Measles - 7 letters - 7 days after rash onset; Mumps=parotitis - 9 letters - 9 days after onset; RuBELLA-5 days after you start not looking "bella" - bella = 5 letters; Pertussis: "Per(t) Us, Sis" you have to stay in isolation for 5 days after therapy (ussis - 5 letters)
Measles - 7 letters - 7 days after rash onset; Mumps=parotitis - 9 letters - 9 days after onset; RuBELLA-5 days after you start not looking "bella" - bella = 5 letters; Pertussis: "Per(t) Us, Sis" you have to stay in isolation for 5 days after therapy (ussis - 5 letters)
For post Measles is 5-21 and Rubella is 7-21 so the first day of exclusion from post exposure is opposite the rash number.