No abstract

Background: Ratios of different immune cell populations (i.e., monocyte-to-lymphocyte, neutrophil-to-lymphocyte, and platelet-to-lymphocyte ratios) have been studied as a means of predicting future tuberculosis (TB) disease risk or to assist in the diagnosis of incident TB disease. No studies to-date, however, have evaluated the potential of these ratios to predict or assist in the diagnosis of incident TB infection-the first step in the natural history of TB disease. Methods: In this prospective study, we evaluated the complete blood count (CBC)-derived metrics of monocyte-tolymphocyte ratio (MLR), neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) as predictors of future TB infection risk or aids in the diagnosis of TB infection among 145 Tanzanian adolescents enrolled in the DAR-901 vaccine trial, using paired CBCs and interferon-gamma release assays (IGRAs) obtained at 0, 60 and 720 days after study enrollment. Results: At baseline, there were no significant differences between study participants who remained persistently IGRA negative throughout the study period and those who subsequently converted to IGRA positive with respect to MLR (0.18 vs 0.17, p = 0.10), NLR (0.88 vs 1.02, p = 0.08), or PLR (115 vs 120, p = 0.28). Similarly, no significant differences were noted with respect to MLR, NLR, and PLR between IGRA converters and time-matched negative controls at the time of IGRA conversion. With respect to other blood cell measures, however, there were modest but significant differences between IGRA negatives and IGRA converters with respect to red blood cell count (4.8 vs 4.6 × 10 6 cells/mcL, p = 0.008), hemoglobin (12.6 vs 12.3 g/dL, p = 0.01), and hematocrit (38.8 vs 37.8%, p = 0.005).

Introduction: Global AIDS-related deaths have declined by only 10% among adolescents since its peak in 2003. This is disproportionately low compared to a decline of 74% among children aged 0-9 years old. We determined the magnitude of, and predictors of mortality among adolescents and young adults living with HIV on antiretroviral therapy (ART) in Dar-es-Salaam, Tanzania. Methods: A retrospective cohort study was conducted among adolescents (aged 10-19) and young adults (aged 20-24) living with HIV and enrolled in care and treatment centres in Dar es Salaam, Tanzania between January 2015 and December 2019. Data were analysed using STATA version 16. Cumulative hazard curves were used to estimate and illustrate 1-year mortality. Predictors for mortality were assessed by the Fine and Gray competing risk regression model. Sub-hazard ratios (SHR) and 95% confidence intervals (95% CI) were then reported. Results: A total of 15,874 young people living with HIV were included: 4916 (31.3%) were adolescents and 10,913 (68.7%) were young adults. A total of 3843 (77.5%) adolescents and 9517 (87.2%) young adults were female. Deaths occurred in 2.3% (114/4961) of adolescents and 1.2% (135/10,913) of young adults (p < 0.001). Over a follow-up of 9292 person-years, the mortality rate was 3.8 per 100 person years [95% CI 3.2-4.6/100 person-years] among adolescents and 2.1 per 100 personyears among young adults [95% CI 1.8-2.5/100 person-years]. Independent predictors of mortality among adolescents were male sex (adjusted (SHR) aSHR = 1.90, 95% CI: 1.3-2.8), CD4 count < 200 cells/mm 3 (aSHR = 2.7, 95% CI: 1.4-5.0) and attending a private health facility (aSHR = 1.7, 95% CI: 1.1-2.5). Predictors of mortality among young adults were CD4 count < 200 cells/mm 3 (aSHR = 2.8, 95% CI 1.7-4.5), being underweight (aSHR = 2.1, 95% CI: 1.4-3.3) and using nevirapine-based therapy (aHR = 8.3, 95% CI: 3.5-19.5). Conclusions:The mortality rate for persons living with HIV and on ART in Tanzania was significantly higher in adolescents than young adults. Age-and sex-specific risk factors identify targets for intervention to reduce mortality among affected adolescents and young adults.

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) can be transmitted between people through respiratory droplets (droplet particles are >5-10 μm in diameter). We conducted an invitro experiment to determine the filtration efficiency for selected face masks (cloth and medical face masks and N95 respirators) to bacteria with a size (0.5-1.5 μm in diameter) smaller than SARS-CoV-2 respiratory droplet. Bacteria suspension was prepared using normal saline (NaCl) and bacteria (Staphylococcus aureus and Escherichia coli) and maintained at a turbidity of 0.5 MacFarland. The suspensions was put in a 100ml plastic spray bottle (with an approximated 250 μl and flow rate of 31.5 ft3/min per spray) and then a single spray was performed to the test masks. Swabbing was done to unsprayed side of the test mask within 0 and after 4 hrs. The swab was streaked on CLED media then incubated for 48 hours at 37oC in ambient air. Bacterial filtration efficiency (BFE) was determined as the proportions of colony forming units (CFUs) between the test and control mask. The selected face masks had BFE of 100% and >99% for medical and double layer cotton cloth masks, respectively. This study supports the use of cotton cloth (at least double layer) face coverings in public settings where other social distancing measures are difficult to maintain to prevent the spread of infection from the wearer.

The novel Coronavirus disease 2019 (COVID-19) presents a major threat to public health but can be prevented by safe and effective COVID-19 vaccines. Vaccine acceptance among healthcare workers (HCWs) is essential to promote uptake. This study, aimed to determine the COVID-19 vaccination uptake and hesitancy and its associated factors among HCWs in Tanzania. We employed a convergent-parallel mixed-methods design among 1368 HCWs across health facilities in seven geographical zones in Tanzania in 2021. We collected quantitative data by using an interviewer-administered questionnaire and qualitative data, using in-depth interviews and focus group discussions. Participants in the quantitative aspect were conveniently selected whereas those in the qualitative aspect were purposively selected based on their role in patient care, management, and vaccine provision. Stata software version 16.1 was used in the analysis of quantitative data and thematic analysis for the qualitative data. Multiple logistic regression was used to assess the determinants of COVID-19 vaccine uptake. The median age of 1368 HCWs was 33, and the interquartile range was 28–43 years; 65.6% were aged 30+ years, and 60.1% were females. Over half (53.4%) of all HCWs received the COVID-19 vaccine, 33.6% completely refused, and 13% chose to wait. HCWs aged 40+ years, from lower-level facilities (district hospitals and health centers), who worked 6+ years, and with perceived high/very high risk of COVID-19 infection had significantly higher odds of vaccine uptake. The qualitative data revealed misinformation and inadequate knowledge about COVID-19 vaccine safety and efficacy as the key barriers to uptake. Nearly half of all HCWs in Tanzania are still unvaccinated against COVID-19. The predominance of contextual influence on COVID-19 vaccine uptake calls for interventions to focus on addressing contextual determinants, focusing on younger HCWs’ population, short working duration, those working at different facility levels, and providing adequate vaccine knowledge.