BED Capture Enzyme Immunoassay Research Articles

High prevalence and incidence of human immunodeficiency virus 1 among men who have sex with men at the voluntary counselling and testing center in Northeast Brazil

The human immunodeficiency virus (HIV) Brazil epidemic had shown an increase in heterosexual transmission and decrease in vertical transmission. However, its incidence has increased among men who have sex with men. Serological screening of patients at a voluntary counselling and testing center in Cabo de Santo Agostinho city, Pernambuco province, Northeast Brazil, was performed to determine the HIV-1 prevalence and incidence. The HIV-1 incidence in the frozen serum aliquots obtained from 2006-2009 was determined using BED-capture enzyme immunoassay. This study evaluated 23,862 individuals, who were serologically tested for HIV-1. HIV-1 infection was diagnosed in 318 individuals (1.33%). MSM showed a higher prevalence of infection (6.8%; 95% confidence interval [CI]: 4.9-9.5) as compared to heterosexual men (2.8%; 95% CI: 2.35-3.36) and women (0.9%; 95% CI: 0.76-1.0) (p < 0.0001). MSM also showed a higher rate of incidence with 3.93 per 100 people/year. Early diagnosis and preventive measures can reduce the pandemic spread.

Syphilis seroprevalence and seroconversion among people newly diagnosed with HIV during the pre-antiretroviral therapy period in rural China

Syphilis has a high incidence among people living with HIV (PLHIV), which may be attributable to their similar sexual transmission route. A retrospective cohort study was conducted during the period 2009-2015 to investigate the syphilis seroprevalence and incidence of syphilis seroconversion among newly-diagnosed PLHIV in rural Yunnan, China. Recent HIV infection among PLHIV was identified by BED capture enzyme immunoassay. PLHIV were followed until they initiated antiretroviral therapy. Syphilis serology was conducted at baseline and each follow-up over the study period. Among 2162 participants, the syphilis seroprevalence at baseline was 2.7%, 95% confidence interval (CI) (2.4-3.1). Single and divorced (versus married) (aOR = 2.9, [1.1-7.4]; 5.9, [2.4-14.7], respectively), employed in the service industry (versus unemployed) (2.8, [1.4-5.6]), being diagnosed with HIV in hospitals (versus voluntary counselling and testing) (5.1, [2.0-12.9]), recent HIV infection (17.9, [8.5-37.9]) and inconsistent condom use in the previous three months (versus consistent condom use) (6.2, [2.8-13.4]) were associated with higher risk of syphilis infection at baseline. Participants contributed 1955.4 person-years (PYs) of follow-up, with a median follow-up period of 0.9 years (IQR: 0.5-1.9) and the incidence of syphilis seroconversion was 2.2 (95% CI 1.5-2.9) per 100 PYs. The syphilis seroprevalence at baseline (aHR 3.7, [1.8-7.9]), had a HIV-negative partner at baseline (3.9, [1.5-9.8]) and inconsistent condom use in the last three months at baseline (6.0, [1.4-25.4]) were associated with higher risk of syphilis seroconversion. Our findings indicate that the public health response should be escalated to minimise the spread of syphilis co-infection among PLHIV and reducing condomless sexual behaviours after HIV diagnosis.

The changing modes of human immunodeficiency virus transmission and spatial variations among women in a minority prefecture in southwest China: An exploratory study.

Liangshan Yi Autonomous Prefecture in Southwest China has a high human immunodeficiency virus (HIV) prevalence rate. This study examined the changing modes of HIV transmission among women with new HIV infections and explored the spatial heterogeneities in the factors associated with heterosexual transmission in this minority region.The data consisting of women with new HIV infections from 2011 to 2014 were collected from multiple sources. New infections were identified by BED capture enzyme immunoassay. The Bayesian hierarchical model was used to estimate the proportion of women with new HIV infections via heterosexual transmission across all townships in the Prefecture. A geographically weighted regression (GWR) model was utilized to investigate spatial variations in the sociodemographic characteristics associated with the changing modes of HIV transmission.An analytical sample of 927 women with new HIV infections was constructed and utilized to investigate the changing mode of HIV transmission. The rate of heterosexual transmission among women with new HIV infections in 2011 was below 20%. However, by 2014 this rate dramatically increased to nearly 80%. Among sociodemographic characteristics, GWR results revealed significant ethnic differences in heterosexual HIV transmission between Yi women and women in other ethnic groups, with Yi women demonstrating a lower risk of infection through heterosexual transmission. However, such ethnic differences were observed only in 30% of the townships in the Prefecture. Moreover, having a primary education decreased the odds of heterosexual transmission, which was observed in about 56% of the townships. Also, being involved in occupations other than agriculture or animal husbandry and being single or married decreased the odds of HIV infection through heterosexual contact among women, which did not significantly vary across the Prefecture.Heterosexual transmission was the predominant mode of HIV transmission among women in the Prefecture, and this transformation was clearly marked by a fast-growing trend and a spatial diffusion pattern. Spatial variations also existed in sociodemographic factors that were associated with the changing modes of HIV transmission.

Spatial clusters of HIV-1 genotypes in a recently infected population in Yunnan, China

BackgroundAs a gateway for HIV-1 in China, Yunnan has experienced dramatic changes in HIV-1 epidemics, during which HIV-1 genotypes have become complex. To track dynamic changes in HIV-1 genotypes, an HIV-1 molecular epidemiological study was implemented in the recently infected population in Yunnan.MethodsFrom 6,357 HIV-1-positive samples diagnosed during the first half of 2015 in Yunnan, 586 samples were identified as recent infections with BED-capture enzyme immunoassay (CEIA) and were subjected to phylogenetic analyses. Spatial scanning analyses for the main HIV-1 genotypes were also performed.ResultsAmong the 439 specimens successfully genotyped, more than ten genotypes were detected, including CRF08_BC (45.3%), CRF07_BC (19.4%), unique recombinant forms (URFs) (18.2%), CRF01_AE (11.4%), subtype C (2.1%), CRF85_BC (1.1%), CRF55_01B (0.9%), subtype B (0.5%), CRF64_BC (0.5%), CRF59_01B (0.2%), CRF83_cpx (0.2%) and CRF87_cpx (0.2%). Females, Chinese, heterosexual contact and intravenous drug injection were significantly associated with CRF08_BC infection; homosexual contact was significantly associated with CRF01_AE and CRF07_BC infection; males and non-Chinese had a higher risk of URF infection than females. Among all HIV-1 genotypes, the geographic coverage of CRF08_BC was the largest. For CRF08_BC, CRF07_BC, URFs and CRF01_AE, spatial clusters were detected. The two CRF08_BC clusters and one URF cluster were associated with heterosexual transmission, and two of CRF01_AE clusters were associated with homosexual transmission. Transmitted drug resistance (TDR)-associated mutations were detected in 2.4% of individuals.ConclusionsThe diversity of HIV-1 genotypes increased in recent infections because of a long-term HIV-1 epidemic in Yunnan. The predominant HIV-1 strains showed distinct demographic characteristics and formed spatial clusters. These findings improved our understanding of the evolution of HIV-1 in Yunnan and provided information for further HIV-1 control and prevention.

Trends of HIV incidence and prevalence among men who have sex with men in Beijing, China: Nine consecutive cross-sectional surveys, 2008-2016.

BackgroundSexual transmission of HIV among men who have sex with men (MSM) increased markedly in China during the past decade. HIV incidence is a critical indicator in HIV surveillance and we use a HIV-1 BED-capture-enzyme immunoassay (BED-CEIA) to examine the incidence among MSM in Beijing from 2008 to 2016. Risk factors related to recent HIV infection were also assessed.MethodsConsecutive cross-sectional surveys on MSM were conducted yearly from 2008 through 2016. Demographic and behaviors data were collected. HIV status was determined and HIV positive specimens were tested for recent infection using BED-CEIA. Specimens with ODn values≤0.8 were considered recently infected, HIV incidence rates and prevalence were then calculated. Risk factors associated with recent HIV infection were assessed by univariate and multivariable logistic regression.ResultsFrom 2008 to 2016, the numbers of eligible participants in the nine consecutive years ranged from 472 to 616. All the 261 eligible HIV-positive specimens were subjected to recent HIV infection testing. HIV prevalence ranged from 5.0% (3.3%-6.8%) to 10.2% (7.8%-12.7%), and incidence ranged from 1.57% (0.19%-2.95%) to 6.63% (3.65%-9.61%). MSM who never or sometimes used condoms during anal sex with men in the past 6 months (aOR = 1.515, 95%CI: 1.016–2.257, p = 0.041), or having syphilis infection (aOR = 1.561, 95%CI: 0.946–2.575, p = 0.081) were more likely to be recently infected with HIV. Being a Beijing resident (aOR = 0.409, 95%CI: 0.212–0.790, p = 0.008), or having only one male anal sex partner in the past 6 months (aOR = 0.467, 95%CI: 0.220–0.994, p = 0.048) were associated with a lower risk for recent HIV infection.ConclusionsThe HIV incidence fluctuated among MSM in Beijing. Unprotected anal sex, having multiple sex partners, being a non-registered Beijing resident and having a syphilis infection play important roles in the recent HIV infection. Effective intervention measures for HIV and syphilis control and prevention should be continuously strengthened.

Surveillance of recent HIV infections among newly diagnosed HIV cases in Germany between 2008 and 2014

BackgroundThe HIV surveillance system in Germany is based on mandatory, anonymous notification of newly diagnosed HIV cases by laboratories. Because the time between HIV infection and the diagnosis of HIV varies widely between persons, it is difficult to determine the number of cases of recent HIV infection among newly diagnosed cases of HIV. In Germany, the BED-capture-enzyme immunoassay (BED-CEIA) has been used to distinguish between recent and long-standing HIV infection. The aim of this analysis is to report the proportion of cases of recent HIV infection among newly diagnosed cases in Germany between 2008 and 2014 and to identify factors associated with recent infections.MethodsA sample of voluntary laboratories among all HIV diagnostic laboratories was recruited. Residual blood from HIV diagnostic tests was spotted on filter paper as dried serum or dried plasma spots and was sent along with the notification form of the HIV cases. The BED-CEIA test was performed. A case was defined as recent HIV infection with a BED-CEIA test result of less than 0.8 normalized optical density, with the exclusion of CDC stage C. The proportion of recent newly diagnosed HIV infections among different groups (such as transmission groups, gender or age groups) was calculated. We used logistic regression to identify factors associated with recent HIV infection and to identify subpopulations with high proportions of recent HIV infections.ResultsApproximately 10,257 newly diagnosed cases were tested for recency using the BED-CEIA. In total, 3084 (30.4%) of those were recently infected with HIV. The highest proportion of recent HIV infections was found among men who had sex with men (MSM) (35%) and persons between 18 and 25 years of age (43.0%). Logistic regression revealed that female German intravenous drug users with a recent HIV infection had a higher chance of being detected than German MSM (OR 2.27).ConclusionsSurveillance of recent HIV infection is a useful additional tool to monitor the HIV epidemic in Germany. We could observe ongoing HIV transmission in Germany in general and in different subgroups, and we could identify factors associated with recent HIV infection in Germany.

Estimation on the HIV-1 incidence in Liangshan Yi Autonomous Prefecture, under BED-capture enzyme immunoassay, from 2011 to 2013

This paper aimed to analyze the situation of HIV infection in Liangshan Yi Autonomous, including HIV recent rate of infection and the ongoing strategies on prevention of the disease in this prefecture. Surveillance data on population size, medical institutions, from 2011 to 2013 in Liangshan prefecture was collected. The total numbers of people living in the areas appeared as 412 608, 393 699 and 443 025 from the above mentioned three years. The overall numbers of people living with HIV/AIDS were 4 480, 3 999 and 4 719 respectively in the three years of observation, using the ELISA and WB blot. We also used the ELISA, and Western blotting methods to find out the HIV-positive individuals. We then applied the ' BED HIV-1 incidence capture enzyme immunoassay (BED-CEIA)' on these HIV-positive individuals to locate those who were recently infected, to estimate the annual recent infection rates. The HIV-positive rates in Liangshan Prefecture appeared as 1.09%, 1.02% and 1.07% respectively, from 2011 to 2013, with the recent infection rates as 0.34% (95%CI: 0.32-0.37), 0.62% (95%CI: 0.58-0.66) and 0.61% (95%CI: 0.57-0.65) respectively. The newly infections mainly involved with males, with Yi ethnicity, married, being illiterate or received primary school education. In males, the rates of infection appeared as 64.24% (433/674), 59.22% (504/851) and 58.37% (495/848) respectively, in the three years of observation among people with Yi ethnicity, the recent infection rates were 84.72% (571/674) in 2011, 94.59% (805/851) in 2012 and 84.20% (714/848) in 2013. The rates seen in married people were 61.57% (415/674), 61.45% (523/851) and 60.50% (513/848) respectively. Among the illiterates or people only received primary school education, the rates appeared as 60.24% (406/674) in 2011, 61.57% (524/851) in 2012, and 60.03% (509/848) in 2013. Using the HIV recent infection rate to describe the situation of AIDS in Liangshan prefecture, figures seemed to be more reliable than under the regular HIV-positive rate.

Incident and long-term HIV-1 infection among pregnant women in Brazil: Transmitted drug resistance and mother-to-child transmission.

Primary infection, seroconversion, and transmitted drug resistance (TDR) during pregnancy may influence the risk of mother-to-child-transmission (MTCT) of HIV-1 infection. This study estimated recent seroconversion, TDR rates, HIV-1 subtypes and pregnancy outcomes among 95 recently diagnosed, antiretroviral (ARV)-naïve pregnant women recruited during antenatal care in central western Brazil. Recent seroconversion was defined by BED-capture enzyme immunoassay (<155 days) and ambiguous nucleotides base calls (<1 year) in pol sequences (protease-PR and reverse transcriptase-RT regions). TDR was evaluated by the Calibrated Population Resistance tool. HIV-1 subtypes were defined by REGA and phylogenetic analyses. The median age of participants was 25 years; the median gestational age at diagnosis was 20.5 weeks. Based on serology and sequence polymorphism, recent infection was identified in 11.6% (11/95) and, 9 of them (82%), probably seroconverted during pregnancy; one MTCT case was observed among them. Three cases of stillbirth were observed among chronic infected patients (3.6%; 3/84). Moderate rate of TDR was observed (9/90, 10%, CI95% 4.7-18.1%). Subtype B was 60% (54/90), 13.3% (12/90) was subtype C, 6.7% (6/90) was subtype F1. Recombinant B(PR) /F1(RT) and F1(PR) /B(RT) viruses comprised 15.5% (14/90); B(PR) /C(RT) mosaics represented 4.4% (4/90). Seroconversion during pregnancy, late presentation to antenatal care and moderate TDR identified in this study represent significant challenges for the MTCT elimination. J. Med. Virol. 88:1936-1943, 2016. © 2016 Wiley Periodicals, Inc.

HIV-1 incidence among people seeking voluntary counseling and testing centers, including pregnant women, in Pernambuco State, Northeast Brazil.

The HIV-1 epidemic in Brazil has displayed new characteristics over time, with an increase in heterosexual transmission and a decline in the male-to-female ratio in AIDS cases. HIV screening was offered to patients attending the Voluntary Counseling and Testing Center in Paulista, Greater Metropolitan Recife, Pernambuco State, in Northeast Brazil, to determine HIV-1 incidence. BED capture enzyme immunoassay (BED-CEIA) was used to measure HIV-1 incidence, comparing it to the AxSYM avidity index method (Ax-AI). From 2006 to 2009, 14,014 individuals were tested, and only 18 pregnant women were diagnosed with HIV infection, resulting in 0.15% annual incidence (95%CI: 0-0.33), significantly lower than in men (1.03; 95%CI: 0.45-1.61) and non-pregnant women (0.50; 95%CI: 0.11-0.89). Despite the low HIV-1 incidence in pregnant women, the high rate of recent infection detected during prenatal care emphasizes the need to increase measures to prevent vertical transmission.

Genetic diversity of HIV-1 and transmitted drug resistance among newly diagnosed individuals with HIV infection in Hangzhou, China.

HIV transmitted drug resistance (TDR) can compromise antiretroviral therapy (ART) in resource-limited countries like China where ART has been scaled up and thus leads to an important public health concern. The aim of the study was to elucidate the HIV-1 genetic characteristics and TDR in Hangzhou, China. Two-hundred eleven ART-naive, newly diagnosed individuals were enrolled during January and August 2013. Specimens were classified as recent or chronic infections using the BED capture enzyme immunoassay (BED-CEIA). The pol fragment covering the entire protease and the first 300 codons of the reverse transcriptase gene was amplified by RT-PCR and nested PCR. Genotypic drug resistance (DR) and phylogenetic analysis were performed on the 200 obtained sequences. Multiple genotypes were identified, including CRF01_AE (62.0%), CRF07_BC (31.0%), subtype B (2.0%), CRF08_BC (1.5%), CRF55_01B (1.0%), CRF18_cpx (0.5%), and unique recombinant forms (URFs, 2.0%). All the four URFs were found in men who have sex with men, consisting of a recombination of CRF01_AE with subtype B or CRF07_BC. The prevalence of primary DR in newly diagnosed individuals in Hangzhou was low (4.0%). The proportion of DR mutation to protease inhibitors (PIs), nucleoside reverse transcriptase inhibitors (NRTIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs) was 1.5%, 1.5%, and 1.0%, respectively. BED-CEIA revealed that 21.8% (45/211) of the specimens were associated with recent infections. The prevalence of TDR in recent infections was moderate (6.5%). High HIV diversity and relatively high prevalence of TDR in new infections has been found in Hangzhou, indicating an increasing challenge for future HIV prevention and treatment.

The changing trends of HIV-1 prevalence and incidence from sentinel surveillance of five sub-populations in Yunnan, China, 2001-2010.

BackgroundYunnan is one of the provinces hardest-hit by HIV in China. To understand HIV epidemic dynamics and evaluate prevention effectiveness, we studied the changing trends in HIV-1 prevalence and incidence among five sub-populations in Yunnan.MethodsConsecutive sentinel surveillances were conducted among people who inject drugs (PWID), male sexually transmitted diseases (STD) clinic attendees, and pregnant women for 2001–2010,female sex workers (FSWs) for 2007–2010, men who have sex with men (MSM) for 2008–2010. For the newly diagnosed HIV-seropositive samples, the recent infections were determined with BED-capture enzyme immunoassay (BED-CEIA), based on which HIV incidence was calculated for each sub-population using McDougal algorithm.ResultsFrom 231,117 individuals, 6,107 HIV-positive samples were tested with BED-CEIA, among which 964 samples were identified as recent infections. In PWID, HIV prevalence for 2001–2010 was between 27.16% and 18.35%, while the estimated incidence rate significantly decreased from 11.68% in 2001 to 1.70% in 2010. Among male STD clinic attendees, both the HIV prevalence (from 3.62% in 2001 to 1.73% in 2010) and incidence (from 1.10% in 2001 to 0.40% in 2010) showed a significant decreasing trend. In FSWs, the HIV prevalence for 2007–2010 kept stable (between 2.46% and 1.95%), while the HIV incidence significantly decreased (from 0.71% in 2007 to 0.31% in 2010). In MSM, the HIV prevalence (between 11.78% and 9.42%) and incidence (between 6.01% and 8.38%) remained stable at a relatively high level for 2008–2010. In pregnant women, the HIV prevalence (between 0.44% and 0.30%) and incidence (between 0.15% and 0.08%) remained stable for 2001–2010.ConclusionThe HIV incidences in PWID, male STD clinic attendees and FSWs showed the decreasing trend, supporting a positive effect of prevention strategies for these sub-populations. MSM with the highest HIV incidence have become the sub-population most at risk. In most sub-populations, the HIV prevalence did not decline, suggesting the disease burden is still heavy. These findings are valuable for developing HIV prevention strategies in Yunnan.

Antibody Maturation in Women Who Acquire HIV Infection While Using Antiretroviral Preexposure Prophylaxis.

The CAPRISA 004 preexposure prophylaxis (PrEP) randomized trial demonstrated that women who used a vaginal gel containing the antiretroviral drug tenofovir (TFV) had a 39% lower risk of acquiring human immunodeficiency virus (HIV). It is not known whether topical TFV alters the antibody response to breakthrough HIV infection. In this study, antibody maturation was evaluated using 3 serologic assays: the BED capture enzyme immunoassay (CEIA), the Bio-Plex (Luminex) assay, and the Bio-Rad avidity assay. Tests were performed using serum samples collected 3, 6, 9, 12, 24, 36, 48, and >48 months after seroconversion from 95 women in the CAPRISA 004 trial (35 in the TFV gel arm and 60 in the placebo arm). For the BED CEIA and Luminex assay, linear mixed effects models were used to examine test results by study arm. Cox proportional hazard analysis was used to examine time to avidity cutoff. Anti-HIV antibody titers did not differ between study arms. Women assigned to TFV gel demonstrated slower antibody avidity maturation, as determined by the Bio-Rad (P = .04) and gp120 Bio-Plex (P = .028) assays. Women who were assigned to receive topical TFV but became infected had slower antibody avidity maturation, with potential implications for diagnosis and antibody-based incidence assays as access to antiretroviral therapy-based PrEP is increased.

HIV-1 subtype diversity and transmission clusters among men having sex with men who recently got HIV-l infection, in Zhejiang province

To understand the HIV-1 subtype diversity and transmission characteristics in men having sex with men (MSM) in Zhejiang province. A total of 233 newly diagnosed as HIV-1 positive patients in 2011 were screened out by BED capture enzyme immunoassay (BED-CEIA). Among them, 107 eligible subjects were enrolled for further molecular epidemiological study. Viral RNA was extracted from plasma samples and followed by reverse transcription PCR and nested PCR for amplification of pol gene fragments, sequencing, and bioinformatics analysis. There were no statistically significant differences regarding the social demographic distribution between the subjects under study and those recently infected MSM population. The rate of success for sequence acquisition was 94.4% (101/107). The highest proportion of subtype was CRF01_AE (62.4%), followed by CRF07_BC (31.7%) and with three cases of subtype B, one case of CRF55_01B and two cases of unique recombinant form (CRF01_AE/B and CRF01_AE/CRF07_BC). The phylogenetic trees were mainly divided into CRF01_AE cluster 1, cluster 2 and CRF07_BC cluster 3. The strains located in Hangzhou were diffused in the branches of phylogenetic tree. 10 transmission clusters were found, in which 80% involved two or more regions and 90% was associated with patients residing in Hangzhou. Three surveillance drug resistance mutations (M46I, T215S and G190A) were found in three samples (each sample harbored only one resistance mutation). The overall rate of transmitted drug resistance (TDR) was 2.97%. The increasing complexity of HIV was noticed in MSM in Zhejiang province. However, the prevalence of TDR was low. Cross-regional HIV transmission in MSM was common, which inferred from the study. Hangzhou might play a central regional role in the intra-provincial spread of HIV, to form an interwoven complex network in the MSM population.

The Recency Period for Estimation of Human Immunodeficiency Virus Incidence by the AxSYM Avidity Assay and BED-Capture Enzyme Immunoassay in the Republic of Korea

ObjectivesMeasurement of the incidence of the human immunodeficiency virus (HIV) is very important for epidemiological studies. Here, we determined the recency period with the AxSYM avidity assay and the BED-capture enzyme immunoassay (BED-CEIA) in Korean seroconverters. MethodsTwo hundred longitudinal specimens from 81 seroconverters with incident HIV infections that had been collected at the Korea National Institute of Health were subjected to the AxSYM avidity assay (cutoff = 0.8) and BED-CEIA (cutoff = 0.8). The statistical method used to estimate the recency period in recent HIV infections was nonparametric survival analyses. Sensitivity and specificity were calculated for 10-day increments from 120 days to 230 days to determine the recency period. ResultsThe mean recency period of the avidity assay and BED-CEIA using a survival method was 158 days [95% confidence interval (CI), 135–181 days] and 189 days (95% CI, 170–208 days), respectively. Based on the use of sensitivity and specificity, the mean recency period for the avidity assay and BED-CEIA was 150 days and 200 days, respectively. ConclusionWe determined the recency period to estimate HIV incidence in Korea. These data showed that the nonparametric survival analysis often led to shorter recency periods than analysis of sensitivity and specificity as a new method. These findings suggest that more data from seroconverters and other methodologies are needed to determine the recency period for estimating HIV incidence.

Assessment of ambiguous base calls in HIV-1 pol population sequences as a biomarker for identification of recent infections in HIV-1 incidence studies.

An increase in the proportion of ambiguous base calls in HIV-1 pol population sequences during the course of infection has been demonstrated in different study populations, and sequence ambiguity thresholds to classify infections as recent or nonrecent have been suggested. The aim of our study was to evaluate sequence ambiguities as a candidate biomarker for use in an HIV-1 incidence assay using samples from antiretroviral treatment-naive seroconverters with known durations of infection (German HIV-1 Seroconverter Study). We used 2,203 HIV-1 pol population sequences derived from 1,334 seroconverters to assess the sequence ambiguity method (SAM). We then compared the serological incidence BED capture enzyme immunoassay (BED-CEIA) with the SAM for a subset of 723 samples from 495 seroconverters and evaluated a multianalyte algorithm that includes BED-CEIA results, SAM results, viral loads, and CD4 cell counts for 453 samples from 325 seroconverters. We observed a significant increase in the proportion of sequence ambiguities with the duration of infection. A sequence ambiguity threshold of 0.5% best identified recent infections with 76.7% accuracy. The mean duration of recency was determined to be 208 (95% confidence interval, 196 to 221) days. In the subset analysis, BED-CEIA achieved a significantly higher accuracy than the SAM (84.6 versus 75.5%, P < 0.001) and results were concordant for 64.2% (464/723) of the samples. Also, the multianalyte algorithm did not show better accuracy than the BED-CEIA (83.4 versus 84.3%, P = 0.786). In conclusion, the SAM and the multianalyte algorithm including SAM were inferior to the BED-CEIA, and the proportion of sequence ambiguities is therefore not a preferable biomarker for HIV-1 incidence testing.

Screening for acute HIV infections and estimating HIV incidence among female sex workers from low-grade venues in Guangxi, China.

BackgroundGuangxi has become one of the provinces with the most severe HIV-1 epidemic in China, where heterosexual contact is the dominant transmission route. However, data of acute HIV infections and HIV incidence among female sex workers (FSWs) from low-grade venues are scant.MethodsA cross-sectional survey was performed among FSWs from low-grade venues in Guangxi. HIV antibody screening was performed by rapid testing (RT). HIV antibody–negative specimens were screened by pooled nucleic acid amplification testing (NAAT) for acute HIV infections. HIV antibody-positive specimens were further analyzed by Western blot (WB), followed by an HIV-1 BED capture enzyme immunoassay (BED-CEIA) to identify the recent infections. HIV-1 incidence was estimated by the data of pooled NAAT and BED-CEIA, respectively.ResultsA total of 7936 FSWs were recruited and answered the questionnaires. We successfully collected the blood samples from 6469 (81.5%) participants, of which 139 (2.1%) were HIV antibody–positive and 6330 (97.9%) were HIV antibody-negative by RT. With pooled NAAT, 7 cases were found to be HIV RNA positive, representing an additional 5.0% of HIV-infected persons and an estimated HIV incidence of 1.45 (95% CI: 1.17–1.76) per 100 person years. There were 137 positive and 2 indeterminate by WB, of which 124 (90.5%) positive specimens were subjected to BED-CEIA testing identifying 28 recent infections. The HIV incidence determined by BED-CEIA testing was 1.04 (95% CI: 0.65–1.43) per 100 person years. The overall prevalence of HIV among FSWs from low-grade venues in Guangxi was 2.2% (95% CI: 1.9–2.6).ConclusionsWe found that the addition of HIV RNA screening to routine HIV antibody testing significantly improved the detection of HIV infection among FSWs from low-grade venues in Guangxi. Our findings also provided the useful baseline data of HIV incidence among this population for targeting local HIV prevention, intervention, monitoring and treatment.

HIV infection and syphilis among men who have sex with men in Beijing: a survey in 2012

Objective To determine the prevalence of and correlations between HIV infection and syphilis among men who have sex with men (MSM) in Beijing.Methods Totally,600 MSM collected from sentinel surveillance sites for AIDS in Beijing were recruited in this study,and underwent screening tests for HIV infection and syphilis.Enzyme-linked immunosorbent assay (ELISA) was used for the primary screening for HIV infection,and Western blot for its confirmation.Both nontreponemal test (rapid plasma regain (RPR) assay) and treponemal test (Treponema pallidum particle agglutination assay,TPPA) were performed to detect syphilis,and only those with a reactive TPPA result were defined as having syphilis (including past infection).Specimens confirmed as HIV-1 positive were further tested with BED-capture enzyme immunoassay (CEIA) to find recent HIV-1 infection,and the incidence of HIV infection was then calculated.The correlation between syphilis and HIV infection was statistically analyzed.Results Of the 600 MSM,49 (8.17％) had HIV infection,including 14 cases of recent infection,with the incidence rate of HIV infection being 4.68％; 51 were positive for both RPR and TPPA tests with the infection rate (including past infection) being 18.5％ (111/600).People without a Beijing household registration and those with high education levels accounted for a large proportion of HIV-infected MSM.Conclusions The prevalence and incidence of HIV infection as well as prevalence of syphilis maintain at a relatively high level in MSM in Beijing.HIV infection is markedly correlated with syphilis in MSM population. Key words: Homosexuality, male; HIV infections; Syphilis

Comparison among the BED capture enzyme immunoassay test and AxSYM avidity index assay for determining recent HIV infection and incidence in two Voluntary Counselling and Testing Centres in Northeast Brazil

The aims of this study were to compare the automated AxSYM avidity assay index with the BED capture enzyme immunoassay test and to calculate the HIV-1 incidence using the BED capture enzyme immunoassay and AxSYM avidity assay index algorithms within a population seeking the Voluntary Counselling and Testing Centres in two municipalities in the Metropolitan Region of Recife, Northeast of Brazil. An analysis was conducted in 365 samples that tested positive for HIV infection from frozen serum collected during the period 2006–2009. There was a similar proportion of males and females; most patients were heterosexual (86%) with a median age of 29 years. Of the 365 samples, 102 (28%) and 66 (18.1%) were identified as recent infections by BED capture enzyme immunoassay and AxSYM avidity assay index, respectively. The HIV-1 total incidence in the BED capture enzyme immunoassay and AxSYM avidity assay index algorithms were: 0.79 (95% CI: 0.60–0.98) and 0.34 (95% CI: −0.04 to 0.72), respectively. Incidence was higher among men. There was good agreement between the tests, with a kappa of 0.654 and a specificity of 95.8%. AxSYM avidity assay index may be helpful in improving the quality of the estimates of recent HIV infection and incidence, particularly when used in a combined algorithm with BED capture enzyme immunoassay.

Immune Responses in Ugandan Women Infected With Subtypes A and D HIV Using the BED Capture Immunoassay and an Antibody Avidity Assay

Analysis of samples from Uganda using serologic HIV incidence assays reveal that individuals with subtype D infection often have weak humoral immune responses to HIV infection. It is unclear whether this reflects a poor initial response to infection or a waning antibody response later in infection. Samples (N = 2614) were obtained from 114 women aged 18-45 years in the Ugandan Genital Shedding and Disease Progression Study cohort (2001-2009; 82 subtype A, 32 subtype D; median 23 samples/women, range 3-41 samples, median follow-up of 6.6 years). Samples were analyzed using the BED capture immunoassay (cutoff, 0.8 OD-n) and the avidity assay (cutoff, 90% Avidity Index). Antibody maturation was assessed by having the BED capture enzyme immunoassay (BED-CEIA) or avidity value exceed the assay cutoff 1 or 2 years after infection. The waning antibody response was measured by having the BED-CEIA or avidity value fall >20% below the maximum value. For the BED-CEIA, 8 women with subtype A infection and 3 women with subtype D infection never progressed previously the cutoff value (median, 5.9 years follow-up after infection). Six women with subtype D infection never achieved an avidity index >90%. Subtype did not impact the proportion of women whose assay values regressed by >20% of the maximal value (for BED-CEIA: 33% for A, 41% for D, P = 0.51; for avidity: 1% for A, 6% for D, P = 0.19). The higher frequency of misclassification of individuals with long-term subtype D infection as recently infected using serologic incidence assays reflects a weak initial antibody response to HIV infection that is sustained over time.

Changing the Landscape of the HIV Epidemic among MSM in China: Results from Three Consecutive Respondent-Driven Sampling Surveys from 2009 to 2011

This study assessed the changes of HIV incidence and its predictors among Beijing's men who have sex with men (MSM). Three consecutive cross-sectional surveys were carried out using a consistent respondent-driven sampling (RDS) approach in 2009, 2010, and 2011, respectively. Structured-questionnaire based interviews were completed with computer-assisted self-administration. Incident infection was examined with BED capture enzyme immunoassay (BED-CEIA). The overall rate of HIV prevalence was 8.0% in the three years (95% confidence interval [CI]: 4.9%–11.2%). The overall rate of BED-CEIA incidence was 7.8/100 person years (PY) (95% CI: 5.5–10.1) with 6.8/100PY (95% CI: 3.4–10.2) in 2009, 11.2/100PY (95% CI: 6.2–16.3) in 2010, and 5.8/100PY (95% CI: 2.4–9.3) in 2011, respectively. Multivariable logistic regression analysis revealed that, compared with HIV-negative MSM, recently infected MSM were more likely to be bisexual (adjusted odds ratio [AOR] = 2.1, 95% CI: 1.1–4.1), live in Beijing ≤3 years (AOR = 2.1, 95% CI: 1.2–4.0), and have a negative attitude towards safe sex (AOR = 1.1 per scale point, 95% CI: 1.0–1.1). This study demonstrated a disturbing rise of HIV infections among Beijing's MSM. These findings underscored the urgency of scaling up effective and better-targeted intervention services to stop the rapid spread of the virus.