JCJohn Chalker

John Chalker

*This is an algorithmically generated author record based on publicly available information.

Current Organizations / Institutes

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Previous Organizations / Institutes

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John Chalker has a total of 52 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    Can formalizing links among community health workers, accredited drug dispensing outlet dispensers, and health facility staff increase their collaboration to improve prompt access to maternal and child care? A qualitative study in Tanzania

    by Angel Dillip, Suleiman Kimatta, Martha Embrey, John C Chalker, Richard Valimba, Mariam Malliwah, John Meena, Rachel Lieber, Keith Johnson

    In Tanzania, progress toward achieving the 2015 Millennium Development Goals for maternal and newborn health was slow. An intervention brought together community health workers, health facility staff, and accredited drug dispensing outlet (ADDO) dispensers to improve maternal and newborn health through a mechanism of collaboration and referral. This study explored barriers, successes, and promising approaches to increasing timely access to care by linking the three levels of health care provision. The study was conducted in the Kibaha district, where we applied qualitative approaches with in-depth interviews and focus group discussions. In-depth interview participants included retail drug shop dispensers (36), community health workers (45), and health facility staff members (15). We conducted one focus group discussion with district officials and four with mothers of newborns and children under 5 years old. Relationships among the three levels of care improved after the linkage intervention, especially for ADDO dispensers and health facility staff who previously had no formal communication pathway. The study participants perceptions of success included improved knowledge of case management and relationships among the three levels of care, more timely access to care, increased numbers of patients/customers, more meetings between community health workers and health facility staff, and a decrease in child and maternal mortality. Reported challenges included stock-outs of medicines at the health facility, participating ADDO dispensers who left to work in other regions, documentation of referrals, and lack of treatment available at health facilities on the weekend. The primary issue that threatens the sustainability of the intervention is that local council health management team members, who are responsible for facilitating the linkage, had not made any supervision visits and were therefore unaware of how the program was running. The study highlights the benefits of approaches that link different levels of care providers to improve access to maternal and child health care. To strengthen this collaboration further, health campaign platforms should include retail drug dispensers as a type of community health care provider. To increase linkage sustainability, the council health management team needs to develop feasible supervision plans.


  • Open Access

    What roles do accredited drug dispensing outlets in Tanzania play in facilitating access to antimicrobials? Results of a multi-method analysis

    by John C Chalker, Catherine Vialle-Valentin, Jafary Liana, Romuald Mbwasi, Innocent A Semali, Bernard Kihiyo, Elizabeth Shekalaghe, Angel Dillip, Suleiman Kimatta, Richard Valimba, et al.

    People in low-income countries purchase a high proportion of antimicrobials from retail drug shops, both with and without a prescription. Tanzania’s accredited drug dispensing outlet (ADDO) program includes dispenser training, enforcement of standards, and the legal right to sell selected antimicrobials. We assessed the role of ADDOs in facilitating access to antimicrobials. We purposively chose four regions, randomly selected three districts and five wards per district. Study methods included interviews at 1200 households regarding care-seeking for acute illness and knowledge about antimicrobials; mystery shoppers visiting 306 ADDOs posing as a caregiver of a child with 1) pneumonia, 2) mild acute respiratory infection (ARI), or 3) a runny nose and request for co-trimoxazole; and audits of antimicrobial availability and prices at 84 public health facilities (PHFs) and 96 ADDOs. Four hundred sixty seven (76 %) members from 367 (77 %) households had recently sought care outside the home for acute illness; 128 had purchased antimicrobials, of which 61 % had been recommended by a doctor or nurse and 32 % by an ADDO dispenser. Only 29 % obtained the antimicrobial at a PHF, whereas, 48 % purchased them at an ADDO. Most thought that ADDOs are convenient place for care, usually have needed medicines, and have high quality services and products, contrasting with 66 % who reported dissatisfaction with PHF waiting times and 56 % with medicine availability. One-third (34 %) of mystery shoppers presenting the mild ARI scenario were inappropriately sold an antimicrobial and 85 % were sold one on request; encouragingly, 99 % presenting a case of pneumonia received either an antimicrobial, referral to a trained provider, or request to bring the child for examination. Overall, 63 and 60 % of the 15 tracer antimicrobials were in stock in ADDOs and PHFs, respectively; ADDOs had significantly more antimicrobial formulations for children available (83 vs. 51 %). Of 369 records of antimicrobial sales in 47 ADDOs, 63 % were dispensed on prescription. ADDOs have increased access to antimicrobials in Tanzania. Community members see them as integral to the health system. Antimicrobials are overused due to poor ADDO dispensing, poor PHF prescribing, and inappropriate public demand. Multi-pronged interventions are needed to address all determinants.


  • Open Access

    What motivates antibiotic dispensing in accredited drug dispensing outlets in Tanzania? A qualitative study

    by Angel Dillip, Martha Embrey, Elizabeth Shekalaghe, Dennis Ross-Degnan, Catherine Vialle-Valentin, Suleiman Kimatta, Jafary Liana, Edmund Rutta, Richard Valimba, John Chalker

    Tanzania introduced the accredited drug dispensing outlet (ADDO) program more than a decade ago. Previous evaluations have generally shown that ADDOs meet defined standards of practice better than non-accredited outlets. However, ADDOs still face challenges with overuse of antibiotics for acute respiratory infections (ARI) and simple diarrhea, which contributes to the emergence of drug resistance. This study aimed to explore the attitudes of ADDO owners and dispensers toward antibiotic dispensing and to learn how accreditation has influenced their dispensing behavior. The study used a qualitative approach. We conducted in-depth interviews with ADDO owners and dispensers in Ruvuma and Tanga regions where the government implemented the ADDO program under centralized and decentralized approaches, respectively; a secondary aim was to compare differences between the two regions. Findings indicate that the ADDO program has brought about positive changes in knowledge of dispensing practices. Respondents were able to correctly explain treatment guidelines for ARI and diarrhea. Almost all dispensers and owners indicated that unnecessary use of antibiotics contributed to antimicrobial resistance. Despite this knowledge, translating it to appropriate dispensing practice is still low. Dispensers’ behavior is driven by customer demand, habit (“mazoea”), following inappropriate health facility prescriptions, and the need to make a profit. Although the majority of dispensers reported that they had intervened in situations where customers asked for antibiotics unnecessarily, they tended to give in to clients’ requests. Small variations were noted between the two study regions; for example, some dispensers in Ruvuma reported sending clients with incorrect prescriptions back to the health facility, a practice that may reflect regional differences in ADDO implementation and in Integrated Management of Childhood Illness training. Dispensers in rural settings reported more challenges in managing ARI and diarrhea than their urban counterparts did. To reduce inappropriate antibiotic use, integrated interventions must include communities, health facilities, and ADDOs. Periodic refresher training with an emphasis on communication skills is crucial in helping dispensers deal with customers who demand antibiotics. Responsible authorities should ensure that ADDOs always have the necessary tools and resources available.


  • Open Access

    Appointment systems are essential for improving chronic disease care in resource-poor settings: learning from experiences with HIV patients in Africa

    by John C. Chalker, Anita K. Wagner, Göran Tomson, Keith Johnson, Rolf Wahlström, Dennis Ross-Degnan, on behalf of the International Network for the Rational Use of Drugs Initiative on Adherence to Antiretroviral Therapy (INRUD-IAA)

    Lessons learned from treating patients with HIV infection can inform care systems for other chronic conditions. For antiretroviral treatment, attending appointments on time correlates with medication adherence; however, HIV clinics in East Africa, where attendance rates vary widely, rarely include systems to schedule appointments or to track missed appointments or patient follow-up. An introduction of low-cost, paper-based patient appointment and tracking systems led to an improvement in timely clinic attendance rates and tracking missing patients. An effective appointment system is critical to managing patients with chronic conditions and can be introduced in resource-limited settings, possibly without having to add staff.


  • Open Access

    Facility-level intervention to improve attendance and adherence among patients on anti-retroviral treatment in Kenya—a quasi-experimental study using time series analysis

    by Patrick Boruett, Dorine Kagai, Susan Njogo, Peter Nguhiu, Christine Awuor, Lillian Gitau, John Chalker, Dennis Ross-Degnan, Rolf Wahlström, Göran Tomson

    Achieving high rates of adherence to antiretroviral therapy (ART) in resource-poor settings comprises serious, but different, challenges in both the first months of treatment and during the life-long maintenance phase. We measured the impact of a health system-oriented, facility-based intervention to improve clinic attendance and patient adherence. This was a quasi-experimental, longitudinal, controlled intervention study using interrupted time series analysis. The intervention consisted of (1) using a clinic appointment diary to track patient attendance and monitor monthly performance; (2) changing the mode of asking for self-reported adherence; (3) training staff on adherence concepts, intervention methods, and use of monitoring data; (4) conducting visits to support facility teams with the implementation. We conducted the study in 12 rural district hospitals (6 intervention, 6 control) in Kenya and randomly selected 1894 adult patients over 18 years of age in two cohorts: experienced patients on treatment for at least one year, and newly treated patients initiating ART during the study. Outcome measures were: attending the clinic on or before the date of a scheduled appointment, attending within 3 days of a scheduled appointment, reporting perfect adherence, and experiencing a gap in medication supply of more than 14 days. Among experienced patients, the percentage attending the clinic on or before a scheduled appointment increased in both level (average total increase immediately after intervention) (+5.7%; 95% CI = 2.1, 9.3) and trend (increase per month) (+1.0% per month; 95% CI = 0.6, 1.5) following the intervention, as did the level and trend of those keeping appointments within three days (+4.2%; 95% CI = 1.6, 6.7; and +0.8% per month; 95% CI = 0.6, 1.1, respectively). The relative difference between the intervention and control groups based on the monthly difference in visit rates increased significantly in both level (+6.5; 95% CI = 1.4, 11.6) and trend (1.0% per month; 95% CI = 0.2, 1.8) following the intervention for experienced patients attending the clinic within 3 days of their scheduled appointments. The decrease in the percentage of experienced patients with a medication gap greater than 14 days approached statistical significance (-11.3%; 95% CI = -22.7, 0.1), and the change seemed to persist over 11 months after the intervention. All facility staff used appointment-keeping data to calculate adherence and discussed outcomes regularly. The appointment-tracking system and monthly performance monitoring was strengthened, and patient attendance was improved. Scale-up to national level may be considered.


  • Open Access

    Measuring adherence to antiretroviral treatment in resource-poor settings: The feasibility of collecting routine data for key indicators

    by Inrud- Iaa, John C Chalker, Tenaw Andualem, Lillian N Gitau, Joseph Ntaganira, Celestino Obua, Hailu Tadeg, Paul Waako, Dennis Ross-Degnan

    An East African survey showed that among the few health facilities that measured adherence to antiretroviral therapy, practices and definitions varied widely. We evaluated the feasibility of collecting routine data to standardize adherence measurement using a draft set of indicators.


  • Open Access

    Measuring adherence to antiretroviral treatment in resource-poor settings: The clinical validity of key indicators

    by Dennis Ross-Degnan, Inrud Iaa, Marsha Pierre-Jacques, Fang Zhang, Hailu Tadeg, Lillian Gitau, Joseph Ntaganira, Robert Balikuddembe, John Chalker, Anita K Wagner

    Access to antiretroviral therapy has dramatically expanded in Africa in recent years, but there are no validated approaches to measure treatment adherence in these settings.


  • Urgent Need for Coordination in Adopting Standardized Antiretroviral Adherence Performance Indicators

    by John Chalker, Anita Wagner, Goran Tomson, Richard Laing, Keith Johnson, Rolf Wahlström, Dennis Ross-Degnan


  • Monitoring Adherence and Defaulting for Antiretroviral Therapy in 5 East African Countries: An Urgent Need for Standards

    by John Chalker, Tenaw Andualem, Omary Minzi, Joseph Ntaganira, Atieno Ojoo, Paul Waako, Dennis Ross-Degnan

    Objectives: A cross-sectional survey was performed in 24 systems of care providing antiretroviral medications in Ethiopia, Kenya, Rwanda, Tanzania, and Uganda to examine current practices in monitoring rates of treatment adherence and defaulting.