Low- and Middle-Income Country Host Perceptions of Short-Term Experiences in Global Health: A Systematic Review.

PURPOSE: Stakeholders have expressed concerns regarding the impact of visiting trainees and physicians from high-income countries (HICs) providing education and/or short-term clinical care in low- and middle-income countries (LMICs). This systematic review aimed to summarize LMIC host perceptions of visiting trainees and physicians from HICs during short-term experiences in global health (STEGH). METHOD: In September 2018 then again in August 2020, the authors searched 7 databases (PubMed, Embase, Scopus, Web of Science, ERIC, Cochrane Library, Global Index Medicus) for peer-reviewed studies that described LMIC host perceptions of STEGH. They extracted information pertaining to study design, participant demographics, participant perceptions, representation of LMICs and HICs, and HIC visitors' roles and used thematic synthesis to code the text, develop descriptive themes, and generate analytical themes. RESULTS: Of the 4,020 studies identified, 17 met the inclusion criteria. In total, the studies included 448 participants, of which 395 (88%) represented LMICs. The authors identified and organized 42 codes under 8 descriptive themes. They further organized these descriptive themes into 4 analytical themes related to STEGH: (1) sociocultural and contextual differences, (2) institutional and programmatic components, (3) impact on host institutions and individuals, and (4) visitor characteristics and conduct. CONCLUSIONS: STEGH can have both beneficial and detrimental effects on LMIC host institutions and individuals. The authors translated these findings into a set of evidence-based best practices for STEGH that provide specific guidance for LMIC and HIC stakeholders. Moving forward, LMIC and HIC institutions must work together to focus on the quality of their relationships and create conditions in which all stakeholders feel empowered to openly communicate to ensure equity and mutual benefit for all parties.

Circulating B-lymphocytes as potential biomarkers of tuberculosis infection activity.

Accurate biomarkers of Mycobacterium tuberculosis infection activity would significantly improve early diagnosis, treatment and management of M. tuberculosis infection. We hypothesised that circulating B-lymphocytes may be useful biomarkers of tuberculosis (TB) infection status in highly TB-endemic settings. Ex-vivo and in-vitro mycobacteria-specific B-cell ELISPOT assays were used to examine the plasmablast (PB) and memory B-cell (MBC) responses in the peripheral blood of adult, healthy, community controls (n = 151) and of active TB patients (n = 48) living in Uganda. Frequencies of mycobacteria-specific PBs were markedly higher in active TB patients compared to healthy controls, and, conversely, MBCs were markedly higher in the healthy controls compared to active TB patients. In addition, the community controls with evidence of latent TB infection had higher peripheral blood PB and MBC responses than those without evidence of TB infection. These data demonstrate that peripheral blood B-cell responses are differentially modulated during latent and active M. tuberculosis infection, and suggest that the PB to MBC ratio may be a useful biomarker of TB infection activity.

Impact of co-infections and BCG immunisation on immune responses among household contacts of tuberculosis patients in a Ugandan cohort.

BACKGROUND: Tuberculosis incidence in resource poor countries remains high. We hypothesized that immune modulating co-infections such as helminths, malaria, and HIV increase susceptibility to latent tuberculosis infection (LTBI), thereby contributing to maintaining the tuberculosis epidemic. METHODS: Adults with sputum-positive tuberculosis (index cases) and their eligible household contacts (HHCs) were recruited to a cohort study between May 2011 and January 2012. HHCs were investigated for helminths, malaria, and HIV at enrolment. HHCs were tested using the QuantiFERON-TB Gold In-Tube (QFN) assay at enrolment and six months later. Overnight whole blood culture supernatants from baseline QFN assays were analyzed for cytokine responses using an 11-plex Luminex assay. Associations between outcomes (LTBI or cytokine responses) and exposures (co-infections and other risk factors) were examined using multivariable logistic and linear regression models. RESULTS: We enrolled 101 index cases and 291 HHCs. Among HHCs, baseline prevalence of helminths was 9% (25/291), malaria 16% (47/291), HIV 6% (16/291), and LTBI 65% (179/277). Adjusting for other risk factors and household clustering, there was no association between LTBI and any co-infection at baseline or at six months: adjusted odds ratio (95% confidence interval (CI); p-value) at baseline for any helminth, 1.01 (0.39-2.66; 0.96); hookworm, 2.81 (0.56-14.14; 0.20); malaria, 1.06 (0.48-2.35; 0.87); HIV, 0.74 (0.22-2.47; 0.63). HHCs with LTBI had elevated cytokine responses to tuberculosis antigens but co-infections had little effect on cytokine responses. Exploring other risk factors, Th1 cytokines among LTBI-positive HHCs with BCG scars were greatly reduced compared to those without scars: (adjusted geometric mean ratio) IFNγ 0.20 (0.09-0.42), <0.0001; IL-2 0.34 (0.20-0.59), <0.0001; and TNFα 0.36 (0.16-0.79), 0.01. CONCLUSIONS: We found no evidence that co-infections increase the risk of LTBI, or influence the cytokine response profile among those with LTBI. Prior BCG exposure may reduce Th1 cytokine responses in LTBI.