Suchergebnisse

Though COVID-19 vaccines have shown high efficacy, real-world effectiveness at the population level remains unclear. Based on the longitudinal data on vaccination coverage and daily infection cases from fifty states in the United States from March to May 2021, causal analyses were conducted using structural nested mean models to estimate the population-level effectiveness of the COVID-19 vaccination program against infection with the original strain. We found that in the US, every 1% increase of vaccination coverage rate reduced the weekly growth rate of COVID-19 confirmed cases by 1.02% (95% CI: 0.26%, 1.69%), and the estimated population-level effectiveness of the COVID-19 program was 63.9% (95% CI: 18.0%, 87.5%). In comparison to a no-vaccination scenario, the COVID-19 vaccination campaign averted 8.05 million infections through the study period. Scenario analyses show that a vaccination program with doubled vaccination speed or with more rapid vaccination speed at the early stages of the campaign would avert more infections and increase vaccine effectiveness. The COVID-19 vaccination program demonstrated a high population-level effectiveness and significantly reduced the disease burden in the US. Accelerating vaccine rollout, especially at an early stage of the campaign, is crucial for reducing COVID-19 infections.

By integrating social network theory and leader-member exchange (LMX) theory, we explore the effects of three types of social relationships on employee innovative behavior: weak ties outside the group, LMX, and strong ties within the group. The results from a sample in a high-tech firm showed that LMX fully mediated the positive relationship between out-group weak ties and innovative behavior. Furthermore, within-group strong ties negatively moderated the second stage of this indirect relationship, such that LMX was positively and significantly related to innovative behavior only when the number of within-group strong ties was low. The theoretical and practical implications of these findings are discussed. Copyright (c) 2015 John Wiley & Sons, Ltd.