However, if such bias existed it was likely to be random and therefore not affect the study results. In addition, we investigate regional and national differences in seroprevalence. Methods: This research involved a bi-national prospective observational cohort study including 3272 adults employed at Falck in Sweden and Denmark. Participants were tested for SARS-CoV-2 antibodies every second week for a period of 8 weeks from 22 June 2020 until 10 August 2020. Descriptive statistics as well as multivariable logistic Rabbit Polyclonal to RPS12 regression analyses were applied. Results: Of the 3272 Falck employees participating in this study, 159 (4.9%) tested positive for SARS-CoV-2 antibodies. The seroprevalence was lower among Danish Falck employees than SPDB among those from Sweden (2.8% in Denmark and 8.3% in Sweden). We also found that the number of customer or patient contacts during a workday was the SPDB most prominent SPDB predictor for seropositivity and that ambulance staff was the most vulnerable staff group. Conclusion: Our study presents geographical variations in seroprevalence within the Falck organization and shows evidence that social interaction is one of the biggest risk factors for becoming infected with SARS-CoV-2. = 8000) and Sweden (= 2000) were asked to participate in the study, and 25.3% of Danish employees agreed, while 62.4% of Swedish employees did. Participants were tested for SARS-CoV-2 antibodies using the same test every second week for a period of 8 weeks from 22 June 2020 to 10 August 2020. 2.1. Assessing Seroprevalence IgG and IgM antibodies against SARS-CoV-2 were measured in whole blood using the Livzon lateral flow test (Livzon Diagnostics, Zhuhai, Guangdong, China), which we validated with a specificity of 99.54% (95% CI: 98.7C99.9) and a sensitivity of 82.58% (95% CI: 75.7C88.2) . The participants did The tests themselves, that they received guidelines on paper and on video. The check needed that the individuals devote one drop of bloodstream and two drops of buffer (isotonic saline) in two distinct cassettes. After 15 min, a conclusive check demonstrated a control range, and if IgM or IgG were detected another check range for every appeared. To ensure full identification of individuals with antibodies, test outcomes of individuals with only 1 antibody (IgG or IgM) recognized were validated utilizing a different make of check. Because of this follow-up check, the anti-SARS-CoV-2 (IgG/IgM) POC-test (lateral movement) WONDFO was utilized. This check was validated inside our laboratory in the Division of Clinical Immunology, Copenhagen College or university Hospital, Denmark. A level of sensitivity was showed because of it of 94.7% (95% CI: 89.8C97.7) and a specificity of 98.7% (95% CI: 97.4C99.4) (unpublished data). The individuals did The WONDFO check themselves just as as the Livzon check. A positive check was classified like a check indicating the current SPDB presence of either IgG, IgM or both antibodies. 2.2. Covariates For the four events that individuals were examined for SARS-CoV-2 antibodies, they answered a short questionnaire also. With this, they reported their work function: ambulance personnel, firefighter, healthcare personnel, office personnel, roadside assistance or field personnel. Participants had been also asked to record their national area of residence through the research period and if they got an antibody check done beyond this research. Moreover, individuals indicated just how many people they had experienced during workdays, normally, for both weeks ahead of tests: 0, 1C5, 6C10, 11C20, and a lot more than 20. 2.3. Figures Statistical analyses had been performed using Business Guidebook 7.1. Descriptive figures were conducted to research the distribution of research individuals, that was presented as percentages and frequencies. National variations in the distribution had been analyzed using = 2080) participated in every four rounds of tests, 86% (= 2800) participated in at least three rounds and 95% (= 3096) participated in at least two rounds. 3.1. Features of the analysis Population There have been national variations in the distribution of features between Danish and Swedish individuals (Desk 1). More males than ladies participated in Denmark (75.5% men), as the opposite was the case among SPDB Swedish participants (32.9% men). In both national countries, about half from the individuals were between your age groups of 40 and 60. A smaller sized percentage of Danish individuals reported a lot more than ten person connections each day (9.7%) in comparison to Swedish individuals (20.3%). Desk 1 Description from the cohorts in Sweden.