One more academic achievement for YHLO!

Recently, together with YHLO, the Tokyo Metropolitan Institute of Medical Science(TMIMS), Graduate School of Medicine the University of Tokyo Hospital and other medical institutes jointly published the "Serologic Survey of IgG Against SARS-CoV-2 Among Hospital Visitors Without a History of SARS-CoV- 2 Infection in Tokyo, 2020-2021[1]" won the 2022 Paper of the Year Award from the Japan Epidemiological Association (JEA)[2].

The first author and corresponding author of the paper are Professor Takahiro Sanada and Professor Michinori Kohara from the Tokyo Metropolitan Institute of Medical Science(TMIMS). At the same time, the authors of the paper also include Dr. Fuzhen Xia, Chief Scientist of YHLO, Dr. Chungen Qian, Deputy General Manager of YHLO, and Mr. He Fan, General Manager of Drawray (subsidiary corporation of YHLO).

In this study, 23,234 outpatients who visited 14 hospitals in Tokyo, Japan from 1st September 2020 to 31st March 2021, were randomly selected as research participants. The iFlash 3000 chemiluminescence immunoassay analyzer and the supporting chemiluminescent COVID-19 IgG antibody and IgG-S1 antibody detection kit from YHLO were used to detect the COVID-19 IgG antibody and IgG-S1 antibody on the remaining serum samples of all study participants.

All 23,234 study participants, including 11,553 (49.7%) males and 11,681 (50.3%) females, aged 0 to 103 years (median age 69 years), were undiagnosed with 2019-nCoV infection (COVID-19), and none of them had symptoms related to the Covid-19 at the time of blood collection.

Of the 23,234 study participants, 425 were positive for IgG and/or IgG-S1 (242 were positive for IgG, 329 were positive for IgG-S1, and 146 were positive for both IgG and IgG-S1). The overall serum prevalence of IgG in the population was 1.83% (1.67% and 1.99% for males and females, respectively). After grouping according to age, among participants aged ≤19 years, 20-39 years, 40-59 years, 60-79 years and ≥80 years old, the serum prevalence of IgG was 1.03%, 2.42%, 2.11%, 1.91% and 1.20%. Among participants classified by the hospital location, IgG seroprevalence was 1.98% in special wards and 1.53% in the Tama area (suburbs). Univariate analysis and multivariate logistic regression analysis adjusted by gender and hospital area showed that the serum prevalence of IgG was significantly higher in the special wards of the hospital than in the Tama area, and the serum prevalence of IgG was significantly lower in patients ≥80 years old. (See Table 1 and Table 2 for details).

The study also estimated the number of people who were positive for COVID-19 IgG antibodies among residents in Tokyo by adjusting the serum prevalence of Covid-19 IgG antibodies and the age and sex structure of residents in Tokyo, pointing out that in September, October, November and December 2020, January, February and March 2021, the adjusted IgG seroprevalence rates of residents in Tokyo were 1.15%, 0.91%, 1.62%, 1.83%, 1.82%, 2.96%, and 3.40%, respectively. During the month, the number of COVID-19 IgG antibody positive cases among residents in Tokyo was 158,743, 125,539, 224,769, 253,011, 252,139, 409,659, and 470,778 cases, respectively. According to an estimate of 120,986 cumulative confirmed cases in Tokyo using Covid-19 nucleic acid or antigen detection, the actual number of Covid-19 infections is 3.9 times that of known confirmed cases. (See Figure 1 for details). 

The study pointed out that most asymptomatic patients with Covid-19s have not been tested for Covid-19 nucleic acid or antigen, and the actual number of Covid-19 infection cases in Tokyo may be underestimated. The detection of Covid-19 IgG antibodies will help strengthen the further detailed understanding of the epidemic and spread of Covid-19s. Controlling the COVID-19 pandemic is also crucial.

As a leading IVD company in China, YHLO is committed to the research and development of Covid-19 detection reagents based on mature technology platforms and systematic R & D solutions and has successively launched Covid-19 IgM and IgG antibody detection kits and antigen detection kits, Neutralizing antibody detection kit. As of the end of December 2022, customers in more than 100 countries and regions around the world have used YHLO's products, and more than 380 articles have been published using YHLO's Covid-19 reagents, with an impact factor of more than 1,800 points. YHLO's Covid-19 IgM and IgG antibody detection kits also passed the external quality assessment organized by the Clinical Laboratory Center of the National Health and Medical Commission in 2022 with a full score.

At this stage, with the publishment of documents like "Overall Plan on the Implementation of “Class B and Class B Control” for COVID-19 Infection" [3] and "Diagnosis and Treatment Protocol for COVID-19 Patients (Tentative 10th Edition)" [4] and other documents from the National Health Commission, YHLO's Covid-19 antibody detection kit will continue to help the prevention and control of domestic epidemics, and it is mainly used to judge the immunity and resistance after vaccination/infection, and guide whether the subject should strengthen vaccination; Monitor and evaluate the immunity level of the community population to understand the Covid-19 infection situation of the community population. At the same time, it has a certain value for retrospective diagnosis of Covid-19 infection, monitoring of disease changes, and diagnosis of Covid-19 complications, providing a reference for future optimization of resource allocation and epidemic prevention and control policies.

References

[1]Sanada T, Honda T, Yasui F, et al. Serologic Survey of IgG Against SARS-CoV-2 Among Hospital Visitors Without a History of SARS-CoV-2 Infection in Tokyo, 2020-2021. J Epidemiol. 2022 Feb 5;32(2):105-111. DOI: 10.2188/jea.JE20210324

[2]https://jeaweb.jp/journal/otherContents/awards/paperOfYear/index.html

[3]https://www.nhc.gov.cn/xcs/zhengcwj/202212/e97e4c449d7a475794624b8ea12123c6.shtml

[4]https://www.nhc.gov.cn/xcs/zhengcwj/202301/32de5b2ff9bf4eaa88e75bdf7223a65a.shtml