Positive Schick test indicates that the person is:
Positive Schick reaction: 
This is characterized by a local inflammatory reaction that reaches maximum intensity in 4–7 days in the test arm and then reduces gradually. This indicates the absence of an immunity to C.diphtheriae.
Parija SC. Textbook of Microbiology & Immunology. Elsevier Health Sciences; 2014. Page:219
Immune to diphtheria
Hypersensitive to diphtheria
Susceptible to diphtheria
Susceptible and hypersensitive to diphtheria