teritis may be slightly higher than that used in the above calculation (i.e., 6 percent vs. 5 percent).
The method used in this study to compare morbidity and mortality resulting from various diseases is described and illustrated in Chapter 4. Total disease burden values (TDBVs) for rotavirus are calculated using estimates from Table O.5 and infant mortality equivalence values based on a median of committee member perspectives or on an age-neutral perspective. TDBVs thus obtained are 281 (committee median perspective) and 227 (age-neutral perspective).
The principal target for a rotavirus vaccine is the young infant in the first few months of life. Vaccination at this stage could reduce the morbidity associated with rotavirus infection in the early years. A secondary target might be women of childbearing age. This would induce protection during the nursing period by stimulating higher titers of antibody in breast milk. The advantages of this approach to passive protection are reduced by the generally mild or asymptomatic nature of neonatal infection and by the small protection it offers against future symptomatic infection.
Rotavirus appears to be ideally suited to vaccine control. There are a limited number of serotypes involved in human disease. Heterotypic responses occur during natural infection and would simplify the task of type representation in a vaccine. The immune response to natural infection occurs early in life, including the neonatal period, and significantly reduces the morbidity associated with later infection. This protection may be lifelong. The vaccine undoubtedly would be given orally, thus facilitating administration, although it might be found necessary to boost the immune response with parenteral vaccine. The target population is readily identified and vaccination could be combined with the current DPT and MMR programs in the United States, or with the World Health Organization Expanded Program on Immunization schemes for developing countries.
Defining the target population is the first step in calculating the benefit that could be produced by a vaccine candidate. This knowledge