However, to resolve this constraint, we conducted a random-effects model and subgroup analysis. through PubMed, ScienceDirect, and Google Scholar databases, eligible studies published from January 1, 2020 to January 15, 2021 were included for the systematic review and meta-analysis. The random-effects model was used to estimate the pooled proportion of IgG seropositive HCWs. Publication bias was assessed by funnel plot and confirmed by Egger’s test. Heterogeneity was quantified using I2 statistics. We performed sensitivity analyses based on sample size, diagnostic method and publication status. The study protocol was registered with PROSPERO (CRD42020219086). Findings A total of 53 peer-reviewed articles were selected, including 173,353 HCWs (32.7% male) from the United States, ten European, and three East Asian countries. The overall seropositive prevalence rate of IgG antibodies was 8.6% in these regions (95% CI= 7.2C9.9%). Pooled seroprevalence of IgG antibodies was higher in studies conducted in the USA (12.4%, 95% CI= 7.8C17%) than in Europe (7.7%, 95% CI=6.3C9.2%) and East Asia (4.8%, 95% CI=2.9C6.7%). The subgroup study also estimated that male HCWs had 9.4% (95% CI= 7.2C11.6%) IgG seroconversion, and female HCWs had 7.8% (95% CI=5.9C9.7%). The study exhibits a high prevalence of IgG antibodies among HCWs under 40 years in the USA, conversely, it was high in older HCWs (40 years of age) in Europe and East Asia. In the OSS-128167 months February-April 2020, the estimated pooled seroprevalence was 5.7% (4.0C7.4%) that increased to 82% (6.2C10%) in April-May and further to 9.9% (6.9C12.9%) in the May-September time-period. Interpretation In the view of all evidence to date, a significant variation in the prevalence of SARS-CoV-2 antibodies in HCWs is observed in regions of Europe, the United States, and East Asia. The patterns of IgG antibodies by time, age, and gender suggest noticeable regional differences in transmission of the virus. Based on the insights driven from the analysis, priority is required for effective vaccination for older HCWs from Europe and East Asia. A considerable high seroprevalence of IgG among HCWs from the USA suggests a high rate of past infection that indicates the need to take adequate measures to prevent hospital spread. Moreover, the seroprevalence trend was not substantially changed after May 2020, suggesting a slow progression of long-term SARS-CoV-2 immunity. Routine testing of HCWs for SARS-CoV-2 should be considered even after the rollout of vaccination to identify the areas of increased transmission. Funding None Keywords: Covid-19, Healthcare workers, Seroprevalence, SARS-CoV-2, IgG antibodies Abbreviations: IGG, immunoglobulin-g; IGM, immunoglobulin-m; CMI, chemiluminescent microparticle immunoassay; ELISA, Enzyme-Linked Immunosorbent Assay; P, Proportion/Prevalence; CI, Confidence Interval Research in context Evidence OSS-128167 before this study We searched in PubMed, ScienceDirect, and Google Scholar for peer-reviewed papers and research reports on seroprevalence of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG antibodies, using the search words ‘seroprevalence’, ‘anti-SARS-CoV-2 IgG’ and ‘COVID antibodies’ and OSS-128167 similar terms up to January 15, 2021. We identified 53 peer-reviewed sero-surveys. In this context, to assess the seroprevalence of anti-SARS-CoV-2 IgG antibodies among health care workers (HCWs), peer-reviewed studies published in high-indexed journals have been considered to reduce heterogeneity. Added value of this study This research used existing studies to analyze the pooled-prevalence of anti-SARS-CoV-2 IgG antibodies in HCWs employed in Europe, East Asia, and the United States, and the estimates varied across these geographic regions. Moreover, the seroprevalence of IgG was compared across age groups, gender, OSS-128167 country-wise infection risk, work-place infection risk, and study period. Our research also uses statistical techniques to estimate the pooled seroprevalence of IgG antibodies in the HCWs while capturing heterogeneity in the estimates. In order to understand the global pattern of natural immunity against this obdurate virus, the study allowed us to visualize the progression of seropositive status of IgG antibodies among HCWs prior to vaccination. Implications of all the available evidence Our findings highlight that the immunological landscape has not been changed significantly over time, suggesting a slow progression of long-term SARS-CoV-2 immunity. The seroprevalence of SARS-CoV-2 IgG antibodies among HCWs from the USA is higher than in the countries from Europe or East Asia. As the world plans to find a new equilibrium between minimizing the direct Mouse monoclonal antibody to Keratin 7. The protein encoded by this gene is a member of the keratin gene family. The type IIcytokeratins consist of basic or neutral proteins which are arranged in pairs of heterotypic keratinchains coexpressed during differentiation of simple and stratified epithelial tissues. This type IIcytokeratin is specifically expressed in the simple epithelia lining the cavities of the internalorgans and in the gland ducts and blood vessels. The genes encoding the type II cytokeratinsare clustered in a region of chromosome 12q12-q13. Alternative splicing may result in severaltranscript variants; however, not all variants have been fully described impacts of COVID-19 on the infected and indirect impacts on society, such serological study is crucial to providing new insights into disease transmission. Alt-text: Unlabelled box 1.?Introduction The ongoing pandemic of the 2019 novel coronavirus, known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first reported in late December 2019 in Wuhan, China [1]. It grew into a full-scale pandemic within weeks and is.