Withdrawn as Duplicate: Two Human Challenge Studies Confirm High Infectivity of Norwalk Virus

This article has been withdrawn, as it is a duplicate which was erroneously accepted and published by OUP of an article previously published in The Journal of Infectious Diseases. The content available here has been published in its final form at https://doi.org/10.1093/infdis/jiu385. The publisher apologizes for any inconvenience.