Although three separate reports have now described the induction of IL-1 in response to VSV challenge in vivo [22, 51, 52] , none of these had examined whether or not the induced IL-1 contributed positively to or was required for generation of immune responses or protection. In other viral infection models where this has been investigated, published reports are not in agreement. For example, Schmitz et al found that IL-1R2/2 mice infected with influenza had a significantly higher rate of mortality than did wild type control animals, but the increase in mortality did not correlate with a higher virus burden in the IL-1R2/2 mice [53] . Three additional reports examined the role of IL-1b, as well as components of the Nlrp3 inflammasome, in control of influenza infection [23, 54, 55] . In these, two out of three found transiently elevated viral loads in mice in which IL-1b production was decreased [23, 54] , the other report found no difference in virus burden [55] . Similarly, only one of the three reports [23] found that a reduction in IL-1b correlated with a reduction in cellular immune responses-the others either did not examine immune responses or did not find a correlation.