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Appendix E
Questionnaire for Assessing Morbidity-Mortality Trade-Offs

The objective of any vaccine development program is to reduce the medical, social, and financial costs resulting from a disease. Unfortunately, time and resource constraints limit the number of vaccine development programs that can be pursued at one time. Priorities must be set in a manner that is consistent with both the needs of the population and the capabilities of current technologies.

The committee has proposed a method that would allow quantitative comparison of the consequences of various diseases. The system combines information on disease-related illnesses (including incidence, severity, complications, durations, and distributions) and deaths into a single numerical score for each disease. It also allows expression of individual value judgments on the undesirability of different types of illness (morbidity). These value judgments are an inevitable part of the ranking process, whether they are clearly stated or assumed: the committee chose to make them explicit.

The first step in the comparison process was to develop a format that would ensure uniform collection of data on the various diseases. The format consists of categories in which to group estimates of the number of cases, complications, and deaths associated with each disease. Three levels of severity were established for both acute and chronic illnesses, and provision was made for recording the durations of acute illnesses. The format was also designed to show the distribution of cases, complications, and deaths among four age groups.

Attachment 1 lists eight categories of clinical consequences that may be associated with the diseases and vaccines under consideration. We are compiling estimates for each disease of the annual number of days of morbidity in categories A through C, and the annual number of cases in categories D through H. Determination of the total health impact of each disease requires, however, that these figures be modified to reflect the relative importance of morbidity and mortality at different ages.

We are requesting that you prepare a personal, subjective assessment of the relative importance to be assigned to each of the eight categories. Because the relative value may depend on the ages of the afflicted populations, we ask that you provide separate scores for each of four age groups: (1) children under 5 years of age; (2) children



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New Vaccine Development: Establishing Priorities, Volume II, Diseases of Importance in Developing Countries Appendix E Questionnaire for Assessing Morbidity-Mortality Trade-Offs The objective of any vaccine development program is to reduce the medical, social, and financial costs resulting from a disease. Unfortunately, time and resource constraints limit the number of vaccine development programs that can be pursued at one time. Priorities must be set in a manner that is consistent with both the needs of the population and the capabilities of current technologies. The committee has proposed a method that would allow quantitative comparison of the consequences of various diseases. The system combines information on disease-related illnesses (including incidence, severity, complications, durations, and distributions) and deaths into a single numerical score for each disease. It also allows expression of individual value judgments on the undesirability of different types of illness (morbidity). These value judgments are an inevitable part of the ranking process, whether they are clearly stated or assumed: the committee chose to make them explicit. The first step in the comparison process was to develop a format that would ensure uniform collection of data on the various diseases. The format consists of categories in which to group estimates of the number of cases, complications, and deaths associated with each disease. Three levels of severity were established for both acute and chronic illnesses, and provision was made for recording the durations of acute illnesses. The format was also designed to show the distribution of cases, complications, and deaths among four age groups. Attachment 1 lists eight categories of clinical consequences that may be associated with the diseases and vaccines under consideration. We are compiling estimates for each disease of the annual number of days of morbidity in categories A through C, and the annual number of cases in categories D through H. Determination of the total health impact of each disease requires, however, that these figures be modified to reflect the relative importance of morbidity and mortality at different ages. We are requesting that you prepare a personal, subjective assessment of the relative importance to be assigned to each of the eight categories. Because the relative value may depend on the ages of the afflicted populations, we ask that you provide separate scores for each of four age groups: (1) children under 5 years of age; (2) children

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New Vaccine Development: Establishing Priorities, Volume II, Diseases of Importance in Developing Countries from 5 to 14 years of age; (3) adolescents and adults from 15 to 59 years of age; and (4) adults 60 years of age and older. Additionally, we ask that you estimate the relative importance of the death of a child under 5 years of age to a death in the three higher age groups. The problem of assigning relative importance could be approached in many ways. For the sake of consistency, we ask that you try to work through the exercise as described below. Attachments 2 and 3 are the recording forms for your answers. INSTRUCTIONS FOR COMPLETING THE RECORDING FORM To understand how to complete Attachment 2, please read the following examples. First, consider column 1 of the “Age Related Morbidity and Mortality Trade-offs” table, which refers to illness occurring in children under 5 years of age. For each category, we are seeking a value which can be compared the death of a single young child. For categories A through C, estimate the number of days of illness, and for categories D through G, estimate the number of cases of illness which you think to be as bad as one death of a child. For example, consider category E: moderate to severe chronic (lifelong) disability (see Example 1). You might think that such a EXAMPLE 1: This means that 2 cases of moderate to severe chronic disability are as bad as 1 death.

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New Vaccine Development: Establishing Priorities, Volume II, Diseases of Importance in Developing Countries disability would be almost as bad as dying for a young child. Maybe you think that two cases of moderate to severe disability are equal to one death. Then you would write the number “2” in the space next to category E in column 1. Or maybe you think that children can adapt well to severe disability, and therefore, disability is not as bad as death for a child. You would then be willing to accept a larger number of cases (maybe 25 or more) as equal in value to one death. In that case, you would put a “25” or larger number in the space next to category E in column 1 (see Example 2). EXAMPLE 2: This means 25 cases of moderate to severe chronic disability are as bad as 1 death. In contrast, you might think that severe disability for a young child is worse than death. You might think that 2 deaths are better than 1 case of severe disability. In that case, you consider 0.5 cases of severe disability equal to 1 death (see Example 3). Categories D through G can be completed in this manner. All refer to different types of chronic illnesses, and therefore you can balance the number of cases for each category with the death of one child.

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New Vaccine Development: Establishing Priorities, Volume II, Diseases of Importance in Developing Countries EXAMPLE 3: This means that 0.5 cases of severe chronic disability is equal to 1 death; or 2 deaths are equal to 1 severe chronic disability case. This means that death is preferable to severe chronic disability. Now consider categories A through C. These are categories of acute illness, and therefore are measured in days rather than in cases. For example, category A is “moderate localized pain, minor systemic reaction, or impairment indicating minor change in normal activities.” As before, you want to compare this category to the death of one young child. You would probably use a large number for category A because you are measuring relatively mild consequences in terms of days in each category. Perhaps it is helpful to think that a child under 5 years of age may have a life expectancy of 55 more years, which is equal to 20,000 days. You might think that category A would only make a person unable to work or play for a small part of each day. Therefore you would need a very large number of days of mild illness to be as bad as the death of a young child. Perhaps you would say 150,000 days or more. You would then write the number “150,000” in the space next to category A. Categories A through C can be filled out in this manner. Each category refers to different types of acute illnesses, and therefore you can balance the number of days for each category with the death of a young child.

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New Vaccine Development: Establishing Priorities, Volume II, Diseases of Importance in Developing Countries The examples provided here are to help you understand the information needed for our analysis. There is no right or wrong answer, and your answer may be higher or lower than the examples we have given. After you have completed column 1 (for children under 5 years of age), do the same for the other age categories (columns 2 through 4). Every number written should represent the number of cases (categories D through G) or days (categories A through C) that you think are equal to the death of one person in that age group. INSTRUCTIONS FOR ESTIMATING MORTALITY TRADE-OFF ACROSS AGE GROUPS Attachment 3 asks you to indicate the relative undesirability of deaths in the different age groups. The unit of measure is the death of one child under 5 years of age. The question is how many deaths in each of the other age groups do you believe would balance the death of a young child. You might believe all deaths are equivalent, and mark a “1” in all the spaces; or you might believe a death of an adult (15 to 59 years) is worse than a death of a child and assign a number smaller than 1.0 to such adult deaths (column 3). You might be willing to balance 10 deaths among the elderly (column 4) against one early death. Again, any trade-offs are legitimate as long as they reflect your best personal judgment. EXAMPLE 4: Here, a death in each age group is equivalent. EXAMPLE 5: Here, adult deaths are worse than infant deaths. Ten infant deaths would be equal to one adult death.

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New Vaccine Development: Establishing Priorities, Volume II, Diseases of Importance in Developing Countries EXAMPLE 6: Here, infant deaths are worse than deaths in the elderly. Ten deaths in the elderly are equal to the death of one infant. Please be sure to fill out the entire tables. All answers will be regarded as strictly confidential.

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New Vaccine Development: Establishing Priorities, Volume II, Diseases of Importance in Developing Countries Attachment 1 Morbidity Categories Moderate localized pain and/or mild systemic reaction or impairment requiring minor change in normal activities, and associated with some restriction of work activity. Moderate pain and/or moderate impairment requiring moderate change in normal activities, e.g., house-bound or in bed, and associated with temporary loss of ability to work. Severe pain, severe short-term impairment, or hospitalization Mild chronic disability (not requiring hospitalization, institutionalization, or other major limitation of normal activity, and resulting in minor limitation of ability to work). Moderate to severe chronic disability (requiring hospitalization, special care, or other major limitation of normal activity, and seriously restricting ability to work). Total impairment. Reproductive impairment resulting in infertility. Death.

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New Vaccine Development: Establishing Priorities, Volume II, Diseases of Importance in Developing Countries Attachment 2 Age Related Morbidity and Mortality “Trade-Offs”   Column   1 2 3 4   Category Unit Under 5 Years 5–14 Years 15–59 Years 60 Years and Over A. Moderate localized pain and/or mild systemic reaction or impairment requiring minor change in normal activities, and associated with some restriction of work activity Days   B. Moderate pain and/or moderate impairment requiring moderate change in normal activities, e.g., house-bound or in bed, and associated with temporary loss of ability to work Days   C. Severe pain, severe short term impairment, or hospitalization Days   D. Mild chronic disability (not requiring hospitalization, institutionalization, or other major limitation of normal activity, and resulting in minor limitation of ability to work Cases   E. Moderate to severe chronic disability (requiring hospitalization, special care, or other major limitation of normal activity, and seriously restricting ability to work) Cases   F. Total impairment Cases   G. Reproductive impairment resulting in infertility Cases   H. Death Cases 1 1 1 1   Deaths   1  

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New Vaccine Development: Establishing Priorities, Volume II, Diseases of Importance in Developing Countries Attachment 3 Age Related Mortality “Trade-Offs”