Background Austria, and particularly its westernmost federal state Vorarlberg, developed the highest COVID-19 incidence rate worldwide in November 2020. Health care workers (HCW) may be at higher risk of contracting the disease within the working environment and therefore the seroprevalence in this population is of particular interest. Here, we analyzed SARS-CoV-2-specific antibody response in Vorarlberg HCW in a prospective cohort study. Methods A total of 395 HCW have been tested at three different time points for the prevalence of anti-SARS-CoV-2 IgG antibodies specific for NP and RBD. Enrollment started in June 2020 (t1), two months after the end of the first wave. Re-testing took place between October to November at the beginning of the second wave (t2), and again at the end of the second wave in January 2021(t3). Results At t1, 3% of HCW showed a strong IgG-specific responses to either NP or RBD. At t2, the rate increased to 4%, and after the second wave in January 2021, 14% had a strong response, which was assessed to be stable for up to ten months. The amount of HCW with anti-SARS-CoV-2 IgG antibodies was 38% higher than the number of infections found by PCR. Conclusion We found low numbers of SARS-CoV-2-seropositive HCW in a hotspot setting after the first wave but a massive increase during the second wave distinctly surpassing the number of infected HCW identified by PCR. Our findings, therefore, offer support for the routine application of serological testing in management of the ongoing COVID-19 pandemic.

ObjectivesAustria, and particularly its westernmost federal state Vorarlberg, developed an extremely high incidence rate during the COVID-19 pandemic. Healthcare workers (HCWs) worldwide are known to have an increased risk of contracting the disease within the working environment and, therefore, the seroprevalence in this population is of particular interest. We thus aimed to analyse SARS-CoV-2-specific antibody dynamics in Vorarlberg HCWs.DesignProspective cohort study of HCWs including testing at three different time points for the prevalence of anti-SARS-CoV-2 IgG antibodies specific for nucleocapsid protein (NP) and receptor-binding domain (RBD).SettingAll five state hospitals of Vorarlberg.ParticipantsA total of 395 HCWs, enrolled in June 2020 (time point 1 (t1)), 2 months after the end of the first wave, retested between October and November at the beginning of the second wave (time point 2 (t2)) and again at the downturn of the second wave in January 2021 (time point 3 (t3)).Main outcomesWe assessed weak and strong seropositivity and associated factors, including demographic and clinical characteristics, symptoms consistent with COVID-19 infection, infections verified by reverse transcription PCR (RT-PCR) and vaccinations.ResultsAt t1, 3% of HCWs showed strong IgG-specific responses to either NP or RBD. At t2, the rate had increased to 4%, and at t3 to 14%. A strong response was found to be stable for up to 10 months. Overall, only 55% of seropositive specimen had antibodies against both antigens RBD and NP; 29% had only RBD-specific and 16% only NP-specific antibodies. Compared with the number of infections found by RT-PCR, the number of HCWs being seropositive was 38% higher.Conclusion and relevanceSerological testing based on only one antigen implicates the risk of missing infections; thus, the set of antigens should be broadened in the future. The seroprevalence among participating HCWs was comparable to the general population in Austria. Nevertheless, in view of undetected infections, monitoring and surveillance should be reconsidered.

IntroductionThe prevalence of type 2 diabetes mellitus (T2DM) is higher in peripheral artery disease (PAD) than in coronary artery disease (CAD) patients, and PAD overall confers higher cardiovascular risk than CAD. How cardiovascular risk compares between PAD and CAD patients when analyses are stratified by the presence of type 2 diabetes is unclear and is addressed in the present study.Research design and methodsWe prospectively recorded major cardiovascular events (MACE; ie, cardiovascular death, myocardial infarction or stroke) over 10.0±4.7 years in 923 patients with stable CAD, of whom 26.7% had T2DM and in 292 patients with PAD, of whom 42.1% had T2DM. Four groups were analyzed: CAD patients without diabetes (CAD/T2DM−; n=677), CAD patients with T2DM (CAD/T2DM+; n=246), PAD patients without diabetes (PAD/T2DM−; n=169) and PAD patients with T2DM (PAD/T2DM+; n=123).ResultsThe event rate for MACE increased over our four investigated groups: it was lowest in CAD/T2DM− patients (2.52 events per 100 person-years). It was significantly higher in CAD/T2DM+ patients (3.96 events per 100 person-years; p<0.001), in PAD/T2DM− patients (3.68 events per 100 person-years; p=0.022), and in PAD/T2DM+ patients (7.10 events per 100 person-years; p<0.001), who in turn were at a higher risk than CAD/T2DM+ or PAD/T2DM− patients (p=0.001 and p<0.001, respectively). Cox regression analysis after multivariate adjustment showed that the presence of T2DM (HR=1.44 (95% CI 1.09 to 1.92); p=0.012) and the presence of PAD versus CAD (HR=1.48 (95% CI 1.15 to 1.91); p=0.002) were mutually independent predictors of cardiovascular events.ConclusionsIn conclusion, our data show that T2DM as well as the presence of PAD versus CAD are mutually independent predictors of MACE. Patients with both PAD and T2DM are at an exceedingly high risk of cardiovascular events.