A meta-analysis of serum prevalence predicts 634 million people already infected with SARS-CoV-2 worldwide

A recent systematic review and meta-analysis conducted by a team of international scientists found that the serum prevalence of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody in the general population was low. I have made it clear.

According to the results of the study, estimating serum prevalence may be a better approach to complement the SARS-CoV-2 infection test and to confirm a more accurate picture of the global burden of pandemics. Research is currently medRxiv* Preprint server.

Since its emergence in December 2019, highly infectious SARS-CoV-2, the causative agent of coronavirus disease 2019 (COVID-19), has infected more than 56.5 million people and more than 1.35 million people worldwide. I’m taking my life. Several measures have been taken to improve the quality and quantity of tests, but due to the limited availability and accessibility of tests in socio-economically disadvantaged countries, SARS-CoV- 2 The exact global prevalence of infection appears to be higher than the reported prevalence. In addition, the increased prevalence of asymptomatic cases may be another important reason for such an underestimated incidence of COVID-19.

The diagnosis of COVID-19 is most commonly made by a rapid antigen test using a nasopharyngeal swab or saliva sample or a polymerase chain reaction (PCR) -based viral RNA test. In contrast, antibody assays are commonly performed to determine the presence of anti-SARS-CoV-2 antibodies in blood samples. A positive antibody test indicates a past SARS-CoV-2 infection in unvaccinated people. Therefore, serological antibody testing provides a more accurate estimate of previous infections in the general population.

Much research has been done nationwide and regionally to estimate the serum prevalence of SARS-CoV-2 antibodies in the general population. These seroepidemiological studies are especially important for identifying high-risk groups. Population-based sero-epidemiological data can be used as a reference for optimal strategic planning of public health measures and COVID-19 vaccine distribution.

Current research design

Scientists have systematically reviewed and analyzed the results of many sero-epidemiological studies to more accurately estimate the global prevalence of SARS-CoV-2 infection. Their search included peer-reviewed articles, preprinted articles, and other non-profit / non-academic articles published between January 1st and August 28th, 2020. A variety of statistical analysis techniques were used to identify demographic differences in serum prevalence and study-level factors. It is associated with serum prevalence. To more accurately estimate global serum prevalence, they revised the available research results on the sensitivity and specificity of the test.

Important findings

A total of 338 serum epidemiological studies were analyzed. 2.3 million people from 50 countries participated in these studies. Approximately 54% and 46% of the studies were conducted in the general and special populations (specific occupation, health status, COVID-19 exposure status), respectively.

Current research analysis reveals that the serum prevalence of SARS-CoV-2 antibody is as low as 3.2% in the general population. Similarly, the serum prevalence of the at-risk population (special population) was 5.4%. For front-line workers, the presence of anti-SARS-CoV-2 antibodies was detected in 6.3% and 10% of healthcare workers and mandatory non-healthcare workers, respectively. Healthcare workers were 1.7 times more likely to be seropositive than the general population. Similarly, people with established contact exposure were also more likely to develop anti-SARS-CoV-2 antibodies.

Relatively low serum prevalence was observed in high-income countries (3.4%). However, differences in estimated serum prevalence were observed in low- and middle-income WHO Global Burden of Disease Study (GBD) regions, from 1.0% in Southeast Asia, East Asia, and Oceania to 18.8% in South Asia. Despite the high risk of SARS-CoV-2 infection and the poor prognosis of COVID-19, a small number of studies were conducted in low- and middle-income countries (25%).

In terms of demographic characteristics, higher serum prevalence is observed in people aged 18-64 years compared to those aged 65 years and older. Whites were less likely to have anti-SARS-CoV-2 antibodies than blacks and Asians.

Most importantly, scientists have observed that estimates of serum prevalence are 14.5 times higher than the corresponding population prevalence in COVID-19 cases. This difference became even more pronounced when the analysis included a study of local serum prevalence. The relatively high frequency of local studies conducted at the COVID-19 hotspot may be the reason for this discrepancy.

Serum prevalence relative to cumulative case incidence using cumulative incidence 9 days before the end of the serum survey.

Overall, these findings indicate that estimating only confirmed COVID-19 cases is not sufficient to determine the actual burden of SARS-CoV-2 infection. By analyzing serum prevalence relative to collective COVID-19 incidence, scientists show that approximately 634 million people may already be infected with SARS-CoV-2 worldwide. I am.