Implementation of CDC Guidelines for Recess: A Formative Research Study.

The American Academy of Pediatrics recognizes recess as an essential part of overall child development in schools, impacting children's cognitive, socioemotional and physical health and development. However, recess is often removed from the school curriculum in exchange for more classroom activities. The Centers for Disease Control and Prevention (CDC) and SHAPE America developed Strategies for Recess in Schools to promote high-quality recess through specific actions, yet is not known how these are successfully implemented, particularly, in underserved settings. This formative research study examined the implementation of the CDC strategy in an urban, inner-city charter elementary school to identify barriers and facilitators to successful recess implementation from the perspective of various stakeholders. Thirteen in-depth interviews and focus group discussions were conducted with parents, teachers, recess monitors, and school administrators. Interviews were recorded, transcribed, and coded for thematic analysis, supported by group discussion and analytic memos. Results suggested that although stakeholders recognized the importance of recess, the implementation of the CDC strategy was neither uniformly understood nor implemented, suggesting that additional frameworks may be helpful in implementing the CDC strategy in schools in underserved communities.

Multisystem Inflammatory Syndrome in Children after SARS-CoV-2 Vaccination.

Multisystem inflammatory syndrome in children (MIS-C) is a hyperinflammatory state that occurs after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We present 2 cases of MIS-C after SARS-CoV-2 vaccination; 1 patient had evidence of recent SARS-CoV-2 infection. Our findings suggest that vaccination modulates the pathogenesis of MIS-C.

Supplementing Substance Use Prevention With Sexual Health Education: A Partner-Informed Approach to Intervention Development.

Supplementing substance use prevention with sexual health education would allow educators to address the risk and protective factors that influence both health issues. This streamlined approach may minimize the inefficiencies of multisession, single-purpose interventions. Our team developed a supplemental sexual and reproductive health (SRH) unit to align with an existing evidence-based intervention, LifeSkills Training (LST). This goal of this article is to describe our process, final product, lessons learned, and future directions. Our partner-informed approach took place across three key phases: (1) formative insights, (2) unit development, and (3) pilot implementation. The final supplemental SRH unit is ten, 45-minute sessions offered to seventh- and eighth-grade students and includes a set of learning objectives that are aligned with individual sessions. The supplemental SRH unit also mirrors existing LST modules in length, flow, layout, facilitator instructions, focus on prevention, and utilization of a student workbook. Lessons learned include strategies to effectively incorporate a wide range of ongoing feedback from multiple sources and quickly respond to staff turnover. This partnership approach serves as a model for researchers and practitioners aiming to extend the reach of existing evidence-based programs.

Risk and Protective Factors Associated with Adolescent Food Insecurity in Baltimore.

While emerging evidence is highlighting a growing problem of food insecurity among adolescents in disadvantaged neighborhoods, very little is known about the factors that may either protect or place adolescents at higher risk for food insecurity. The primary objective for this analysis, therefore, was to examine the associations between individual-, family-, and neighborhood-level risks and protective factors and food insecurity among 452 adolescents in Baltimore, Maryland. Results show that nearly 30% of our sample were food insecure (29.4%). Food insecure youth were more likely to be unstably housed (OR 5.17, 1.24-21.62), live in larger households (OR 1.14, 1.08-1.20), and perceive their neighborhoods unsafe (OR 2.37, 1.47-3.83). Protective factors included perceiving both male and female adult support (OR 0.55 and 0.47, respectively), having a higher sense of community belonging (OR 0.91, 0.32-0.95) and having positive perceptions of their neighborhood's physical environment (OR 0.93, 0.88-0.98). These results suggest that strengthening family and neighborhood relations and resources may promote the health of adolescents in disadvantaged urban areas.

Who Adolescents Trust May Impact Their Health: Findings from Baltimore.

This study is one of the first to explore the relevance of trust to the health of adolescents living in a disadvantaged urban setting. The primary objectives were to determine the differences in the sociodemographic characteristics between adolescents who do and do not trust and to examine the associations between trust and health. Data were drawn from the Well-Being of Adolescents in Vulnerable Environments (WAVE) study, which is a cross-sectional global study of adolescents in very low-income urban settings conducted in 2011-2013. This paper focused on 446 adolescents in Baltimore as it was the primary site where trust was explicitly measured. For the main analyses, six health outcomes were examined: (1) self-rated health; (2) violence victimization; (3) binge drinking; (4) marijuana use; (5) post-traumatic stress disorder (PTSD); and (6) condom use at last sex. Independent variables included sociodemographic variables (age, gender, current school enrolment, perceived relative wealth, and family structure) and two dimensions of trust: community trust (trust in individuals/groups within neighborhood) and institutional trust (trust in authorities). The results show that more than half the sample had no trust in police, and a high proportion had no trust in other types of authority. Among girls, those with higher levels of community trust were less likely to be victimized and involved in binge drinking. Meanwhile, girls with higher levels of institutional trust were more likely to use a condom and less likely to have used marijuana. Among boys, those with higher levels of community trust were more likely to use a condom, while those with higher levels of institutional trust were less likely to use marijuana, but more likely binge drink. Overall, this study highlights the importance of trust for adolescent health. Most surprising were the differences in the associations between boys and girls with regard to the type of trust and specific health outcome that was significant.

A mixed methods study to examine the influence of the neighborhood social context on adolescent health service utilization.

BACKGROUND: While adolescents' access and utilization of health services is critical for ensuring their health, very few seek care, and if they do, it is primarily from family members, friends, or other non-formal sources of care. Examining the influence of the social context on adolescent health care seeking behaviors may provide us with a better understanding for how interventions can increase adolescents' utilization of formal health care services. METHODS: The study is based on qualitative and quantitative data collected as part of the Well Being of Adolescents in Vulnerable Environments (WAVE) study, one of the first global studies to focus on very disadvantaged urban adolescents (aged 15-19 years) across five diverse sites, which include: Baltimore (USA), Ibadan (Nigeria), Johannesburg (South Africa), New Delhi (India), and Shanghai (China). Qualitative data was based on numerous methodologies, including key informant interviews, a Photovoice exercise, community mapping, focus groups and in-depth interviews. Quantitative data was gathered from a cross-sectional Audio Computer Assisted Self Interview (ACASI) survey that was administered to approximately 450-500 adolescents per site, yielding a total of 2,393 adolescents. Respondent-driven sampling was used to ensure the sample include out-of-school youth and unstably housed youth who are often underrepresented in school-based or household-based samples. RESULTS: While adolescents in Baltimore, New Delhi, and Johannesburg were more likely to seek health services if they felt illness symptoms, a fairly large proportion of adolescents indicated that even when they needed health care, they didn't seek it. In Johannesburg, more than 30 % of adolescents did not seek care even when they knew it was needed. Similarly, nearly a quarter of adolescents in Baltimore and in Shanghai indicated not seeking care when needed. Qualitative data indicated that adolescents exhibited a general lack of trust in providers and often felt embarrassed or stigmatized for seeking services. Multivariate analysis revealed that perceived fear and exposure to community violence was associated with a decreased likelihood of seeking care, while adult support from the home increased adolescents' likelihood to seek care in Baltimore and Johannesburg. CONCLUSIONS: Adolescent health care seeking patterns vary substantially by setting and gender. Neighborhood and family environments are important contexts in which health seeking behaviors are shaped. Efforts to connect adolescents to health care will need to target neighborhood safety as well as trust and support among adults outside of provider settings.

Effect of a Comprehensive School-Based Health Center on Academic Growth in K-8th Grade Students.

OBJECTIVE: School-based health centers (SBHCs) improve health care access, but associations with educational outcomes are mixed and limited for elementary and middle school students. We investigated whether students enrolled in a comprehensive SBHC demonstrated more growth in standardized math and reading assessments over 4 school years versus nonenrolled students. We also explored changes in absenteeism. METHODS: Participants were students enrolled in 2 co-located Title I schools from 2015-19 (1 elementary, 1 middle, n = 2480). Analysis of math and reading was limited to students with baseline and postbaseline scores (math n = 1622; reading n = 1607). Longitudinal regression models accounting for within-subject clustering were used to estimate the association of SBHC enrollment with academic scores and daily absenteeism, adjusting for grade, sex, body mass index category, health conditions, baseline outcomes (scores or absenteeism), and outcome pretrends. RESULTS: More than 70% of SBHC-enrolled students had math (1194 [73.6%]) and reading 1186 [73.8%]) scores. Enrollees were more likely than nonenrollees to have asthma (39.7% vs 19.6%) and overweight/obesity (42.4% vs 33.6%). Adjusted baseline scores were significantly lower in math and reading for enrollees. Mean change from baseline for enrollees exceeded nonenrollees by 3.5 points (95% confidence interval [CI]: 2.2, 4.8) in math and 2.1 points (95% CI: 0.9, 3.3) in reading. The adjusted rate of decrease in daily absenteeism was 10.8% greater for enrollees (incident rate ratio 0.772 [95% CI: 0.623, 0.956]) than nonenrollees (incident rate ratio 0.865 [95% CI: 0.696, 1.076]). CONCLUSIONS: SBHC enrollees had greater health and educational risk but demonstrated more growth in math and reading and less absenteeism than nonenrollees.

Identifying and preventing fraudulent responses in online public health surveys: Lessons learned during the COVID-19 pandemic.

Web-based survey data collection has become increasingly popular, and limitations on in-person data collection during the COVID-19 pandemic have fueled this growth. However, the anonymity of the online environment increases the risk of fraudulent responses provided by bots or those who complete surveys to receive incentives, a major risk to data integrity. As part of a study of COVID-19 and the return to in-person school, we implemented a web-based survey of parents in Maryland between December 2021 and July 2022. Recruitment relied, in part, on social media advertisements. Despite implementing many existing best practices, we found the survey challenged by sophisticated fraudsters. In response, we iteratively improved survey security. In this paper, we describe efforts to identify and prevent fraudulent online survey responses. Informed by this experience, we provide specific, actionable recommendations for identifying and preventing online survey fraud in future research. Some strategies can be deployed within the data collection platform such as careful crafting of survey links, Internet Protocol address logging to identify duplicate responses, and comparison of client-side and server-side time stamps to identify responses that may have been completed by respondents outside of the survey's target geography. Other strategies can be implemented during the survey design phase. These approaches include the use of a 2-stage design in which respondents must be eligible on a preliminary screener before receiving a personalized link. Other design-based strategies include within-survey and cross-survey validation questions, the addition of "speed bump" questions to thwart careless or computerized responders, and the use of optional open-ended survey questions to identify fraudsters. We describe best practices for ongoing monitoring and post-completion survey data review and verification, including algorithms to expedite some aspects of data review and quality assurance. Such strategies are increasingly critical to safeguarding survey-based public health research.

The protective effect of SARS-CoV-2 antibodies in Scottish healthcare workers.

BACKGROUND: Healthcare workers (HCWs) are believed to be at increased risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. It is not known to what extent the natural production of antibodies to SARS-CoV-2 is protective against re-infection. METHODS: A prospective observational study of HCWs in Scotland (UK) from May to September 2020 was performed. The Siemens SARS-CoV-2 total antibody assay was used to establish seroprevalence in this cohort. Controls, matched for age and sex to the general local population, were studied for comparison. New infections (up to 2 December 2020) post antibody testing were recorded to determine whether the presence of SARS-CoV-2 antibodies protects against re-infection. RESULTS: A total of 2063 health and social care workers were recruited for this study. At enrolment, 300 HCWs had a positive antibody test (14.5%). 11 out of 231 control sera tested positive (4.8%). HCWs therefore had an increased likelihood of a positive test (OR 3.4, 95% CI 1.85-6.16; p<0.0001). Dentists were most likely to test positive. 97.3% of patients who had previously tested positive for SARS-CoV-2 by reverse transcriptase (RT)-PCR had positive antibodies. 18.7% had an asymptomatic infection. There were 38 new infections with SARS-CoV-2 in HCWs who were previously antibody negative, and one symptomatic RT-PCR-positive re-infection. The presence of antibodies was therefore associated with an 85% reduced risk of re-infection with SARS-CoV-2 (hazard ratio 0.15, 95% CI 0.06-0.35; p=0.026). CONCLUSION: HCWs were three times more likely to test positive for SARS-CoV-2 than the general population. Almost all infected individuals developed an antibody response, which was 85% effective in protecting against re-infection with SARS-CoV-2.

A prospective school-based study of abdominal pain and other common somatic complaints in children.

OBJECTIVE: To determine the prevalence and impact of pediatric abdominal pain (AP). STUDY DESIGN: Prospective cohort study (12/2005-06/2006), with gastrointestinal and other symptoms assessed weekly. Anxiety, depression, functional disability, quality of life, somatization, coping, school absenteeism and medical care were assessed in 237 students in the third through eighth grades (11.8 years; 134 girls) from 2 public schools weekly. Complete data were obtained on 4606 of 5175 (89%) possible questionnaires. RESULTS: Seventy-two percent of children reported >1 somatic symptom weekly, and 45% of children reported >1 gastrointestinal symptom weekly. The weekly prevalence of AP was 38%, and 90% of children reported AP at least once. AP persisted >4 consecutive weeks in 52% of children and was associated with higher anxiety (P < .001) and depression (P < .001) scores and worse quality of life (P < .001). Twenty-three percent of children missed school for AP (average, 2.3 days), and 10% of parents of those children missed work (average, 1.9 days). Presence of AP (P < .001) was independently associated with school absences. Four children (2%) sought medical attention. CONCLUSIONS: AP is common in school-age children and is associated with worse quality of life, psychological co-morbidities, school absenteeism, and parental work absences.

The frequency of pregnancy and exposure to cytomegalovirus infections among women with a young child in day care.

OBJECTIVE: The purpose of this study was to determine the frequency of pregnancy and exposure to cytomegalovirus (CMV) among mothers contemplating a possible additional pregnancy and with a child less than 2 years of age in group day care. STUDY DESIGN: We performed a prospective observational study that included a demographic questionnaire and serologic and virologic monitoring of mothers and their children in day care. RESULTS: Of 60 women, 62% were seronegative and 20% had a child shedding CMV. Of the 60 women, 23 women or 38% (95% CI, 0.27-0.51) became pregnant on average 10 months after enrollment. During pregnancy, 8 or 35% (95% CI, 0.19-0.55) of these pregnant women had a child in day care who shed CMV. CONCLUSION: These results illustrate the potential magnitude of the public problem associated with exposure to a silent viral infection during pregnancy. Our data, when extrapolated to the US population, estimate that every 2 years between 31,000 and 168,000 susceptible pregnant women will be exposed to CMV by an infected child.

Antivirals for cytomegalovirus infection in neonates and infants: focus on pharmacokinetics, formulations, dosing, and adverse events.

Cytomegalovirus (CMV) infection is very common throughout the world, and has become more of a pediatric clinical concern given the high incidence of congenital CMV infections as well as the increasing numbers of immunocompromised patients. Because of this, the need for antiviral therapies in infants and neonates is growing. Currently, there are four antivirals available that are active against CMV: ganciclovir, valganciclovir, foscarnet, and cidofovir. At this time, none have approved indications for use in children. Although there are limited data regarding the dose, pharmacokinetics (PK), safety, and adverse events for some of these antivirals, ganciclovir, and its oral prodrug valganciclovir, have been the best studied in the infant and neonate populations. In general, pharmaceutical PK studies in young children are limited by the constraints of sampling difficulties and blood volume requirements; fewer sampling times and studies may be available for drug evaluation. Given this caveat, ganciclovir and valganciclovir PK in children thus far appears to follow a monocompartmental model, contrary to what has been described in adults. However, when normalized for weight, the volume of distribution, clearance, and half-life of ganciclovir are similar to those found in adults. Given the findings that ganciclovir (and thus valganciclovir) clearance is directly proportionate to renal function, care must be taken when administering the drug to patients with impaired renal function. Recent studies evaluating valganciclovir PK in infants (at a dose of 16 mg/kg every 12 hours) have shown similar areas under the plasma concentration-time curve (AUCs) to intravenous ganciclovir (at a dose of 6 mg/kg every 12 hours), and that these AUCs remain quite stable over a number of weeks. As seen in adults, oral ganciclovir has a low bioavailability (4.8% in a pediatric analysis) and is therefore a poor alternative for treating serious CMV infections. Neutropenia is the most frequent toxicity associated with ganciclovir and valganciclovir therapy, whereas significant (and possibly irreversible) renal toxicity can be seen with cidofovir. Foscarnet administration can also result in renal toxicity as well as significant electrolyte imbalances. Several of these drugs have potential toxicities that are of concern, including carcinogenesis, teratogenesis, and azospermia (ganciclovir, valganciclovir, and cidofovir) and deposition into bone or dentition (foscarnet) that may have significant implications when treating an infant. Given these potential ill effects, careful consideration of the indications for the clinical use of these antivirals is necessary before using them for CMV infection in neonates and infants.

Role of the Elementary School Cafeteria Environment in Fruit, Vegetable, and Whole-Grain Consumption by 6- to 8-Year-Old Students.

OBJECTIVE: Examine how the physical cafeteria environment contributes to 6- to 8-year-olds' school food consumption. DESIGN: Cross-sectional observational study. Before-and-after lunch tray photos taken with iPads to capture food selection and consumption. SETTING: 10 New York City public elementary school cafeterias. PARTICIPANTS: A total of 382 students aged 6-8 years who ate lunch in the cafeteria on observation days. MAIN OUTCOME MEASURES: Fruit, vegetable, or whole-grain consumption. ANALYSIS: Pearson's chi-square and multivariate logistic regression assessed associations between cafeteria environmental factors (time to eat lunch, noise, and crowding) and vegetable, fruit, and/or whole-grain consumption with 95% confidence, adjusted for school-level demographics and clustered by school. RESULTS: Approximately 70% of students selected fruits, vegetables, and/or whole grains. When selected, consumption was 25%, 43%, and 57%, respectively. Longer time to eat lunch was associated with higher consumption of fruits (odds ratio [OR] = 2.0; 95% confidence interval [CI], 1.1-3.8; P = .02) and whole grains (OR = 2.1; 95% CI, 1.003-4.2; P < .05). Quieter cafeterias were associated with eating more vegetables (OR = 3.9; 95% CI, 1.8-8.4; P < .001) and whole grains (OR = 2.7; 95% CI, 2.6-4.7; P < .001). Less crowding was associated with eating more fruit (OR = 2.3; 95% CI, 1.03-5.3; P = .04) and whole grains (OR = 3.3; 95% CI, 1.9-5.6; P < .001). CONCLUSIONS AND IMPLICATIONS: Healthy food consumption by 6- to 8-year-old students is associated with cafeteria crowding, noise, and time to eat lunch. Implementing and enforcing changes to the cafeteria environment mandated by wellness policies may reduce plate waste.

Cost and consultation patterns of abdominal pain in Uruguayan children.

BACKGROUND: Children with abdominal pain (AP) have worse quality of life and poorer social functioning and school attendance than their healthy peers. This is the first investigation of consultation patterns and costs of AP in South American children. PATIENTS AND METHODS: All data were collected from Unidad Coronaria Movil in Montevideo, Uruguay. Diagnoses of all house calls during a 4-year period (January 2002 through December 2005) were analyzed. Variances in consultation patterns based on sex and age were investigated. Supply and personnel costs were analyzed and prorated to obtain an accurate estimate of the cost per house call and outpatient visit. RESULTS: A total of 125,945 in-home visits and 1588 outpatient consultations were analyzed. Consultation rates for AP peaked among patients 7 to 9 years of age. Female subjects 9 to 14 years of age consulted significantly more frequently for AP than male subjects in the same age group. The average AP consultation accounted for approximately 3.8% of the per capita health care spending in Uruguay in 2005. CONCLUSIONS: AP is a global health problem that is present across ethnicities, nationalities, and geographic locations and is associated with significant health care expenditure.

Avidity maturation following immunization with two human cytomegalovirus (CMV) vaccines: a live attenuated vaccine (Towne) and a recombinant glycoprotein vaccine (gB/MF59).

Two human cytomegalovirus (CMV) vaccines have been previously evaluated for their immunogenicity: a recombinant gB/MF59 vaccine and an attenuated strain of CMV (Towne). In healthy adults, we measured the antibody avidity maturation indices that occurred after vaccination with each. For Towne, administered as a single dose, the rise in IgG antibody avidity to CMV glycoprotein gB occurred slowly and continued for 24 months post-immunization. For gB/MF59, administered as two priming doses and a booster dose given at 6 months, the booster rapidly induced IgG antibodies to gB whose avidity was maximal at 7 months after the initial priming dose. Both vaccines induced antibody levels and avidity maturation indices that equaled those induced by wild-type virus suggesting that both vaccines may be effective in controlling CMV infections.

Avidity of antibodies to cytomegalovirus in HIV-seropositive patients with and without CMV retinitis.

Antibodies of high avidity may protect the fetus from CMV infection, but the association of avidity with other CMV infections is unknown. To determine if anti-CMV antibody avidity is altered in HIV-seropositive patients, either untreated or treated with HAART, and to determine if alterations in avidity are associated with CMV retinitis, we obtained sera from 164 CMV-seropositive adults: 68 were HIV-seronegative healthy adults and 96 were HIV seropositive. Of the HIV-positive, 57 had no current or prior evidence of CMV retinitis (29 were being treated with HAART, and 28 were receiving no therapy when sampled), and 39 had either active CMV retinitis or were immunorestored by HAART with quiescent CMV retinitis. IgG antibody avidity was determined for each serum run in duplicate using an EIA assay and 5M urea as a dissociating agent. After correction for the significantly higher levels of IgG antibodies to CMV in the HIV-seropositive sera as compared to the normal healthy individuals, both HIV-infected and HIV-uninfected individuals had nearly identical average avidity indices (avidity index = 76). There was also no significant difference in average avidity index between HAART-treated and untreated patients, or between patients with active and immunorestored, quiescent CMV retinitis). These results indicate antibody avidity is unaltered in HIV disease and does not play an important role in the pathogenesis of AIDS-related CMV disease.

Adolescents' perceptions of health from disadvantaged urban communities: findings from the WAVE study.

The Well-being of Adolescents in Vulnerable Environments (WAVE) is a global study of young people living in disadvantaged urban communities from Baltimore, MD, Johannesburg, South Africa, Shanghai, China, New Delhi, India and Ibadan, Nigeria. WAVE was launched in the summer of 2011 to: 1) explore adolescents' perceived health and their top health challenges; and 2) describe the factors that adolescents perceive to be related to their health and health care utilization. Researchers in each site conducted in-depth interviews among adolescents; community mapping and focus groups among adolescents; a Photovoice methodology, in which adolescents were trained in photography and took photos of the meaning of 'health' in their communities; and key informant interviews among adults who work with young people. A total 529 participants from across the sites were included in the analysis. Findings from the study showed that gender played a large role with regards to what adolescents considered as their top health challenges. Among females, sexual and reproductive health problems were primary health challenges, whereas among males, tobacco, drug, and alcohol consumption was of highest concern, which often resulted into acts of violence. Personal safety was also a top concern among males and females from Baltimore and Johannesburg, and among females in New Delhi and Ibadan. Factors perceived to influence health the most were the physical environment, which was characterized by inadequate sanitation and over-crowded buildings, and the social environment, which varied in influence by gender and site. Regardless of the study site, adolescents did not consider physical health as a top priority and very few felt the need to seek health care services. This study highlights the need to focus on underlying structural and social factors for promoting health and well-being among adolescents in disadvantaged urban environments.

Social capital and vulnerable urban youth in five global cities.

PURPOSE: Social capital is essential for the successful development of young people. The current study examines direct measures of social capital in young people in five urban global contexts. METHODS: The Well-Being of Adolescents in Vulnerable Environments is a global study of young people aged 15-19 years living in disadvantaged, urban settings. Respondent-driven sampling was used to recruit approximately 500 participants from each site. The sample included 2,339 young people (mean age 16.7 years; 47.5% female). We examined the associations between social capital in four domains-family, school, peers, and neighborhood and demographic characteristics-using gender-stratified ordinary least-squares regression. We also examined associations between self-reported health and the four social capital domains, which was minimal. RESULTS: School enrollment was positively associated with social capital for young women in Baltimore, Delhi, and Shanghai; the association was less consistent for young men. The same pattern is true for perceived wealth. Unstable housing was associated with low familial social capital in all groups except young women in Shanghai and young men in Ibadan and Johannesburg. Being raised outside a two-parent family has a widespread, negative association with social capital. Self-reported health had a mainly positive association with social capital with the most consistent association being neighborhood social capital. CONCLUSIONS: Different types of social capital interact with social contexts and gender differently. Strategies that aim to build social capital as part of risk reduction and positive youth development programming need to recognize that social capital enhancement may work differently for different groups and in different settings.

Respondent-driven sampling for an adolescent health study in vulnerable urban settings: a multi-country study.

The global adolescent population is larger than ever before and is rapidly urbanizing. Global surveillance systems to monitor youth health typically use household- and school-based recruitment methods. These systems risk not reaching the most marginalized youth made vulnerable by conditions of migration, civil conflict, and other forms of individual and structural vulnerability. We describe the methodology of the Well-Being of Adolescents in Vulnerable Environments survey, which used respondent-driven sampling (RDS) to recruit male and female youth aged 15-19 years and living in economically distressed urban settings in Baltimore, MD; Johannesburg, South Africa; Ibadan, Nigeria; New Delhi, India; and Shanghai, China (migrant youth only) for a cross-sectional study. We describe a shared recruitment and survey administration protocol across the five sites, present recruitment parameters, and illustrate challenges and necessary adaptations for use of RDS with youth in disadvantaged urban settings. We describe the reach of RDS into populations of youth who may be missed by traditional household- and school-based sampling. Across all sites, an estimated 9.6% were unstably housed; among those enrolled in school, absenteeism was pervasive with 29% having missed over 6 days of school in the past month. Overall findings confirm the feasibility, efficiency, and utility of RDS in quickly reaching diverse samples of youth, including those both in and out of school and those unstably housed, and provide direction for optimizing RDS methods with this population. In our rapidly urbanizing global landscape with an unprecedented youth population, RDS may serve as a valuable tool in complementing existing household- and school-based methods for health-related surveillance that can guide policy.