Evaluation of FDA licensed HIV assays using plasma from Cameroonian blood donors

[HIV infection and immigration]

Migrants represent around one third of patients newly diagnosed with HIV in Spain and they constitute a population with higher vulnerability to its negative consequences due to the socio-cultural, economical, working, administrative and legal contexts. Migrants are diagnosed later, which worsens their individual prognosis and facilitates the maintenance of the HIV epidemic. In spite of the different barriers they experience to access healthcare in general, and HIV-related services in particular, access to antiretroviral treatment has been similar to that of the autochthonous population. However, benefits of treatment have been not, with women in general and men from Sub-Saharan Africa exhibiting the worse response to treatment. We need to proactively promote earlier diagnosis of HIV infection, the adoption of preventive measures to avoid new infections, and to deliver accessible, adapted and high-quality health-care.

Transfusion safety in francophone African countries: an analysis of strategies for the medical selection of blood donors

BACKGROUND

The goal of selecting a healthy blood donor is to safeguard donors and reduce the risks of infections and immunologic complications for recipients.

STUDY DESIGN AND METHODS

To evaluate the blood donor selection process, a survey was conducted in 28 blood transfusion centers located in 15 francophone African countries. Data collected included availability of blood products, risk factors for infection identified among blood donor candidates, the processing of the information collected before blood collection, the review process for the medical history of blood donor candidates, and deferral criteria for donor candidates.

RESULTS

During the year 2009, participating transfusion centers identified 366,924 blood donor candidates. A mean of 13% (range, 0%-36%) of the donor candidates were excluded based solely on their medical status. The main risk factors for blood-borne infections were having multiple sex partners, sexual intercourse with occasional partners, and religious scarification. Most transfusion centers collected this information verbally instead of having a written questionnaire. The topics least addressed were the possible complications relating to the donation, religious scarifications, and history of sickle cell anemia and hemorrhage. Only three centers recorded the temperature of the blood donors. The deferral criteria least reported were sickle cell anemia, piercing, scarification, and tattoo.

CONCLUSIONS

The medical selection process was not performed systemically and thoroughly enough, given the regional epidemiologic risks. It is essential to identify the risk factors specific to francophone African countries and modify the current medical history questionnaires to develop a more effective and relevant selection process.

Development of a World Health Organisation International Reference Panel for Anti-HIV

In response to a recommendation made by the "World Health Organisation (WHO) Working Group on Reference Preparations for Testing HBsAg, Anti-HCV and Anti-HIV Diagnostic Kits", a reference panel for anti-HIV consisting of plasma samples representing the major groups and subtypes of HIV has been prepared. The panel consists of solvent-detergent treated anti-HIV-positive human plasma samples that have been diluted 1 in 40 in anti-HIV-negative human serum and freeze-dried and the anti-HIV-positive plasma samples were derived from individuals infected with HIV-1 group M subtypes A, B, C and CRF01_AE, HIV-1 group O and HIV-2. Fifteen laboratories from around the world took part in a collaborative study to evaluate the reference panel for anti-HIV and were requested to test the panel in as wide a range of assays as possible. Where appropriate, serial dilutions were performed and samples tested around their end-points to facilitate the comparison of analytical sensitivity between assays. For qualitative assays such as Western blots and rapid assays, the panel was tested undiluted. Results show that the HIV-negative serum sample was negative in all assays (except for a small number of Western blot assays) and that all HIV-positive samples were detected in all assays, with the exception of an anti-HIV-2 EIA that did not detect most HIV-1 samples and a small number of assays that failed to detect the group O sample. Considerable variability was seen in the end-point titres obtained with the various assays. A report on the study was submitted to the WHO Expert Committee on Biological Standardisation (ECBS) and the panel established as the 1st International Reference Panel for Anti-HIV (code 02/210); a unitage was not assigned to the panel members.

Field evaluation of Calypte's AWARE blood serum plasma (BSP) and oral mucosal transudate (OMT) rapid tests for detecting antibodies to HIV-1 and 2 in plasma and oral fluid

As programs to prevent and care for HIV-infected persons are scaled-up in Africa, there is the need for continuous evaluation of the performance of test kits that could best support these programs. The present study evaluated the sensitivity, specificity, ease of use, and cost of AWARE ^™ Blood Serum Plasma (BSP) and Oral Mucosal Transudate (OMT) Rapid HIV-1/2 test kits using real-time and archived samples of HIV-infected persons from Cameroon. Matched whole blood and OMT specimens were collected prospectively from HIV-positive and HIV-negative persons from different regions of Cameroon and tested using the AWARE ^™ BSP and OMT test kits, respectively. These results were compared to the gold standard that included a combination of Determine HIV-1/2 and Enzygnost HIV-1/2. The BSP Rapid test kit was further evaluated using well characterized panels of HIV-2 and HIV-1 group O samples. Cost and end-user analysis of the OMT test kit was done by comparing its actual cost, consumables, safety, bench time and manipulation with other test kits. Of the 732 matched samples, 412 (56.3%) and 320 (43.7%) were from females and males, respectively. Of these samples, 23 (3.1%) gave discordant results between Determine HIV-1/2 and Enzygnost HIV1/2 and were excluded from the analysis. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the AWARE^™ BSP were 100%. The AWARE^™ OMT had 98.8% sensitivity, 98.9% specificity, 98.0% PPV and 99.4% NPV. The results of a well-characterized archived panel of HIV-2 (n=7) and HIV-1 group O (n=3) samples using the AWARE^™ BSP Rapid test kit gave 100% concordance. Total per patient cost of the AWARE OMT rapid test kit was US$4.72 compared to a mean cost of US $7.33 ± 0.11 for the other test kits. Both the AWARE^™ BSP and OMT Rapid test kits demonstrated high sensitivities and specificities on all samples tested and were well adapted for use in resource-constrained settings with high HIV heterogeneity such as Cameroon. The AWARE ^™ HIV-1/2 OMT Rapid test kit appears to be the cheapest, safest and easiest to use compared with other available test kits.