It is in this universe. A simple Google search on "herpes New York City". Revealed the following link:
This is the NYC Department of Health and it states "The Health Department reported today that more than a fourth of adult New Yorkers are infected with Herpes Simplex Virus-2, the virus that causes genital herpes."
I don't know what math you were taught but in this universe "a fourth" is 1/4 which is 1 in 4.