Periodic epidemics may result in accumulation of a sufficient cohort of susceptibles to sustain transmission of the epidemic serotype. Age and Socioeconomic Status 1. Incidence rates of infection and disease are inversely proportional to age. Rates of infection and disease are also higher among children of lower socioeconomic classes. C. Transmission 1.
Transmission is most efficient in households and families.
V. Laboratory Diagnosis A. Virus Isolation. Cell culture is labor intensive and expensive. Experience with other specimens is more limited.