Yesterday, a research team led by Hou Fanfan of Southern Medical University, Zhang Kang of Macao University of Science and Technology, Yang Zhenglin of the University of Electronic Science and Technology, and Huang Ailong of Chongqing Medical University published the latest research results on new coronary pneumonia in the prestigious journal Nature Medicine. After analyzing the antibodies of neo-coronavirus in serum in 17,368 people in several regions, they found that the positive rate of serum neo-coronavirus antibody was 2.5% in people with direct contact with the hospital, and 0.8% for people with no direct contact with the hospital.
Specifically to the various groups involved in the study, the serum-positive rate of different groups in Wuhan was between 3.2% and 3.8%, and the serum-positive rate of the population in other areas decreased with the increase of distance with Wuhan.
This week, Wuhan City concentrated nucleic acid testing results came out, a total of 9899828 people of nucleic acid testing, no confirmed cases found, found asymptomatic infection 300, detection rate of about three thousandths.
The above data give us a clear understanding of the current situation in Wuhan. However, nucleic acid testing can only be used to understand the current infection; Because in theory, anyone who has been infected with the new coronavirus will have antibodies against the new coronavirus in the plasma, and these antibodies will exist for a long time. (Click on the hyperlink to learn more about antibody detection)
Therefore, through the serological investigation of neo-coronavirus antibodies, we have the potential to learn the true epidemiological situation of the new coronavirus.
In this study, the researchers first developed an IgM and IgG antibody detection technique for the new coronavirus N protein and S protein, which were validated in different populations to detect 100% and 99.3% specificity of IgM and IgG, respectively.
Then, between March 9 and April 10, 2020, researchers tested 17,368 people in four different regions of China for IgM and IgG antibodies.
Let’s take a look at the data in Wuhan. The serum-positive rate of 714 health care workers was 3.8 per cent, the serum-positive rate of 346 hotel staff (hotels where medical personnel were staying during the outbreak) was 3.8 per cent, and the serum-positive rate of 219 health-care workers’ families was 3.2 per cent.
Take a look at Jingzhou and Honghu around Wuhan. The serum-positive rate of 3,019 health care workers was 1.3%, and the serum-positive rate of 979 patients who went to the hospital for routine maintenance hemodialysis but did not show symptoms of new coronary pneumonia was 3.6%.
In Chongqing, the serum-positive rates of 319 health care workers and 993 outpatients in hospitals were 3.1% and 3.8%, respectively. In Chengdu, the serum-positive rate of 9,442 community residents was 0.58%. In Guangzhou and Foshan, the serum-positive rate of 563 patients who went to the hospital for dialysis was 2.8%, the serum-positive rate of 260 health care workers was 1.2%, and the serum-positive rate of 442 factory workers was 1.4%.
Based on the above data, the researchers believe that the serological test results are consistent with the early spread of the new coronavirus in China.
In addition, from the test results, although IgG has the highest serum-positive rate, it is important to note that some people only IgM or IgG positive. Therefore, the researchers believe that for serological studies, IgM and IgG should be measured at the same time.
The researchers also found that RT-PCR nucleic acid tests for nasal swabs can only detect viral nucleic acidin in a very small number of people’s samples, compared to serum antibody tests. Of the 23 patients tested positive for RT-PCR, 19 were Positive for IgG and 2 were Positive for IgM.
It is also worth noting that the researchers did not find significant differences in serum-positive rates between different sexes (1.6 per cent for men and 1.3 per cent for women), but for those older than 65 years of age, the serum-positive rate was significantly higher (2.0 per cent for those aged 65 and 1.3 per cent for 65-year-olds).
Overall, the above data are critical to our ability to understand the overall prevalence of the new coronary outbreak and the infection capacity of the new coronavirus. However, more research is needed to determine whether these data can be extended to other regions or populations. In addition, since the population involved in this study was not obtained by random sampling, there may be some deviation in serum positive rates. The author of this article . . . BioTalker