I kliniske afprøvninger forekom herpesinfektioner (Varicella- Zoster virus, Herpes- simplex virus) en anelse hyppigere hos patienter behandlet med natalizumab end hos placebo- behandlede patienter.
In clinical trials, herpes infections (Varicella-Zoster virus, Herpes-simplex virus) occurred slightly more frequently in natalizumab-treated patients than in placebo-treated patients.