The cost-effectiveness of whole-blood NAT is poor. The testing cost would need to decrease significantly to bring the cost-effectiveness in line with most other accepted medical practices.

No abstract

Little information is available regarding the risk of human immunodeficiency virus type 1 (HIV-1) infection for patients transfused before routine anti-HIV-1 screening of blood donors was instituted in March 1985. A model was developed for estimating both the proportion and the number of transfusion recipients in the San Francisco Bay area who were infected by HIV-1 during each of the 7 years preceding routine donor screening for anti-HIV-1. The model is based on analysis of 1) donation histories of HIV-1-infected donors identified at the regional blood center; 2) HIV-1 seroprevalence estimates for homosexual and bisexual men in San Francisco; and 3) HIV-1 infection and survival rates for recipients traced by the Transfusion Safety Study and Irwin Memorial Blood Centers' Look Back Program. The incidence of transfusion-associated HIV-1 infection is estimated to have risen rapidly from the first occurrence in 1978 to a peak in late 1982 of approximately 1.1 percent per transfused unit. The decrease after 1982 coincided with the implementation of high-risk donor deferral measures. It is estimated that, overall, approximately 2135 transfusion recipients were infected with HIV-1 in the San Francisco region alone. This number suggests a higher prevalence of transfusion-associated HIV-1 infection than has been generally recognized and indicates the need for continued tracing of potentially exposed recipients. The data also strongly support the effectiveness of early donor education and self-exclusion measures and emphasize the importance of continued research and development in this area.

Although expanding the donor HIV screening protocol with p24 antigen or RNA PCR testing will prevent rare cases of transfusion-associated HIV, the cost-effectiveness of such an addition is predicted to be far below that of most medical interventions. Thus, HIV test protocol additions are unlikely to provide cost-effective improvements to blood safety in the United States.

The crude HBV incidence rate observed from HBsAg test results will underestimate the true rate. The adjusted HBV incidence rate should be used in applications such as estimations of residual HBV risk to the blood supply and projections of the benefits of screening for HBV DNA.

The window period averages 45 days, with few, if any, donors remaining infectious and seronegative for longer than 6 months.

Transmission of the common commensal anelloviruses and GBV-C during transfusion was detected in 2 of 12 already infected or uninfected recipients. Underestimation of the true rate of viral transmission may be due to limitations in detecting donor viral variants present as minority variants in the already infected transfusion recipients.

The finding that no donation studied was positive for p24 antigen and negative for HIV-1 antibody suggests that screening donors for p24 antigen with tests of the current level of sensitivity would not add substantially to the safety of the U.S. blood supply.