The seroprevalence of SARS-CoV-2 antibodies among health care workers before the Era of vaccination: A systematic review and meta-analysis

Kayı, İlker; Madran, Bahar; Keske, Şiran; Karanfil, Özge; Arribas, Jose Ramon; Psheniсhnaya, Natalia; Petrosillo, Nicola; Gönen, Mehmet; Ergönül, Önder

BACKGROUND: The prevalence of SARS-CoV-2 infection among HCWs provide information to for the spread of COVID-19 within health care facilities, and to detect the risk groups. OBJECTIVE: We aimed to describe the rate of SARS-CoV-2 seroprevalence and its determinants among health care workers. DATA SOURCES: We used Web of Science, Scopus, MEDLINE, EBSCOhost and Cochrane Library. STUDY ELIGIBILITY CRITERIA: We included the reports of SARS-CoV-2 seroprevalence with a sample size of minimum 1,000 HCWs. METHODS: The study was registered at the International Prospective Register of Systematic Reviews (PROSPERO, no: CRD42021230456). We used PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. The keywords were “COVID-19, “SARS-Co-2”, “Coronavirus”, “seroprevalence”, “health care workers” and “risk factors”. RESULTS: In total 4329 reports were retrieved, the duplications were removed, after filtering according to the title and abstract 25 studies were selected. Risk of bias was assessed in 25 studies; it was low in 13 studies, medium in four studies, and high in eight studies. In meta-analysis by using the random effect model, the weighted average of seroprevalence was calculated as 8% (CI: 6%-10%). The pooled seroprevalence rates of the selected variables that have a rate over the average were male HCWs with 9% (95% CI 7%-11%); HCWs from ethnic minorities with 13% (95% CI: 9% - 17%); high exposure 9% (95% CI: %6 - %13); exposure to the virus outside the health care setting %22 (95% CI: %14 - %32). CONCLUSIONS: Our analysis indicate a SARS-CoV-2 seroprevalence rate of 8% among studies included >1,000 HCWs for the year 2020 before vaccinations started. The most common risk factors associated with higher seroprevalence rate were ethnicity, male gender, and having higher number of household contacts. Working as a frontline HCW was inconsistent in its association with higher seroprevalence.