The incidence and prevalence of HIV infection among childbearing women living in Edinburgh city, 1982-1995

Application of human immunodeficiency virus type 1 BED enzyme immunoassay on dried blood spots in India

Dried blood spots (DBSs) on filter paper are being used increasingly in population-based human immunodeficiency virus (HIV) studies. This study evaluated the application of a BED enzyme immunoassay (EIA) on DBSs to estimate HIV incidence in a population-based study in India. The Calypte HIV-1 BED Incidence EIA was performed on 224 HIV-1-positive DBS samples, after screening 12 617 individuals from a population-based sample in Guntur district in the southern Indian state of Andhra Pradesh. The number of recently infected HIV cases was identified using this BED assay and was used to estimate the annual HIV incidence rate based on calculations and adjustment formulae suggested by the Centers for Disease Control and Prevention (CDC). The updated BED data management software provided by the CDC was used for analyses. Of the 224 HIV-1 antibody-positive DBS samples, 29 (12.95 %) were estimated by the BED HIV-1 assay to have been infected within the past 155 days. After adjusting for age, gender and rural/urban distribution of the population, the annual incidence rate of HIV-1 infection was estimated to be 0.32 % (95 % confidence interval 0.20–0.44 %). This annual incidence was 18.6 % of the HIV prevalence of 1.72 % in this study. Thus, the BED assay revealed a higher incidence of HIV in this study than was expected from the prevalence. Correlation of the BED assay with panel testing and longitudinal incidence data in the Indian population is needed to calibrate it for use in India.

Using HIV voluntary counseling and testing data for monitoring the Uganda HIV epidemic, 1992-2000

OBJECTIVE

To assess trends in the prevalence of HIV infection among voluntary counseling and testing (VCT) clients in Uganda and to describe the utility of VCT data for monitoring the HIV epidemic in 1992-2000.

METHODS

We analyzed routinely collected data from first-time VCT clients not reporting illness as a reason for testing. We developed a model adjusting for test site, couple testing, and premarital testing, assessed trends in adjusted prevalence of HIV infection and shifts in age-specific peak prevalence, and compared antenatal clinic (ANC) surveillance data and VCT prevalence trends.

RESULTS

Among 201,741 clients, adjusted prevalence of HIV infection declined from 23% in 1992 to 13% in 2000 (P < 0.001) (men, 17%-9% [P < 0.001]; women, 31%-18% [P < 0.001]). The prevalence declined for all age groups except men older than 39 years and women older than 34 years. The prevalence increased for women older than 39 years (P < 0.003). Between 1992 and 2000, peak prevalence declined for both men (31% to 24%) and women (44% to 41%), whereas the age at which the peak occurred increased for both men (36 to 41 years) and women (31 to 36 years). VCT and ANC prevalence trends were similar.

CONCLUSION

In Uganda, the prevalence of HIV infection among male and female VCT clients declined from 1992 to 2000, similar to ANC surveillance data, but did not decline in older age groups. In regions with well-established VCT programs, VCT data may provide a useful and convenient tool for monitoring the HIV epidemic.

Development and validation of an immunoassay for identification of recent human immunodeficiency virus type 1 infections and its use on dried serum spots

The objective was to develop and to validate an immunossay to identify recent human immunodeficiency virus type 1 (HIV-1) infections that can be used on dried serum spots (DSS). A single, indirect enzyme-linked immunosorbent assay was developed to quantify antibodies toward four HIV-1 antigens: consensus peptides of the immunodominant epitope of gp41 (IDE), consensus V3 peptides, recombinant integrase, and recombinant p24. The parameters of the logistic regression used to classify the samples were estimated on a training sample (210 serum samples) using resampling techniques to get stable estimates and then applied to a validation sample (761 serum samples). The IDE and V3 peptides were the best able to discriminate between the antibodies present in serum from recently (< or =6 months) infected individuals and those with long-lasting infection. Combined quantification of antibody binding to these two synthetic antigens allowed us to identify recent infections with an area under the receiver operating characteristic curve of 0.949 and a sensitivity of 88.3%, with a specificity of 97.6% in patients with long-term infection (but not AIDS) and 86.0% in patients suffering from AIDS with a threshold of 0.50 in the validation sample. This simple immunoassay can be used to identify recently HIV-1-infected patients. Its performance is compatible with its use in population-based studies including DSS.

Risk of HIV transmission from patients to surgeons in the era of post-exposure prophylaxis

The HIV prevalence, among patients either undergoing, or with the potential to undergo, surgery were estimated using data from unlinked anonymous HIV surveys of patients in Glasgow hospitals during 1992-1997 in order to quantify the risk of surgeons acquiring HIV occupationally in the era of post-exposure prophylaxis (PEP) availability. A range of prevalence rates was applied to data on other factors influencing risk; these comprised, i) the probability of a percutaneous injury from a sharp instrument used on an HIV infected patient resulting in HIV transmission, ii) the number of injuries sustained and iii) whether or not PEP was administered. On the basis of, for example, a surgeon sustaining three percutaneous injuries over 12 months and not taking PEP after each, the annual risks ranged from 1 in 2,000,000 for urological/renal surgeons to 1 in 200,000 for those performing general surgery/ENT/gynaecological procedures. The administration of PEP after each injury would reduce these rates to 1 in 10,000,000 and 1 in 1,000,000 respectively. The risk of surgeons acquiring HIV occupationally in a city which has an HIV prevalence typical of most urban areas in the UK, is 'minimal' or 'negligible'. In the context of such low risk and our limited knowledge of the adverse effects of PEP, the risk assessment to decide whether or not to give PEP should be well informed and consistent. Current guidelines to help physicians and affected healthcare workers in their decision making need to be improved.