Northern Star DeKALB – All NIU students, employees and guests, regardless of vaccination status, are now required to wear masks while indoors on campus, according to a July 28 email sent to students. The change comes as the Centers for Disease Control and Prevention announced Tuesday that now even fully vaccinated Americans should wear masks indoors in areas of high COVID-19 transmission. The new guidance was in part prompted by data showing that the highly transmissible delta variant could possibly be spread by vaccinated people, according to the CDC. DeKalb County has been designated by the CDC as a location with “substantial” levels of COVID-19 transmission.