22 Acute disseminated encephalitis could not be identified in our data because ICD code precision of 4 digits is required, which was not available; therefore, encephalomyelitis diagnoses (ICD-8 or ICD-9 code 323 and ICD-10 code G04) were exclusion criteria because they include acute disseminated...
Infectious mononucleosis was defined as ICD-10 code B27.9 and ICD-9 code 075. Absolute numbers of cases of IM per age band were converted to rates per 100,000 person-years for each 5-year age band using mid-year population estimates from Office for National Statistics (ONS) as the ...