Assessment of an instrument scale measuring the knowledge of antiretroviral therapy among people living with HIV.

BACKGROUND: Antiretroviral therapy (ART) is currently the most effective way to treat people living with human immunodeficiency virus (PLHs) and reduce HIV transmission. While there are many factors that reduce adherence to ART, PLHs' knowledge about ART may determine the level of adherence. It is necessary to design and assess an instrument scale that measures the knowledge of antiretroviral therapy among PLHs. METHOD: A cross-sectional study was conducted among PLHs in Honghe Hani and Yi Autonomous Prefecture, China. Both exploratory and confirmatory factor analyses were used to examine the latent factors of antiretroviral therapy knowledge scale. Internal consistency was assessed separately for the scale and its dimensions by estimating Cronbach's alphas, split-half reliability and Spearman's correlation coefficient. ANOVAs were used to compare the scores of different dimensions with sociodemographic characteristics. RESULTS: Four factors were extracted according to factor loadings. They had high internal consistency reliability (Cronbach's alpha: 0.70-0.95) and good construct validity (standardized factor loading range: 0.46-0.86) in the scale. Goodness of fit indices indicated that a four-factor solution fit the data at an accepted level (χ2/degree ratio = 1.980, RMSEA = 0.069, GFI = 0.909, CFI = 0.957, NFI = 0.917, TLI = 0.944). ANOVAs indicated that the score was higher among PLHs who were Han, had spouses/partners, were non-famers or migrant workers, initiated ART, and had a high school or above education. CONCLUSION: The psychometric assessment indicated that this ART knowledge scale had accepted internal consistency and discriminant construct validity. It can be used to assess the knowledge of antiretroviral therapy for PLHs.

Travel time prediction of urban public transportation based on detection of single routes.

Improving travel time prediction for public transit effectively enhances service reliability, optimizes travel structure, and alleviates traffic problems. Its greater time-variance and uncertainty make predictions for short travel times (≤35min) more subject to be influenced by random factors. It requires higher precision and is more complicated than long-term predictions. Effectively extracting and mining real-time, accurate, reliable, and low-cost multi-source data such as GPS, AFC, and IC can provide data support for travel time prediction. Kalman filter model has high accuracy in one-step prediction and can be used to calculate a large amount of data. This paper adopts the Kalman filter as a travel time prediction model for a single bus based on single-line detection: including the travel time prediction model of route (RTM) and the stop dwell time prediction model (DTM); the evaluation criteria and indexes of the models are given. The error analysis of the prediction results is carried out based on AVL data by case study. Results show that under the precondition of multi-source data, the public transportation prediction model can meet the accuracy requirement for travel time prediction and the prediction effect of the whole route is superior to that of the route segment between stops.

Assessment of two-pool multiplex long-amplicon nanopore sequencing of SARS-CoV-2.

Genomic surveillance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) plays an important role in COVID-19 pandemic control and elimination efforts, especially by elucidating its global transmission network and illustrating its viral evolution. The deployment of multiplex PCR assays that target SARS-CoV-2 followed by either massively parallel or nanopore sequencing is a widely-used strategy to obtain genome sequences from primary samples. However, multiplex PCR-based sequencing carries an inherent bias of sequencing depth among different amplicons, which may cause uneven coverage. Here we developed a two-pool, long-amplicon 36-plex PCR primer panel with ~1000-bp amplicon lengths for full-genome sequencing of SARS-CoV-2. We validated the panel by assessing nasopharyngeal swab samples with a <30 quantitative reverse transcription PCR cycle threshold value and found that ≥90% of viral genomes could be covered with high sequencing depths (≥20% mean depth). In comparison, the widely-used ARTIC panel yielded 79%-88% high-depth genome regions. We estimated that ~5 Mbp nanopore sequencing data may ensure a >95% viral genome coverage with a ≥10-fold depth and may generate reliable genomes at consensus sequence levels. Nanopore sequencing yielded false-positive variations with frequencies of supporting reads <0.8, and the sequencing errors mostly occurred on the 5' or 3' ends of reads. Thus, nanopore sequencing could not elucidate intra-host viral diversity.

Measuring HIV stigma at the family level: psychometric assessment of the Chinese Courtesy Stigma Scales (CCSSs).

Courtesy stigma is the stigmatization a person perceives or experiences due to their association with a stigmatized individual or group. Most HIV-related stigma scales have been developed for people living with HIV/AIDS (PLWHAs), but not for their HIV-uninfected family members. To date, few measurement scales have been designed to measure the degree of stigma among both PLWHAs and their HIV-uninfected family members at the family level. We developed a set of courtesy stigma scales and estimated their reliability and validity from 256 PLWHAs and 256 of their HIV-uninfected family members. Exploratory and confirmatory factor analyses were performed in two independent samples: a development sample (N = 216) and a validation sample (N = 296), respectively. Two factors ("public stigma" and "self-perceived stigma") had high internal consistency reliability (Cronbach's alpha coefficient between 0.83-0.90) and good construct validity (standardized factor loading range: 0.37-0.95) in both samples. These findings document that the newly developed brief instrument is a psychometrically sound measure of HIV-related stigma among both PLWHAs and their HIV-uninfected family members.

Residential segregation and gonorrhea rates in US metropolitan statistical areas, 2005-2009.

BACKGROUND: The residential segregation of black populations, often in areas of high-economic disadvantage and low social status, may play a crucial role in the observed racial inequities in sexually transmitted disease rates. METHODS: An ecological analysis of 2005 to 2009 average gonorrhea rates was performed across 277 US metropolitan statistical areas (MSAs). The black isolation index and Gini index of income inequality were used as proxy measures for racial and economic residential segregation respectively, derived from 2005 to 2009 US Census estimates. We used logistic regression modeling to produce estimates of odds ratios (ORs) and 95% confidence intervals (CIs) for the association between the segregation indices, both independently and in combination, on gonorrhea rates in MSAs. Effect measure modification was assessed by calculating the relative excess risk due to interaction between the 2 indices. RESULTS: Compared with MSAs with low levels of racial segregation, MSAs with high levels of racial segregation had increased odds of high gonorrhea rates (adjusted OR, 3.37; 95% CI, 1.23-9.21). Similarly, higher levels of income inequality predicted higher gonorrhea rates, although this association did not persist after adjustment for potential confounders (adjusted OR, 1.54; 95% CI, 0.74-3.24). In combined models, the influence of racial residential segregation on gonorrhea rates was stronger than that of income inequality-based segregation; there was no evidence of additivity or a multiplicative interaction. CONCLUSIONS: Residential segregation by race or income equality may be a key component in the perpetuation of high rates of gonorrhea and other sexually transmitted diseases among black populations in the United States.

Psychometric assessment of scales measuring HIV public stigma, drug-use public stigma and fear of HIV infection among young adolescents and their parents.

The objective of this study was to design and assess measurement instruments that accurately measure the levels of stigma among individuals with a primarily collectivist culture. A cross-sectional study was conducted among middle school students and their parents or guardians in a rural area of China. Exploratory and confirmatory factor analyses were used to examine and determine the latent factors of the sub-scales of stigma respectively, among students and their parents. Factor analyses identified three sub-scales: HIV public stigma (seven items), drug-use public stigma (nine items), and fear of HIV infection (seven items). There were no items with cross-loading onto multiple factors, supporting the distinctness of the constructs that these scales were meant to measure. Goodness of fit indices indicated that a three-factor solution fit, the data at an acceptable level in the student sample (χ(2) /degree ratio=1.98, comparative fit index [CFI]=0.92, root mean square error of approximation [RMSEA]=0.055, standardized root mean square residual [SRMR]=0.057) and in the parent sample (χ(2)/degree ratio=1.95, CFI=0.91, RMSEA=0.06, SRMR=0.059). Reliability of the three scales was excellent (Cronbach's alpha: 0.78-0.92 for students; 0.80-0.94 for parents or guardians) and stable across split samples and for the data as a whole. The scales are brief and suitable for use in developing countries where the collectivist culture prevails.

Assessment of Random Recruitment Assumption in Respondent-Driven Sampling in Egocentric Network Data.

BACKGROUND: One of the key assumptions in respondent-driven sampling (RDS) analysis, called "random selection assumption," is that respondents randomly recruit their peers from their personal networks. The objective of this study was to verify this assumption in the empirical data of egocentric networks. METHODS: We conducted an egocentric network study among young drug users in China, in which RDS was used to recruit this hard-to-reach population. If the random recruitment assumption holds, the RDS-estimated population proportions should be similar to the actual population proportions. Following this logic, we first calculated the population proportions of five visible variables (gender, age, education, marital status, and drug use mode) among the total drug-use alters from which the RDS sample was drawn, and then estimated the RDS-adjusted population proportions and their 95% confidence intervals in the RDS sample. Theoretically, if the random recruitment assumption holds, the 95% confidence intervals estimated in the RDS sample should include the population proportions calculated in the total drug-use alters. RESULTS: The evaluation of the RDS sample indicated its success in reaching the convergence of RDS compositions and including a broad cross-section of the hidden population. Findings demonstrate that the random selection assumption holds for three group traits, but not for two others. Specifically, egos randomly recruited subjects in different age groups, marital status, or drug use modes from their network alters, but not in gender and education levels. CONCLUSIONS: This study demonstrates the occurrence of non-random recruitment, indicating that the recruitment of subjects in this RDS study was not completely at random. Future studies are needed to assess the extent to which the population proportion estimates can be biased when the violation of the assumption occurs in some group traits in RDS samples.

Psychometric assessment of HIV/STI sexual risk scale among MSM: a Rasch model approach.

BACKGROUND: Little research has assessed the degree of severity and ordering of different types of sexual behaviors for HIV/STI infection in a measurement scale. The purpose of this study was to apply the Rasch model on psychometric assessment of an HIV/STI sexual risk scale among men who have sex with men (MSM). METHODS: A cross-sectional study using respondent driven sampling was conducted among 351 MSM in Shenzhen, China. The Rasch model was used to examine the psychometric properties of an HIV/STI sexual risk scale including nine types of sexual behaviors. RESULTS: The Rasch analysis of the nine items met the unidimensionality and local independence assumption. Although the person reliability was low at 0.35, the item reliability was high at 0.99. The fit statistics provided acceptable infit and outfit values. Item difficulty invariance analysis showed that the item estimates of the risk behavior items were invariant (within error). CONCLUSIONS: The findings suggest that the Rasch model can be utilized for measuring the level of sexual risk for HIV/STI infection as a single latent construct and for establishing the relative degree of severity of each type of sexual behavior in HIV/STI transmission and acquisition among MSM. The measurement scale provides a useful measurement tool to inform, design and evaluate behavioral interventions for HIV/STI infection among MSM.

Egocentric networks of Chinese men who have sex with men: network components, condom use norms, and safer sex.

Research on risk behaviors among men who have sex with men (MSM) is often based on individualistic models of health behavior, but sexual behavior is inherently social in nature and often determined by constituents of social networks. The objective of this study was to examine relationships among social networks, network norms of condom use, and safer sex. A respondent-driven sampling study recruited 350 MSM in the Shenzhen region of China between November and December 2007 and collected information on network components (relations, structures, and functions) and HIV risk behavior among egos (those interviewed) and their network alters. A total of 2385 alters were nominated by the 350 egos. Egos reported an average of 4 nonsexual relation alters and 2 sexual-partner alters. Egos perceived receiving more tangible and emotional support from nonsexual relation alters than from sexual-partner alters. Two thirds (69%) of egos consistently used condoms. Sixty-seven percent of egos reported having 1 or more alters who always encouraged egos to use condoms, 84% had 1 or more alters who consistently used condoms, and 55% had 1 or more alters who insisted on condom use. Both subjective and descriptive norms were positively associated with consistent condom use. Network components were associated with the levels of the two norms. These findings suggest that social network components may activate or strengthen condom use norms within networks, which, in turn, determine consistent condom use among MSM. HIV behavioral interventions need to target the promotion of safer sex practices through enhancing peer norms of condom use within networks.

Longitudinal predictability of sexual perceptions on subsequent behavioural intentions among Bahamian preadolescents.

OBJECTIVES: To assess the relationship of baseline behavioural intentions and sexual perceptions with subsequent intentions regarding sexual initiation and condom use in Bahamian preadolescents. METHOD: Longitudinal data were obtained at baseline and 8 months later from 424 sexually inexperienced Bahamian youth aged 9-12 years, who served as 'controls' in a HIV risk-reduction intervention study. Sexual perceptions were measured based on a social cognitive model, protection motivation theory. RESULTS: Baseline intention to have sex was a strong predictor of follow-up intention to engage in sex for boys, but was not a predictor for girls. Baseline condom use intention was not related to subsequent intention to use condoms for either male or female youth. Perceptions of girls, compared with boys, were less endorsing of sexual initiation. Some protection motivation theory constructs regarding sexual perceptions were predictive of subsequent behavioural intentions. Among boys, low perceived self-efficacy to avoid sexual intercourse and positive feelings about having sex predicted their intention to have sex. Among girls, perceived peer sexual behaviour and a limited understanding of the adverse consequences of sexual intercourse were predictors of their subsequent intention to initiate sex. Perceived self-efficacy to use condoms and response efficacy of condom use were significant predictors of condom use intention for both boys and girls. CONCLUSIONS: These results suggest that prevention intervention efforts should target predictive perceptions and consider sex differences in sexual perceptions.

Reduction in human immunodeficiency virus risk among youth in developing countries.

OBJECTIVE: To address the 6-month efficacy of a human immunodeficiency virus (HIV) prevention intervention targeted to youth and delivered with and without a parental monitoring intervention in a developing country (the Bahamas). DESIGN: Randomized, controlled, 3-cell intervention trial with a 6-month postintervention follow-up. SETTING: Elementary schools in the Bahamas. PARTICIPANTS: A total of 1282 Bahamian sixth-grade students (and 1175 parents) in 15 schools. INTERVENTIONS: Youth and parents were randomized at the level of the school to receive the following interventions: (1) Focus on Youth in the Caribbean (FOYC) plus Caribbean Informed Parents and Children Together (CImPACT), (2) FOYC plus an attention control for parents (Goal for It [GFI]), or (3) an attention control for the youth (Wonderous Wetlands [WW]) plus the GFI. The 10-session FOYC or WW curriculum was delivered as part of the elementary school curriculum. The GFI or CImPACT was delivered to parents in the evenings or on weekends. MAIN OUTCOME MEASURES: Risk and protective knowledge, condom use skills, perceptions, interventions, and self-reported behaviors. RESULTS: Compared with the WW, the FOYC significantly increased knowledge, condom use skills, protective perceptions, and intentions to engage in safer behaviors. Among youth, no differences were found in knowledge or condom use skills based on parent intervention; among parents, those receiving the CImPACT demonstrated superior condom use skills after the intervention. CONCLUSIONS: Protective knowledge, skills, perceptions, and intentions of youth from 1 developing country can be significantly improved by youth intervention delivered through the schools. Longer follow-up is needed to determine if risk behaviors will be reduced and how long protective results will be sustained.

Cigarette smoking among rural-to-urban migrants in Beijing, China.

BACKGROUND: Tobacco use remains a substantial public health challenge in China. The rapidly growing rural-to-urban migrant population currently numbering approximately 121 million individuals may be especially vulnerable to tobacco use. METHODS: Cigarette smoking levels and associated factors were examined among 2,201 subjects using cross-sectional data from the Migrant Health Behavior Survey (MHBS), conducted in 2002, Beijing, China. RESULTS: Respondents (39.3% females) were 18-30 years old with a mean age of 22.7 years; 77.3% were single and 35.6% had at least attended high school for education. Migrants reported an average of 4 years of migratory experience; 28.8% had worked in at least three cities and 36.8 had held at least four jobs. Males (51.7%) and females (10.9%) reported 30-day cigarette use. Smoking levels were positively associated with age, education, income, migration years, number of cities in which the migrants had worked, living in rental properties, and number of jobs held. Smoking levels were negatively associated with job and life satisfaction and living with relatives in Beijing. Smoking levels were not associated with marital status. CONCLUSIONS: Female migrants had disproportionately high rate of cigarette smoking. Several conditions and experiences common to the migratory lifestyle were associated with increased levels of smoking. Tobacco control measures are needed to protect migrant populations in China.

Is syndromic management better than the current approach for treatment of STDs in China? Evaluation of the cost-effectiveness of syndromic management for male STD patients.

BACKGROUND: The syndromic treatment approach has not been evaluated in sexually transmitted disease (STD) clinics in China. GOAL: The goal was to evaluate and compare the validity and cost-effectiveness of syndromic management with current STD management for men in clinics in Hefei, China. STUDY DESIGN: Diagnostic accuracy, treatment appropriateness, costs, and effectiveness of current clinical procedures and syndromic management were compared for 406 men attending four STD clinics. RESULTS: A modified World Health Organization (WHO) syndromic algorithm for urethral discharge yielded 100% sensitivity and a 69% positive predictive value (PPV). A syndromic algorithm for genital ulcers correctly treated all syphilis patients, with a 25% PPV. The average cost (in US dollars) per correct treatment by the current approach was 323.48 dollars for urethritis and 85.65 dollars for syphilis. For the syndromic approach, the average cost per correct treatment was 3.15 dollars for urethritis and 13.54 dollars for syphilis. CONCLUSION: Syndromic management can provide better treatment for men with STDs at significantly lower cost in resource-poor settings such as China.