Xiao Y

HIV-1 incidence estimates using IgG-capture BED-enzyme immunoassay from surveillance sites of injection drug users in three cities of China.

Objective:To detect recent infection in injection drug users (IDU) using the HIV-1 subtypes B, E, and D IgG-capture enzyme immunoassay (BED-CEIA) and estimate HIV-1 incidence in the IDU population in three cities of China. Design:HIV-1-positive samples from IDU surveillance sentinel sites were collected for BED-CEIA, including 215 from city C (2001–2006), 433 from city D (2005), and 912 from city E (2000–2003). All 1560 samples were confirmed HIV positive with Western blot or alternative strategy. Methods:HIV-1 incidence was calculated with BED-CEIA statistics software. Results:City C: Annualized HIV-1 incidence among IDU of surveillance sentinel sites was 0.57–0.93% from 2000 to 2001, and approximately 1.0% from 2004 to 2006. City D: In IDU surveillance sentinel sites in 2005, the HIV-1 incidence was estimated to be 9.6%, whereas the incidence in all drug users was 2.1%. City E: IDU sentinel surveillance indicated a slight decrease in HIV-1 incidence from 9.2% in 2000 to 7.9% in 2003. Conclusion:The HIV-1 incidence in IDU in city C was stable and relatively low. In contrast, there is a high HIV-1 incidence among IDU in cities D and E. The adjusted BED-CEIA estimated incidence rates indicate clearly that interventions must be strengthened continuously in IDU, especially in two Chinese cities.

Estimation of HIV-1 incidence among five focal populations in Dehong, Yunnan: a hard hit area along a major drug trafficking route

BackgroundSince 1989 when the first 146 HIV positives in China were identified, Dehong Prefecture had been one of the areas hardest-hit by HIV in China. The local and national governments have put substantial financial resources into tackling the HIV epidemic in Dehong from 2004. The objective of this study was to track dynamic changes in HIV-1 prevalence and incidence among five focal populations in Dehong and to assess the impact of HIV prevention and control efforts.MethodsConsecutive cross-sectional surveys conducted in five focal populations between 2004 and 2008. Specimens seropositive for HIV were tested with the BED IgG capture enzyme immunoassay to identify recent seroconversions (median, 155 days) using normalized optical density of 0.8 and adjustments.ResultsFrom 2004 to 2008, estimated annual HIV incidence among injecting drug users (IDUs) decreased significantly [from 15.0% (95% CI = 11.4%-18.5%) in 2004 to 4.3% (95% CI = 2.4%-6.2%) in 2008; trend test P < 0.0001]. The incidence among other focal populations, such as HIV discordant couples (varying from 5.5% to 4.7%), female sex workers (varying from 1.4% to 1.3%), pregnant women (0.1%), and pre-marital couples (0.2 to 0.1%) remained stable. Overall, the proportion of recent HIV-1 infections was higher among females than males (P < 0.0001).ConclusionsThe HIV epidemic in Dehong continued to expand during a five-year period but at a slowing rate among IDUs, and HIV incidence remains high among IDUs and discordant couples. Intensive prevention measures should target sub-groups at highest risk to further slow the epidemic and control the migration of HIV to other areas of China, and multivariate analysis is needed to explore which measures are more effective for different populations.

Seroincidence of Recent Human Immunodeficiency Virus Type 1 Infections in China

ABSTRACT A subtype B, E, and D immunoglobulin G capture immunoassay shows promise as a tool for estimating human immunodeficiency virus type 1 seroincidence from cross-sectional surveys, but the test-specific limitations suggest that an adjustment is necessary, and further validation of the assay with populations with divergent subtypes is needed.

Evaluation of PIMA point-of-care CD4 analyzer in Yunnan, China.

Background: CD4 count is used to determine antiretroviral therapy (ART) eligibility. In China, flow cytometers are mostly located in urban areas with limited access by patients residing in remote areas. In an attempt to address this issue, we conducted a study to validate the performance of Alere PIMA point-of-care CD4 analyzer. Methods: Venous and finger-prick blood specimens were collected from HIV-positive participants from two voluntary counseling and testing sites in Yunnan Province. Both venous and finger-prick blood specimens were tested with the PIMA analyzer. Venous blood specimens tested with the Becton Dickinson FACSCalibur were used as a reference. Results: Venous specimens from 396 and finger-prick specimens from 387 persons were available for analysis. CD4 counts by PIMA correlated well with those from FACSCalibur with an R 2 of 0.91 for venous blood and 0.81 for finger-prick blood. Compared to FACSCalibur, the PIMA analyzer yielded lower counts with a mean bias of − 47.0 cells/&mgr;l (limit of agreement, [LOA]: −204–110 cells/&mgr;l) for venous blood and −71.0 cells/&mgr;l (LOA: −295–153 cells/&mgr;l) for finger-prick blood. For a CD4 threshold of 350 cells/&mgr;l, the positive predictive value (PPV) of PIMA was 84.2% and 75.7% and the negative predictive value (NPV) was 97.6% and 95.8% for venous and finger-prick blood, respectively. For an ART threshold of 500 cells/&mgr;l, the corresponding PPV was 90.3% and 84.0% and NPV was 94.3% and 93.4%, respectively. Conclusions: CD4 counting using venous blood with PIMA analyzers is a feasible alternative to a large flow cytometer to determine ART eligibility.