Interestingly, those with fewer or no herpes labialis outbreaks also mounted a larger immune response to Candida extract, even though it is unrelated to herpes—with greater PBMC proliferation to Candida extract and greater expression of upregulated immune genes in Candida extract, including IFNG, and lower expression of down‐regulated immune genes in Candida extract. Here, IFNG is linked to herpes labialis.