Since the outbreak of the COVID-19 pandemic, most countries have recommended their citizens to adopt social distance, hand hygiene, and face mask wearing. However, wearing face masks has not been well adopted by many citizens. While the reasons are complex, there is a general perception that the evidence to support face mask wearing is lacking, especially for the general public in a community setting. Face mask wearing can block or filter airborne virus-carrying particles through the working of colloid and interface science. This paper assesses current knowledge behind the design and functioning of face masks by reviewing the selection of materials, mask specifications, relevant laboratory tests, and respiratory virus transmission trials, with an overview of future development of reusable masks for the general public. This review highlights the effectiveness of face mask wearing in the prevention of COVID-19 infection.

BackgroundSleep disorders are common and associated with multiple metabolic and psychological derangements. Obstructive sleep apnoea (OSA) is among the most common sleep disorders and an inter-relationship between OSA, insulin resistance, obesity, type 2 diabetes (T2DM) and cardiovascular diseases has been established. Prevalence of sleep disorders in Kenyans, particularly in individuals with T2DM is unknown. We thus aimed to determine prevalence of poor quality of sleep (QOS) and high risk for OSA, among persons with T2DM and determine their associations with socio-demographic and anthropometric variables.MethodsUtilising a Cross- Sectional Descriptive design, QOS and risk for OSA were determined in a randomly selected sample of patients with T2DM (cases) and an age and sex matched comparison group. The validated Pittsburgh Sleep Quality Index (PSQI) and Berlin Questionnaire (BQ) were used to measure QOS and risk for OSA respectively. Associations between poor QOS, high risk for OSA, and socio-demographic and anthropometric variables in cases were evaluated.ResultsFrom 245 randomly selected persons with T2DM attending outpatient clinics, aged over 18 years, 22 were excluded due to ineligibility thus 223 were included in the analysis; 53.8% were females, mean age was 56.8 (SD 12.2) years and mean BMI was 28.8 kg/m2 (SD 4.4). Among them, 119 (53%, CI 95% 46.5–60.2) had poor QOS and 99 (44% CI 95% 37.8–50.9) were at high risk for OSA. Among 112 individuals in comparison group, 33 (29.5%, CI 95% 20.9–38.3) had poor QOS and 9 (8%, CI 95% 3.3–13.4) had high risk for OSA. Cases had a significantly higher probability for poor QOS [OR 2.76 (95% CI 1.7–4.4))] and high risk for OSA [OR 9.1 (95% CI 4.4–19.0)].Higher waist circumference was independently associated with a high risk for OSA in cases.ConclusionsWe demonstrate a high burden of sleep disturbances in patients with T2DM. Our findings may have implications for clinicians to screen for sleep disorders when assessing patients with T2DM and warranting further attention by practitioners and researches in this field.Electronic supplementary materialThe online version of this article (doi:10.1186/s12902-017-0158-6) contains supplementary material, which is available to authorized users.

Background HIV-exposed uninfected (HEU) infants in endemic settings are at high risk of tuberculosis (TB). For infants, progression from primary M. tuberculosis infection to TB disease can be rapid. We assessed whether isoniazid (INH) prevents primary Mtb infection. Methods We conducted a randomized non-blinded controlled trial enrolling HEU infants 6 weeks of age without known TB exposure in Kenya. Participants were randomized (1:1) to 12 months daily INH (10 mg/kg) vs. no INH. Primary endpoint was Mtb infection at end of 12 months, assessed by interferon-gamma release assay QuantiFERON-TB Gold Plus (QFT-Plus) and/or tuberculin skin test (TST, added 6 months after first participant exit). Results Between August 15, 2016 and June 6, 2018, 416 infants were screened, with 300 (72%) randomized to INH or no INH (150 per arm); 2 were excluded due to HIV infection. Among 298 randomized HEU infants, 12-month retention was 96.3% (287/298) and 88.9% (265/298) had primary outcome data. Mtb infection prevalence at 12-months follow-up was 10.6% (28/265); 7.6% (10/132) in INH and 13.5% (18/133) in no INH arms (7.0 vs. 13.4 per 100PY, HR 0.53 [95%CI 0.24-1.14], p=0.11]), and driven primarily by TST positivity (8.6% [8/93] in INH and 18.1% [17/94] in no INH arms; RR 0.48 [95%CI 0.22-1.05], p=0.07). Frequency of severe adverse events was similar between arms (INH 14.0% [21/150] vs. no INH 10.7% [16/150], p=0.38), with no INH-related adverse events. Conclusions Further studies evaluating TB preventive therapy to prevent or delay primary Mtb infection in HEU and other high-risk infants are warranted.

Background: HIV and pregnancy may affect latent TB infection (LTBI) diagnostics. Tuberculin skin test (TST) and newer generation QuantiFERON-TB Gold Plus (QFT-Plus) evaluations in pregnant women living with HIV (WLHIV) and without HIV are lacking. Methods:In this cross-sectional study, pregnant women underwent TST and QFT-Plus testing during antenatal care in Kenya. We estimated LTBI prevalence and TST and QFT-Plus performances. Diagnostic agreement was assessed with kappa statistic, participant characteristics associated with LTBI and HIV were assessed with generalized linear models, and QFT-Plus quantitative responses were assessed with Mann-Whitney U test. Results:We enrolled 400 pregnant women (200 WLHIV/200 HIVnegative women) at median 28 weeks gestation (interquartile range 24-30). Among WLHIV (all on antiretroviral therapy), the median CD4 count was 464 cells/mm 3 (interquartile range 325-654); 62.5% (125) had received isoniazid preventive therapy. LTBI prevalence was 35.8% and similar among WLHIV and HIV-negative women. QFT-Plus testing identified 3-fold more women with LTBI when compared with TST (32% vs. 12%, P , 0.0001). QFT-Plus positivity prevalence was similar regardless of HIV status, although TB-specific antigen responses were lower in WLHIV than in HIVnegative women with LTBI (median QFT-TB1 1.05 vs. 2.65 IU/mL, P = 0.035; QFT-TB2 1.26 vs. 2.56 IU/mL, P = 0.027). TST positivity was more frequent among WLHIV than among HIVnegative women (18.5% vs 4.6%; P , 0.0001).Conclusions: QFT-Plus assay had higher diagnostic yield than TST for LTBI in WLHIV and HIV-negative women despite lower TB-specific antigen responses in WLHIV. Higher TST positivity was observed in WLHIV. LTBI diagnostic performance in the context of pregnancy and HIV has implications for clinical use and prevention studies, which rely on these diagnostics for TB infection entry criteria or outcomes.