This study has shown that there is a need to understand and take into account how people subjectively perceive risks and how that influences their decision-making, in order to understand their choices and behaviours. Theories of risk perception and decision-making can help to explain differences in perceptions of severity and susceptibility of diseases and vaccines. Importantly, this study has found that health messages about the risks of disease which are communicated as though there is equality of risk in the population may be unproductive as these messages are perceived as unbelievable or irrelevant. The findings from this study have implications beyond the issue of childhood vaccinations as we grapple with communicating risks of new epidemics. Using and developing a more complex theoretical approach to public health issues may increase the likelihood we can understand the barriers to action and develop effective methods of communicating risk and delivering acceptable public health interventions. And indeed may usefully contribute to the current debates, especially in the UK, of how these theories of risk and decision-making can be used to 'nudge' other health behaviours [38, 39] . Development and Applications of VSV Vectors Based on Cell Tropism Viral vectors have been available in various fields such as medical and biological research or gene therapy applications. Targeting vectors pseudotyped with distinct viral envelope proteins that influence cell tropism and transfection efficiency are useful tools not only for examining entry mechanisms or cell tropisms but also for vaccine vector development. Vesicular stomatitis virus (VSV) is an excellent candidate for development as a pseudotype vector. A recombinant VSV lacking its own envelope (G) gene has been used to produce a pseudotype or recombinant VSV possessing the envelope proteins of heterologous viruses. These viruses possess a reporter gene instead of a VSV G gene in their genome, and therefore it is easy to evaluate their infectivity in the study of viral entry, including identification of viral receptors. Furthermore, advantage can be taken of a property of the pseudotype VSV, which is competence for single-round infection, in handling many different viruses that are either difficult to amplify in cultured cells or animals or that require specialized containment facilities. Here we describe procedures for producing pseudotype or recombinant VSVs and a few of the more prominent examples from envelope viruses, such as hepatitis C virus, Japanese encephalitis virus, baculovirus, and hemorrhagic fever viruses. Viruses are obligate parasites of living organisms, and their replication is absolutely dependent on the host cell's machinery. The entry of enveloped viruses requires host cell binding and membrane fusion that is mediated by envelope proteins located on the surface of the virion.