XK and influenza: Though i.n. infection with VANBT resulted in induction of NA titer (Fig 1G), animals previously infected with VANBT did not show any significant protection against re-infection (Fig 5B), which suggests that infection with EV-D68 fails to provide the degree of immunity induced by infection with other respiratory viruses in this model, i. e., influenza and RSV, where infection induces complete protection to re-infection [62–65].