Validity of dried blood spot testing for sexually transmitted and blood-borne infections: A narrative systematic review.

Testing for human immunodeficiency virus (HIV) and hepatitis C virus (HCV) using dried blood spot (DBS) specimens has been an integral part of bio-behavioural surveillance in Canada for almost two decades, though less is known regarding the use of DBS in surveillance of other sexually transmitted and blood-borne infections (STBBI). A systematic review was conducted using a peer-reviewed search strategy to assess the current evidence regarding the validity of STBBI testing using DBS specimens. Eligibility criteria included studies reporting use of DBS specimens for STBBI testing with either commercially available or "in-house" tests in populations 15 years of age or older. Studies reporting a measure of validity such as sensitivity, specificity, positive and negative predictive values were eligible for inclusion. Quality of studies and risk of bias were assessed using the QUADAS-2 tool. A total of 7,132 records were identified. Of these, 174 met the criteria for inclusion. Among the studies that reported validity measures, a substantial proportion demonstrated high sensitivity (≥90%) in 62.5% of cases (N = 334/534 sensitivity measurements), and high specificity (≥90%) was observed in 84.9% of instances (N = 383/451 specificity measurements). However, the quality of the studies varied greatly. Our findings support the validity of the use of DBS specimens in STBBI testing where sufficient evidence was available, but validity is highly dependent on thorough method development and validation.

Innovations in public health surveillance: An overview of novel use of data and analytic methods.

Innovative data sources and methods for public health surveillance (PHS) have evolved rapidly over the past 10 years, suggesting the need for a closer look at the scientific maturity, feasibility, and utility of use in real-world situations. This article provides an overview of recent innovations in PHS, including data from social media, internet search engines, the Internet of Things (IoT), wastewater surveillance, participatory surveillance, artificial intelligence (AI), and nowcasting. Examples identified suggest that novel data sources and analytic methods have the potential to strengthen PHS by improving disease estimates, promoting early warning for disease outbreaks, and generating additional and/or more timely information for public health action. For example, wastewater surveillance has re-emerged as a practical tool for early detection of the coronavirus disease 2019 (COVID-19) and other pathogens, and AI is increasingly used to process large amounts of digital data. Challenges to implementing novel methods include lack of scientific maturity, limited examples of implementation in real-world public health settings, privacy and security risks, and health equity implications. Improving data governance, developing clear policies for the use of AI technologies, and public health workforce development are important next steps towards advancing the use of innovation in PHS.

Summary findings from Tracks surveys implemented by First Nations in Saskatchewan and Alberta, Canada, 2018-2020.

Background: The Public Health Agency of Canada's integrated bio-behavioural surveillance system-Tracks surveys-assesses the burden of HIV, hepatitis C and associated risks in key populations in Canada. From 2018-2020, Tracks surveys were successfully implemented by First Nations Health Services Organizations in Alberta and Saskatchewan. Methods: First Nations-led survey teams invited community members who identified as First Nations, Inuit or Métis to participate in Tracks surveys and testing for HIV, hepatitis C and syphilis. Information was collected on social determinants of health, use of prevention services, substance use, sexual behaviours and care for HIV and hepatitis C. Descriptive statistics are presented. Results: Of the 1,828 survey participants, 97.4% self-identified as First Nations and 91.4% lived in an on-reserve community. Over half (52.2%) were cisgender female, average age was 36.3 years, 82.5% lived in stable housing, 82% had access to primary healthcare and 73.8% reported having good to excellent mental health. Most participants (97%) had a family member who had experienced residential school. High proportions experienced stigma and discrimination (65.6%), financial strain (64.3%) and abuse in childhood (65.1%). Testing for HIV (62.8%) and hepatitis C (55.3%) was relatively high. Prevalence of HIV was 1.6% (of whom 64% knew their infection status). Hepatitis C ribonucleic acid prevalence was 5% (44.9% of whom knew their current infection status). Conclusion: Historical and ongoing experiences of trauma, and higher prevalence of hepatitis C were identified, reaffirming evidence of the ongoing legacies of colonialism, Indian Residential Schools and systemic racism. High participation in sexually transmitted blood-borne infection testing and prevention reflect the importance of First Nations-led culturally sensitive, safe and responsive healthcare services and programs to effect improved outcomes for First Nations peoples.

Measures of HIV Pre-exposure Prophylaxis Uptake Among Gay, Bisexual, and Other Men Who Have Sex with Men in Canada and Demographic Disparities Among Those at Elevated Likelihood for HIV Acquisition.

HIV pre-exposure prophylaxis (PrEP) is an effective prevention tool being scaled up in Canada. We describe PrEP uptake and identify demographic correlates of uptake among gay, bisexual, and other men who have sex with men (gbMSM) at elevated HIV risk using data from an online survey of gbMSM residing in Canada between Oct 2017 and Jan 2018. Among the 969 participants at elevated HIV risk who had recently tested for HIV, 96.0%, 83.3%, 72.6%, and 39.7% reported awareness, knowledge, acceptability, and pursuit of PrEP, respectively; 27.1% had ever and 24.6% were currently taking PrEP. The strongest correlate of PrEP uptake was living in a city of ≥ 500,000 inhabitants; others included being out to all or almost all family, friends, and colleagues regarding sexual attraction to men, greater financial coping, and being 30-49 years of age. Improved upscaling of PrEP in Canada may be accomplished through consideration of these disparities.

Findings among Indigenous participants of the Tracks survey of people who inject drugs in Canada, Phase 4, 2017-2019.

BACKGROUND: The Tracks survey of people who inject drugs (PWID) collected data in 14 sentinel sites across Canada (2017-2019). These findings describe the prevalence of human immunodeficiency virus (HIV), hepatitis C and associated risk behaviours among Indigenous participants. METHODS: Information regarding socio-demographics, social determinants of health, use of prevention services and testing, drug use, risk behaviours, and HIV and hepatitis C testing, care and treatment was collected through interviewer-administered questionnaires. Biological samples were tested for HIV, hepatitis C antibodies and hepatitis C ribonucleic acid (RNA). Descriptive statistics were calculated and reviewed by an Indigenous-led advisory group using the Two-Eyed Seeing approach. RESULTS: Of the 2,383 participants, 997 were Indigenous (82.9% First Nations, 14.9% Métis, 2.2% Inuit). Over half (54.5%) were cisgender male and the average age was 38.9 years. A large proportion (84.0%) reported their mental health as "fair to excellent". High proportions experienced stigma and discrimination (90.2%) and physical, sexual and/or emotional abuse in childhood (87.5%) or with a sexual partner (78.6%). Use of a needle/syringe distribution program (90.5%) and testing for HIV (87.9%) and hepatitis C (87.8%) were high. Prevalence of HIV was 15.4% (78.2% were aware of infection status) and 36.4% were hepatitis C RNA-positive (49.4% were aware of infection status). CONCLUSION: High rates of HIV and hepatitis C were identified. Challenges in access to and maintenance of HIV and hepatitis C care and treatment were noted. This information informs harm reduction strategies, including the need to scale-up awareness of prophylaxis in a culturally relevant manner.

Laboratory-confirmed COVID-19 in children and youth in Canada, January 15-April 27, 2020.

Understanding the epidemiology of COVID-19 among children and youth in Canada will help to inform public health measures in settings where children gather. As of April 27, 2020, provinces and territories provided the Public Health Agency of Canada with detailed information on 24,079 cases, of which 3.9% (n=938) were younger than 20 years of age. The detection rate per 100,000 population was lower in this age group (11.9 per 100,000), compared with those aged 20-59 years (72.4 per 100,000) and 60 and older (113.6 per 100,000). The median age among those younger than 20 years of age was 13 years, and cases were distributed equally across male and female genders. Among provinces and territories with more than 100 cases, 1.6% to 9.8% of cases were younger than 20 years of age. Cases in this age group were more likely to be asymptomatic: 10.7% compared with 2.4% in those aged 20-59 years and 4.1% in those aged 60 and older. Children and youth experienced severe outcomes less often, but 2.2% (n=15/672) of cases within this age group were severe enough to require hospitalization. Based on available exposure information, 11.3% (n=59/520) of cases aged younger than 20 years had no known contact with a case. Canadian findings align with those of other countries.

National findings from the Tracks survey of people who inject drugs in Canada, Phase 4, 2017-2019.

Background: The Tracks survey of people who inject drugs (PWID) collected data in 14 sentinel sites across Canada (2017-2019). Objective: To describe the prevalence of human immunodeficiency virus (HIV) and hepatitis C and associated risk behaviours and to examine trends over time. Methods: Information regarding socio-demographics, social determinants of health, use of prevention services and testing, drug use, risk behaviours, and HIV and hepatitis C testing, care and treatment was collected through interviewer-administered questionnaires. Biological samples were tested for HIV, hepatitis C antibodies and hepatitis C ribonucleic acid (RNA). Descriptive statistics were calculated and trends over time were assessed. Results: Of the 2,383 participants, 65.6% were cisgender male, 42.2% were Indigenous, 48.0% completed some high school or less, 62.6% lived in unstable housing and 75.7% had ever been incarcerated. Average age was 40.1 years. The majority experienced stigma and discrimination (88.7%) and physical, sexual and/or emotional abuse in childhood (85.0%) or with a sexual partner (75.9%). The majority reported use of a needle/syringe distribution program (90.1%) and tested for HIV (90.5%) and hepatitis C (90.9%).Among participants who had ever had sex, the majority (59.2%) reported inconsistent condom use during vaginal and/or anal sex with a casual sex partner. Prevalence of HIV was 10.3% (82.9% were aware of infection status) and many (36.9%) were hepatitis C RNA-positive (50.1% were aware of infection status).Most surveillance indicators remained relatively stable from Phase 1 to Phase 4. Changes were found in substances used, and improvements were noted related to HIV and hepatitis C prevalence and care cascade indicators. Conclusion: Many PWID in Canada were living in unstable housing and experienced high levels of stigma and discrimination. Prevalence of HIV and hepatitis C was high in some areas. These findings contribute to the evidence base used to inform targeted prevention and control measures.

Historical trends and projected hospital admissions for chronic hepatitis C infection in Canada: a birth cohort analysis.

BACKGROUND: Much of the recent increase in hospital admission rates and mortality associated with hepatitis C in Canada is believed to be because of a higher prevalence of hepatitis C virus infection among those born between 1945 and 1965 (the baby boomer generation). We explored the effects of birth cohort on the rates of and projected trends in hospital admissions associated with hepatitis C. METHODS: The hospital records of 17 344 inpatients with a diagnosis of chronic hepatitis C and liver disease, including liver cancer, were extracted from the Canadian Discharge Abstract Database for April 2004 to March 2011. For each 5-year birth cohort from 1915 to 1984, regression analysis was used to estimate the temporal trends associated with the average age of the cohort during the study period. Future hospital admissions were predicted based on the assumption that past trends would continue. RESULTS: Hospital admissions associated with hepatitis C and liver disease increased an average of 6.0% (95% confidence interval [CI] 4.4%-7.7%) a year over the study period. As of 2010, hospital admission rates were highest for the 1950-1954 and 1955-1959 birth cohorts, at 17.6 (95% CI 13.2-23.5) and 13.7 (95% CI 10.3-18.2) times the rate for the 1970-1974 birth cohort. The corresponding same-age rate ratios predicted under a status quo scenario were 3.6 (95% CI 2.3-4.9) and 3.4 (95% CI 2.1-4.7). Same-age rate ratios were significantly higher for the four 5-year birth cohorts between 1950 and 1969 compared with other birth cohorts. INTERPRETATION: Hospital admissions associated with chronic hepatitis C and liver disease were significantly higher for the 1950-1954 and 1955-1959 birth cohorts than for most other birth cohorts. Without further interventions, the disease burden associated with hepatitis C will continue to increase for most birth cohorts, likely peaking after age 70 years. The substantial disease burden emerging in younger birth cohorts should be monitored.

A systematic review of HIV testing among Canadian populations.

OBJECTIVE: Regular HIV testing and early detection leads to timely treatment. Appropriate treatment and care can prevent disease progression in the individual and prevent onwards transmission within the community. This review describes HIV testing coverage in populations disproportionately affected by HIV and in the general population in Canada. METHODS: A search of published and grey literature on HIV testing uptake in Canada was conducted. Studies reporting quantitative data on testing practices (ever tested, recent testing, and regular testing), published in either English or French from 2008-2012, were included. Studies that involved testing for immigration or prenatal purposes, and post-intervention studies, were excluded. Included studies were assessed using a modified version of the Public Health Agency of Canada's Descriptive Study Critical Appraisal Tool. Pooled prevalence for percent ever tested was calculated for subpopulations and heterogeneity was estimated using the I2 statistic. SYNTHESIS: A total of 26 studies were included in the review. The highest rates of ever having been tested were among people who inject drugs (90.6%) and inmates (90.4%); followed by men who have sex with men (83.0%); Aboriginal peoples (55.5%); and the general population (32.8%). Limited information was available on regular and recent testing. CONCLUSION: HIV testing can reduce the number of undiagnosed cases in Canada. Future research should focus on testing coverage in certain populations, and on the extent to which populations engage in regular testing.

The impact of HIV treatment as prevention in the presence of other prevention strategies: lessons learned from a review of mathematical models set in resource-rich countries.

OBJECTIVE: We aimed to assess the potential prevention benefits of HIV treatment as prevention (TasP) in resource-rich countries and examine the potential interactions between TasP and other prevention strategies by reviewing mathematical models of TasP. METHOD: Multiple databases were searched for mathematical models published in the previous 5 years (from July 2007 to July 2012). The nine models located were set in Canada, Australia and the United States. RESULTS: These models' predictions suggested that the impact of expanding treatment rates on expected new infections could range widely, from no decrease to a decrease of 76%, depending on the time horizon, assumptions and the form of TasP modeled. Increased testing, reducing sexually transmitted infections and reducing risky practices were also predicted to be important strategies for decreasing expected new infections. Sensitivity analysis suggests that current uncertainties such as the effectiveness of highly active antiretroviral therapy outside of heterosexual transmission, less than ideal adherence, and risk compensation, could impact on the success of TasP at the population level. CONCLUSION: The results from large scale pilots and community randomized controlled trials will be useful in demonstrating how well this prevention approach works in real world settings, and in identifying the factors that are needed to support its effectiveness.

Impact of statistical adjustment for frequency of venue attendance in a venue-based survey of men who have sex with men.

Venue sampling is a common sampling method for populations of men who have sex with men (MSM); however, men who visit venues frequently are more likely to be recruited. While statistical adjustment methods are recommended, these have received scant attention in the literature. We developed a novel approach to adjust for frequency of venue attendance (FVA) and assess the impact of associated bias in the ManCount Study, a venue-based survey of MSM conducted in Vancouver, British Columbia, Canada, in 2008-2009 to measure the prevalence of human immunodeficiency virus and other infections and associated behaviors. Sampling weights were determined from an abbreviated list of questions on venue attendance and were used to adjust estimates of prevalence for health and behavioral indicators using a Bayesian, model-based approach. We found little effect of FVA adjustment on biological or sexual behavior indicators (primary outcomes); however, adjustment for FVA did result in differences in the prevalence of demographic indicators, testing behaviors, and a small number of additional variables. While these findings are reassuring and lend credence to unadjusted prevalence estimates from this venue-based survey, adjustment for FVA did shed important insights on MSM subpopulations that were not well represented in the sample.

Risk practices among aboriginal people who inject drugs in New South Wales, Australia.

This paper describes patterns of injecting drug use and blood borne virus (BBV)-related risk practices among Australian Aboriginal and non-Aboriginal people who inject drugs (PWID). A total of 588 participants, 120 of whom self-identified as Aboriginal completed a questionnaire. Aboriginal participants were more likely to have been in prison (37.6 vs. 16.5 %), to inject daily (72.7 vs. 55.0 %), to share ancillary equipment (64.9 vs. 44.8 %) and less likely to know about BBV transmission (72.0 vs. 87.7 %) and treatment (47.2 vs. 67.6 %). Aboriginal participants used services such as BBV testing and drug treatment at a comparable rate to non-Aboriginal participants. The findings suggest that Aboriginal PWID are at greater risk for acquiring BBV. The prison setting should be used to deliver health promotion information and risk reduction messages. More information is needed on Aboriginal people's access and use of services to ensure beneficial services are received in the most appropriate settings.

Does drug and alcohol use undermine concordance between doctors' assessments of major depression and patients' scores on a screening tool for depression among gay men attending general practice?

General practitioners (GPs) identify that depression can be difficult to diagnose in populations with high rates of alcohol and other drug (AOD) use. This is a particular concern with gay men who are a population known to engage in high rates of AOD use and who are vulnerable to depression. This paper uses data from 563 gay men and their GPs to describe concordance between assessments of major depression and, in particular, whether AOD use undermines concordance. Data were collected as part of a larger study of male patients and GPs at high HIV-caseload general practices in Australia. Concordance was measured by comparing patients' scores on the Patient Health Questionnaire-9 screening tool, which is based on the Diagnostic and Statistical Manual of Mental Disorders IV criteria, and GPs' ratings of the likelihood of depression for each participant. We observed high concordance between GPs' assessments of major depression and patients' scores on the PHQ-9 (79% agreement), although our analysis also suggested that concordance was better when it related to cases in which there was no depression. The high concordance observed in our study did not appear to be undermined by gay male patients' AOD use, with the exception of frequent use of crystal methamphetamine. Here, men who reported frequent use of methamphetamine were significantly less likely to have concordant assessments (adjusted odds ratio 0.3, 95% CI 0.1-0.8). Overall, GPs appear to identify depression among many of their gay male patients. While GPs should be aware of the potential complications presented by frequent crystal methamphetamine use, other AOD use may have less impact on the diagnosis of depression.

Respondent-driven sampling and the recruitment of people with small injecting networks.

Respondent-driven sampling (RDS) is a form of chain-referral sampling, similar to snowball sampling, which was developed to reach hidden populations such as people who inject drugs (PWID). RDS is said to reach members of a hidden population that may not be accessible through other sampling methods. However, less attention has been paid as to whether there are segments of the population that are more likely to be missed by RDS. This study examined the ability of RDS to capture people with small injecting networks. A study of PWID, using RDS, was conducted in 2009 in Sydney, Australia. The size of participants' injecting networks was examined by recruitment chain and wave. Participants' injecting network characteristics were compared to those of participants from a separate pharmacy-based study. A logistic regression analysis was conducted to examine the characteristics independently associated with having small injecting networks, using the combined RDS and pharmacy-based samples. In comparison with the pharmacy-recruited participants, RDS participants were almost 80% less likely to have small injecting networks, after adjusting for other variables. RDS participants were also more likely to have their injecting networks form a larger proportion of those in their social networks, and to have acquaintances as part of their injecting networks. Compared to those with larger injecting networks, individuals with small injecting networks were equally likely to engage in receptive sharing of injecting equipment, but less likely to have had contact with prevention services. These findings suggest that those with small injecting networks are an important group to recruit, and that RDS is less likely to capture these individuals.

Syringe coverage in an Australian setting: does a high level of syringe coverage moderate syringe sharing behaviour?

We examined individual-level syringe coverage among 417 people who inject drugs who were recruited from pharmacies in New South Wales in 2009. There was a U-shaped distribution of syringe coverage with many people having very high (51%) or very low (23%) coverage. Overall, two-thirds of respondents (63%) reported adequate coverage (≥ 100%). Respondents who had not used a needle and syringe program in the previous month were more likely to report inadequate coverage (AOR 2.25, 95% CI 1.25-4.05) as were those who reported daily or more frequent injecting (AOR 3.69, 95% CI 2.00-6.81). Inadequate syringe coverage was not independently associated with receptive needle sharing. The level of syringe coverage was high among this sample, and met targets set out by UNAIDS and other organisations. We found that inadequate syringe coverage was not independently correlated with receptive needle sharing, possibly because coverage is sufficient to diminish the relationship between syringe availability and sharing behaviours.

Comparing 'doctor' and 'patient' beliefs about the role of illicit drug use in gay men's depression.

High rates of both illicit drug use and depression are consistently reported among gay men. However, little is known about how beliefs about drug use shape clinical encounters between gay men and health professionals, and that in turn affect clinical communication and care, particularly in relation to depression. We compared 'doctor' and 'patient' beliefs about the role of illicit drug use in gay men's depression. Semi-structured interviews were conducted during August-December 2006 with 16 general medical practitioners working in seven 'gay-friendly' practices in Sydney, Adelaide and a rural-coastal city in New South Wales, and during February-May 2008 with 40 gay men with depression recruited through four Sydney and Adelaide practices. A thematic analysis of these two sets of interviews found that doctors expressed the beliefs that: illicit drug use is related to depression in gay men; illicit drug use impedes effective diagnosis and treatment of depression in gay men; and illicit drug use increases the level of complexity involved in caring for gay men with depression. Gay men expressed the beliefs that: illicit drug use is closely related to depression; illicit drug use can be helpful in dealing with difficult experiences; and illicit drug use is just what you do as a gay man living in a big city. Both groups believed drug use and depression were related, but doctors emphasised the negative outcomes of drug use and interpreted these in relation to health. Gay men believed that drugs could have both negative and positive uses and differentiated between health and social outcomes. While the doctors articulated a pragmatic position on drug use, which is consistent with harm reduction principles, communication with gay male patients could be enhanced if both groups acknowledged their divergent views of illicit drugs and their potential role in mental health.

Use of respondent-driven sampling to enhance understanding of injecting networks: a study of people who inject drugs in Sydney, Australia.

BACKGROUND: Respondent-driven sampling (RDS) is a method for recruiting hidden populations, such as people who inject drugs (PWID). In RDS, participants recruit their peers into the study; who recruited who into the study is tracked, and thus information is gathered on the population's social networks. The purpose of this study was to use information collected from an RDS study of PWID to determine the size and structure of injecting networks and whether network characteristics are associated with sharing injecting equipment. METHODS: A study was launched in Sydney, Australia in 2009 with five seeds, who were asked to recruit three participants each into the survey. This process was repeated until the target sample size was reached. The median size of injecting networks and the homophily (a measure of in-group affiliation) of different subgroups were calculated. Participants' information was linked with that of their recruiter to form dyads, and multivariate analysis was conducted to determine whether dyad and injecting network characteristics were associated with sharing injecting equipment within the dyads. RESULTS: The injecting networks were large, the lowest median subgroup network size being 12. Homophily estimates indicated a lack of strong ties both within and across groups. In the multivariate analysis, factors significantly associated with sharing injecting equipment within dyads were feeling very close to their recruiter and having one or both members of the dyad identify as Aboriginal or Torres Strait Islander and one or both members having not been tested for hepatitis C in the previous year. CONCLUSION: RDS provided valuable information on injecting networks in Sydney. PWID were shown to be socially connected with a large number of other injectors, and affiliations were formed without regard to demographic or drug use characteristics. Linking information from the recruits with that of their recruiter was a useful way of organizing information to gain a more complete understanding of risk behaviour.

Conducting a respondent-driven sampling survey with the use of existing resources in Sydney, Australia.

BACKGROUND: Respondent-driven sampling (RDS) is a form of chain-referral sampling that is increasingly being used for HIV behavioural surveillance. When used for surveillance purposes, a sampling method should be relatively inexpensive and simple to operate. This study examined whether an RDS survey of people who inject drugs (PWID) in Sydney, Australia, could be successfully conducted through the use of minimal and existing resources. METHOD: The RDS survey was conducted on the premises of a local needle and syringe program (NSP) with some adjustments to take into account the constraints of existing resources. The impact of the survey on clients and on staff was examined by summarizing NSP service data and by conducting post-survey discussions with NSP staff. RESULTS: From November 2009 till March 2010, 261 participants were recruited in 16 waves. A significant increase was found in the number of services provided by the NSP during and after data collection. Generally, staff felt that the survey had a positive impact by exposing a broader group of people to the NSP. However, conducting the survey may have led to privacy issues for NSP clients due to an increased number of people gathering around the NSP. CONCLUSIONS: This study shows that RDS can be conducted with the use of minimal and existing resources under certain conditions (e.g., use of a self-administered questionnaire and no biological samples taken). A more detailed cost-utility analysis is needed to determine whether RDS' advantages outweigh potential challenges when compared to simpler and less costly convenience methods.

Sampling methods used in developed countries for behavioural surveillance among men who have sex with men.

The aim of this review was to develop an overview of the sampling methods used in developed countries for behavioural surveillance among men who have sex with men. We abstracted information from peer-reviewed and non-peer-reviewed publications and, when needed, contacted first authors and surveillance authorities. Out of the 40 developed countries, 26 surveillance systems were identified in 23 countries. These surveillance systems made use of one or a combination of: venue-based sampling (n = 16); web-based sampling (n = 11); gay press/mail-out (n = 8); or respondent-driven sampling (n = 4). Differences in the sampling methods used were found by year of implementation and by region. More information is needed to better assess the strengths and limitations of the range of sampling methods. There was substantial variation in the way sampling methods were applied, most especially in venue-based sampling. To improve the ability to compare indicators across countries, key elements of the sampling methods should be standardized.