Understanding Immune Responses to Viruses-Do Underlying Th1/Th2 Cell Biases Predict Outcome?

Emerging and re-emerging viral diseases have increased in number and geographical extent during the last decades. Examples include the current COVID-19 pandemic and the recent epidemics of the Chikungunya, Ebola, and Zika viruses. Immune responses to viruses have been well-characterised within the innate and adaptive immunity pathways with the outcome following viral infection predominantly attributed to properties of the virus and circumstances of the infection. Perhaps the belief that the immune system is often considered as a reactive component of host defence, springing into action when a threat is detected, has contributed to a poorer understanding of the inherent differences in an individual's immune system in the absence of any pathology. In this review, we focus on how these host factors (age, ethnicity, underlying pathologies) may skew the T helper cell response, thereby influencing the outcome following viral infection but also whether we can use these inherent biases to predict patients at risk of a deviant response and apply strategies to avoid or overcome them.

Contagious margin calls: How COVID-19 threatened global stock market liquidity

The outbreak of the COVID-19 pandemic caused some of the largest — and fastest — market dislocations in modern history. During the outbreak, liquidity quickly evaporated in a coordinated fashion across global markets. We show that a sudden increase in margin requirements during the pandemic is correlated with the withdrawal of global liquidity providers. These effects are concentrated in securities most exposed to high-frequency market makers, consistent with the binding nature of increased capital constraints.