How cost-effective is blood screening in preventing secondary HIV infections? One answer to this question can be seen in the results of the Uganda Blood Transfusion Service (UBTS) for 1993. Having established its ability to supply Kampala with clean blood in 1991, by 1993 the UBTS was reaching out to cover the entire country. That year the service transfused 20,156 patients throughout the country at an average cost of approximately $38 per unit of blood, and an average of 1.2 units per patient, for a total budget of approximately $929,900. Box table 4.2 breaks out the HIV prevention benefits of the service, showing that its use averted HIV infection in an estimated 1,863 surviving transfusion recipients.
But to measure the positive externalities of the program, and thus the rationale for government subsidies, we need to look beyond these primary infections to consider secondary infections. Children who are infected by transfusion are unlikely to live long enough to infect others, but some of the adults may be sufficiently young and sexually active to engage in risky sexual behavior later in their lives. Since many of these people are quite sick, the evaluation study estimated that each of these adults would have only a 50 percent chance of infecting one other person with HIV (European Commission 1995). Thus the total number of secondary infections averted would be 415.1 If the entire justification of the blood supply service is prevention of these secondary infections, the cost-effectiveness of the service is $929,900 divided by 415, or $2,240 per such infection averted. If Uganda had had a sustainable blood supply system, the cost of preventing these 415 infections would have been only $319,894, or $771 each. This much smaller amount is still substantially larger than the cost of preventing secondary infections in other ways (see box 2.6).
1 The authors point out that the counseling provided to blood donors may have averted additional primary infections (European Commission 1995). Any secondary infections averted through this route should be added to the 415 to compute the total positive externalities of the program.
Box Table 4.2 Effectiveness of Blood Transfusion at Averting HIV Infection, Uganda, 1993
Benefits |
|||
| Effects of blood transfusions | Children | Adults | Total |
| Patients transfused | 11,515 |
8,641 |
20,156 |
| Patients expected to die without transfusion | 5,758 |
3,898 |
9,656 |
| Patients who died despite transfusion | 3,801 |
2,592 |
6,393 |
| Number of deaths prevented | 1,957 |
1,296 |
3,253 |
| Number of primary HIV infections prevented | 1,033 |
830 |
1,863 |
| Number of secondary HIVinfections prevented | 0 |
415 |
415 |
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