less than 3 million population should complete the sampling within 6 hours. It is determined by the State Council to improve the quality and efficiency of the mass testing.

(OEC)