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1. Effectiveness of the workshops:

The efficacy of the workshops in reducing transmission rates is claimed at 50%. This means that if the rate of new cases in the plant is 4 per 100, then the Wola Nani programme will reduce it to 2 per 100. The workshops may also encourage participants to become more involved in HIV education amongst their peers.

Make the following assumptions to estimate the numbers of workers in the plant developing HIV and/or AIDS:

There is no labour turnover at the factory over the next 5 years other than related to HIV effects. In other words, no one joins the workforce or leaves for reasons unrelated to HIV.
Assume a prevalence of 10% of the workforce are currently HIV infected and that this rate will increase to 20% over the next 2 years without intervention. In other word, 5% of the workforce each year will seroconvert (crude assumption).
The median time to boarding once a person has AIDS is 6 months.
The median time to death once you have AIDS is 12 months.
However, HIV-infected persons may remain HIV positive without progression to AIDS with good treatment for up to 5 years (median).
About 20% of HIV infected persons will progress to AIDS within one year and another 15% to AIDS within the second year after diagnosis.

This data have been used to complete the tables below. Table 1 maps the numbers of HIV cases saved as a result of the intervention:

**TABLE 1**
	Baseline cases (10% prevalence)	New cases in year one	New cases in year two
No intervention	95	48	48
Intervention	95	24	24
Cases saved by intervention		24	24

Table 2 maps the progression to HIV and/or death that would have taken place of those cases saved by the HIV intervention. Two hypothetical cohorts are traced over the next five years, representing the cases that would have been saved by the intervention in year one and year two, respectively. It is based on the assumption that 20% of HIV infected persons will progress to AIDS within one year and another 15% to AIDS within the second year after diagnosis, and that media time for progression to AIDS with good treatment is 5 years.

Once someone has AIDS, median duration to boarding is 6 months and to death 12 months. Table 2 has been completed for you based on these assumptions.

**TABLE 2**
Cohort	HIV status	Year 0	Year 1	Year 2	Year 3	Year 4	Year 5	Cumulative total at Year 5
Cohort 1	HIV	24	19	16	14	13	12	98
	AIDS		5	6	5	3	2	21
	Death			2	3	3	2	10
Cohort 2	HIV		24	19	16	14	13	86
	AIDS			5	6	5	3	19
	Death				2	3	3	8

Note:

The number of HIV person years saved that were accumulated in total over the 5 year period.
The number of AIDS person-years saved that were accumulated in total over the 5-year period.
The number of deaths due to AIDS that occurred over the 5-year period.

2. Benefits related to morbidity and mortality prevented:

Now look at benefits saved for each HIV person-year, AIDS person-year and AIDS death averted. Make the following assumptions in calculating benefits:

Illness absenteeism at the workforce is presently about 8%. Data in the literature suggest that HIV infected people (without AIDS) experience about twice as much illness absenteeism as non-HIV infected persons. Once they have AIDS, their absenteeism rates will increase 10-fold.
Marginal costs of medical care to the company for every HIV-infected person are about R 6000 per year.
The nett costs to the company (through insurance claims) for an HIV-related death are on average R 200 000. This represents the average productivity loss due to HIV-related deaths in the future.

Use this data to fill in the data in the table for absenteeism and death-related productivity loss. Absenteeism is the number of days absent (off work for debility or incapacity) as a proportion of all potential working days. It is counted as a cost/benefit since employees receive sick pay whilst not productive.