Application of the BED capture enzyme immunoassay for HIV incidence estimation among female sex workers in Kaiyuan City, China, 2006-2007.
OBJECTIVE
To estimate HIV incidence among female sex workers (FSWs) by serial cross-sectional surveys and IgG-capture BED-enzyme immunoassay (BED-CEIA).


METHODS
We conducted three cross-sectional surveys, 6 months apart, among all consenting FSWs in Kaiyuan City, China. HIV antibody-positive samples were also tested by BED-CEIA.


RESULTS
Among 1412 unique participants, 475 tested HIV-negative and attended >1 survey (longitudinal cohort). Compared to 786 HIV-negative FSWs who only participated once, the longitudinal cohort reported more illicit drug use (10.9% vs. 7.4%, p=0.03), injected drugs more often in the previous 3 months (8.8% vs. 5.3%, p=0.02), and had more positive urine opiate tests (13.7% vs. 8.9%, p=0.008). Four participants in the longitudinal cohort seroconverted over the year, with an overall incidence of 1.1/100 person-years (95% confidence interval (CI) 0.3-2.8). Crude BED-CEIA incidence was 3.4/100 person-years (95% CI 2.3-4.4) with adjusted rates similar to the cohort incidence: McDougal, 1.5/100 person-years (95% CI 1.0-2.0); Hargrove, 1.6/100 person-years (95% CI 1.1-2.1). The BED-CEIA false-positive rate was 4.4% (10/229) among samples from FSWs known to be infected > or =365 days.


CONCLUSIONS
Although limited by power, this study provides additional data towards validating BED-CEIA in China. If confirmed by other studies, BED-CEIA will be a useful tool to estimate HIV incidence rates and trends.
Xu
Junjie
J
National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, 27 Nanwei Road, Beijing, China.
Wang
Haibo
H
Jiang
Yan
Y
Ding
Guowei
G
Jia
Manhong
M
Wang
Guixiang
G
Chu
Jennifer
J
Smith
Kumi
K
Sharp
Gerald B
GB
Chen
Ray Y
RY
Jin
Xia
X
Dong
Ruiling
R
Han
Xiaoxu
X
Shang
Hong
H
Wang
Ning
N
D000328:Adult; D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D015483:HIV Antibodies / Q000097:blood*; D015658:HIV Infections / Q000453:epidemiology* / Q000821:virology; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods; D007074:Immunoglobulin G / Q000097:blood; D015994:Incidence; D011477:Sex Work; D055815:Young Adult
D015483:HIV Antibodies; D007074:Immunoglobulin G