CSF1R and Bell's palsy: Having in mind the concerns that arose by the intranasal use of CTB and its subsequent accumulation in the olfactory bulb of mice [61] and that some vaccines administrated by the intranasal route have been associated with Bell's palsy in humans [62], the fact that CTB-Fim2 administrated by the intraperitoneal route also offers protection, supports its value as a protective immunogen.