A measles and rubella vaccine microneedle patch in The Gambia: a phase 1/2, double-blind, double-dummy, randomised, active-controlled, age de-escalation trial.

BACKGROUND: Microneedle patches (MNPs) have been ranked as the highest global priority innovation for overcoming immunisation barriers in low-income and middle-income countries. This trial aimed to provide the first data on the tolerability, safety, and immunogenicity of a measles and rubella vaccine (MRV)-MNP in children. METHODS: This single-centre, phase 1/2, double-blind, double-dummy, randomised, active-controlled, age de-escalation trial was conducted in The Gambia. To be eligible, all participants had to be healthy according to prespecified criteria, aged 18-40 years for the adult cohort, 15-18 months for toddlers, or 9-10 months for infants, and to be available for visits throughout the follow-up period. The three age cohorts were randomly assigned in a 2:1 ratio (adults) or 1:1 ratio (toddlers and infants) to receive either an MRV-MNP (Micron Biomedical, Atlanta, GA, USA) and a placebo (0·9% sodium chloride) subcutaneous injection, or a placebo-MNP and an MRV subcutaneous injection (MRV-SC; Serum Institute of India, Pune, India). Unmasked staff ransomly assigned the participants using an online application, and they prepared visually identical preparations of the MRV-MNP or placebo-MNP and MRV-SC or placebo-SC, but were not involved in collecting endpoint data. Staff administering the study interventions, participants, parents, and study staff assessing trial endpoints were masked to treatment allocation. The safety population consists of all vaccinated participants, and analysis was conducted according to route of MRV administration, irrespective of subsequent protocol deviations. The immunogenicity population consisted of all vaccinated participants who had a baseline and day 42 visit result available, and who had no protocol deviations considered to substantially affect the immunogenicity endpoints. Solicited local and systemic adverse events were collected for 14 days following vaccination. Unsolicited adverse events were collected to day 180. Age de-escalation between cohorts was based on the review of the safety data to day 14 by an independent data monitoring committee. Serum neutralising antibodies to measles and rubella were measured at baseline, day 42, and day 180. Analysis was descriptive and included safety events, seroprotection and seroconversion rates, and geometric mean antibody concentrations. The trial was registered with the Pan African Clinical Trials Registry PACTR202008836432905, and is complete. FINDINGS: Recruitment took place between May 18, 2021, and May 27, 2022. 45 adults, 120 toddlers, and 120 infants were randomly allocated and vaccinated. There were no safety concerns in the first 14 days following vaccination in either adults or toddlers, and age de-escalation proceeded accordingly. In infants, 93% (52/56; 95% CI 83·0-97·2) seroconverted to measles and 100% (58/58; 93·8-100) seroconverted to rubella following MRV-MNP administration, while 90% (52/58; 79·2-95·2) and 100% (59/59; 93·9-100) seroconverted to measles and rubella respectively, following MRV-SC. Induration at the MRV-MNP application site was the most frequent local reaction occurring in 46 (77%) of 60 toddlers and 39 (65%) of 60 infants. Related unsolicited adverse events, most commonly discolouration at the application site, were reported in 35 (58%) of 60 toddlers and 57 (95%) of 60 infants that had received the MRV-MNP. All local reactions were mild. There were no related severe or serious adverse events. INTERPRETATION: The safety and immunogenicity data support the accelerated development of the MRV-MNP. FUNDING: Bill & Melinda Gates Foundation.

Safety of the novel oral poliovirus vaccine type 2 (nOPV2) in infants and young children aged 1 to <5 years and lot-to-lot consistency of the immune response to nOPV2 in infants in The Gambia: a phase 3, double-blind, randomised controlled trial.

BACKGROUND: Novel oral poliovirus vaccine type 2 (nOPV2) has been engineered to improve the genetic stability of Sabin oral poliovirus vaccine (OPV) and reduce the emergence of circulating vaccine-derived polioviruses. This trial aimed to provide key safety and immunogenicity data required for nOPV2 licensure and WHO prequalification. METHODS: This phase 3 trial recruited infants aged 18 to <52 weeks and young children aged 1 to <5 years in The Gambia. Infants randomly assigned to receive one or two doses of one of three lots of nOPV2 or one lot of bivalent OPV (bOPV). Young children were randomised to receive two doses of nOPV2 lot 1 or bOPV. The primary immunogenicity objective was to assess lot-to-lot equivalence of the three nOPV2 lots based on one-dose type 2 poliovirus neutralising antibody seroconversion rates in infants. Equivalence was declared if the 95% CI for the three pairwise rate differences was within the -10% to 10% equivalence margin. Tolerability and safety were assessed based on the rates of solicited adverse events to 7 days, unsolicited adverse events to 28 days, and serious adverse events to 3 months post-dose. Stool poliovirus excretion was examined. The trial was registered as PACTR202010705577776 and is completed. FINDINGS: Between February and October, 2021, 2345 infants and 600 young children were vaccinated. 2272 (96·9%) were eligible for inclusion in the post-dose one per-protocol population. Seroconversion rates ranged from 48·9% to 49·2% across the three lots. The minimum lower bound of the 95% CIs for the pairwise differences in seroconversion rates between lots was -5·8%. The maximum upper bound was 5·4%. Equivalence was therefore shown. Of those seronegative at baseline, 143 (85·6%) of 167 (95% CI 79·4-90·6) infants and 54 (83·1%) of 65 (71·7-91·2) young children seroconverted over the two-dose nOPV2 schedule. The post-two-dose seroprotection rates, including participants who were both seronegative and seropositive at baseline, were 604 (92·9%) of 650 (95% CI 90·7-94·8) in infants and 276 (95·5%) of 289 (92·4-97·6) in young children. No safety concerns were identified. 7 days post-dose one, 78 (41·7%) of 187 (95% CI 34·6-49·1) infants were excreting the type 2 poliovirus. INTERPRETATION: nOPV2 was immunogenic and safe in infants and young children in The Gambia. The data support the licensure and WHO prequalification of nOPV2. FUNDING: Bill & Melinda Gates Foundation.

Tobacco smoking clusters in households affected by tuberculosis in an individual participant data meta-analysis of national tuberculosis prevalence surveys: Time for household-wide interventions?

Tuberculosis (TB) and non-communicable diseases (NCD) share predisposing risk factors. TB-associated NCD might cluster within households affected with TB requiring shared prevention and care strategies. We conducted an individual participant data meta-analysis of national TB prevalence surveys to determine whether NCD cluster in members of households with TB. We identified eligible surveys that reported at least one NCD or NCD risk factor through the archive maintained by the World Health Organization and searching in Medline and Embase from 1 January 2000 to 10 August 2021, which was updated on 23 March 2023. We compared the prevalence of NCD and their risk factors between people who do not have TB living in households with at least one person with TB (members of households with TB), and members of households without TB. We included 16 surveys (n = 740,815) from Asia and Africa. In a multivariable model adjusted for age and gender, the odds of smoking was higher among members of households with TB (adjusted odds ratio (aOR) 1.23; 95% CI: 1.11-1.38), compared with members of households without TB. The analysis did not find a significant difference in the prevalence of alcohol drinking, diabetes, hypertension, or BMI between members of households with and without TB. Studies evaluating household-wide interventions for smoking to reduce its dual impact on TB and NCD may be warranted. Systematically screening for NCD using objective diagnostic methods is needed to understand the actual burden of NCD and inform comprehensive interventions.

Tolerability, safety, and immunogenicity of the novel oral polio vaccine type 2 in children aged 6 weeks to 59 months in an outbreak response campaign in The Gambia: an observational cohort study.

BACKGROUND: Novel oral polio vaccine type 2 (nOPV2) has been used to interrupt circulating vaccine-derived poliovirus type 2 outbreaks following its WHO emergency use listing. This study reports data on the safety and immunogenicity of nOPV2 over two rounds of a campaign in The Gambia. METHODS: This observational cohort study collected baseline symptoms (vomiting, diarrhoea, irritability, reduced feeding, and reduced activity) and axillary temperature from children aged 6 weeks to 59 months in The Gambia before a series of two rounds of a nOPV2 campaign that took place on Nov 20-26, 2021, and March 19-22, 2022. Serum and stool samples were collected from a subset of the participants. The same symptoms were re-assessed during the week following each dose of nOPV2. Stool samples were collected on days 7 and 28, and serum was collected on day 28 following each dose. Adverse events, including adverse events of special interest, were documented for 28 days after each campaign round. Serum neutralising antibodies were measured by microneutralisation assay, and stool poliovirus excretion was measured by real-time RT-PCR. FINDINGS: Of the 5635 children eligible for the study, 5504 (97·7%) received at least one dose of nOPV2. There was no increase in axillary temperature or in any of the baseline symptoms following either rounds of the campaigns. There were no adverse events of special interest and no other safety signals of concern. Poliovirus type 2 seroconversion rates were 70% (95% CI 62 to 78; 87 of 124 children) following one dose of nOPV2 and 91% (85 to 95; 113 of 124 children) following two doses. Poliovirus excretion on day 7 was lower after the second round (162 of 459 samples; 35·3%, 95% CI 31·1 to 39·8) than after the first round (292 of 658 samples; 44·4%, 40·6 to 48·2) of the campaign (difference -9·1%; 95% CI -14·8 to -3·3), showing the induction of mucosal immunity. INTERPRETATION: In a campaign in west Africa, nOPV2 was well tolerated and safe. High rates of seroconversion and evidence of mucosal immunity support the licensure and WHO prequalification of this vaccine. FUNDING: Bill & Melinda Gates Foundation.

Histoplasma Seropositivity in TB Patients in The Gambia: Evidence to Drive Research on a High-Priority Fungal Pathogen.

Background: Inclusion of Histoplasma in the World Health Organization's first Fungal Priority Pathogens List under "high-priority" fungal species highlights the need for robust surveillance of Histoplasma spp. in endemic and underrepresented regions. Despite increasing reports of histoplasmosis in Africa, data on the burden of this fungal disease are sparse in The Gambia. This baseline study examined the human seroprevalence of anti-Histoplasma antibody in a TB patient group in The Gambia, explored associations between seropositivity and demographic and clinical variables, and proposes future research directions. Methods: Biobanked plasma samples were selected from active TB cases with variable HIV infection status. Latex agglutination tests were performed on samples from 52 study participants to detect the presence of anti-Histoplasma antibodies. Potential risk factors for Histoplasma exposure were explored using logistic regression analysis. Results: The sample seroprevalence of anti-Histoplasma antibody was 28.8% (n = 15/52; 95% CI, 17.1%-43.1%). Multivariable logistic regression analysis identified a statistically significant association between Histoplasma seropositivity and age (odds ratio, 0.91; 95% CI, 0.84-0.98; P = .008). Conclusions: This baseline study provides evidence of Histoplasma seropositivity in TB patients in The Gambia and explores risk factors for exposure. The small sample size and use of the LAT in TB and HIV-positive patient groups are significant study limitations. Future research directions are proposed to ascertain the burden of Histoplasma in general and patient populations and explore the context-specific risk factors for exposure and infection in The Gambia.

Association of diabetes, smoking, and alcohol use with subclinical-to-symptomatic spectrum of tuberculosis in 16 countries: an individual participant data meta-analysis of national tuberculosis prevalence surveys.

Background: Non-communicable diseases (NCDs) and NCD risk factors, such as smoking, increase the risk for tuberculosis (TB). Data are scarce on the risk of prevalent TB associated with these factors in the context of population-wide systematic screening and on the association between NCDs and NCD risk factors with different manifestations of TB, where ∼50% being asymptomatic but bacteriologically positive (subclinical). We did an individual participant data (IPD) meta-analysis of national and sub-national TB prevalence surveys to synthesise the evidence on the risk of symptomatic and subclinical TB in people with NCDs or risk factors, which could help countries to plan screening activities. Methods: In this systematic review and IPD meta-analysis, we identified eligible prevalence surveys in low-income and middle-income countries that reported at least one NCD (e.g., diabetes) or NCD risk factor (e.g., smoking, alcohol use) through the archive maintained by the World Health Organization and by searching in Medline and Embase from January 1, 2000 to August 10, 2021. The search was updated on March 23, 2023. We performed a one-stage meta-analysis using multivariable multinomial models. We estimated the proportion of and the odds ratio for subclinical and symptomatic TB compared to people without TB for current smoking, alcohol use, and self-reported diabetes, adjusted for age and gender. Subclinical TB was defined as microbiologically confirmed TB without symptoms of current cough, fever, night sweats, or weight loss and symptomatic TB with at least one of these symptoms. We assessed heterogeneity using forest plots and I2 statistic. Missing variables were imputed through multi-level multiple imputation. This study is registered with PROSPERO (CRD42021272679). Findings: We obtained IPD from 16 national surveys out of 21 national and five sub-national surveys identified (five in Asia and 11 in Africa, N = 740,815). Across surveys, 15.1%-56.7% of TB were subclinical (median: 38.1%). In the multivariable model, current smoking was associated with both subclinical (OR 1.67, 95% CI 1.27-2.40) and symptomatic TB (OR 1.49, 95% CI 1.34-1.66). Self-reported diabetes was associated with symptomatic TB (OR 1.67, 95% CI 1.17-2.40) but not with subclinical TB (OR 0.92, 95% CI 0.55-1.55). For alcohol drinking ≥ twice per week vs no alcohol drinking, the estimates were imprecise (OR 1.59, 95% CI 0.70-3.62) for subclinical TB and OR 1.43, 95% CI 0.59-3.46 for symptomatic TB). For the association between current smoking and symptomatic TB, I2 was high (76.5% (95% CI 62.0-85.4), while the direction of the point estimates was consistent except for three surveys with wide CIs. Interpretation: Our findings suggest that current smokers are more likely to have both symptomatic and subclinical TB. These individuals can, therefore, be prioritised for intensified screening, such as the use of chest X-ray in the context of community-based screening. People with self-reported diabetes are also more likely to have symptomatic TB, but the association is unclear for subclinical TB. Funding: None.

Study protocol for a phase 1/2, single-centre, double-blind, double-dummy, randomized, active-controlled, age de-escalation trial to assess the safety, tolerability and immunogenicity of a measles and rubella vaccine delivered by a microneedle patch in healthy adults (18 to 40 years), measles and rubella vaccine-primed toddlers (15 to 18 months) and measles and rubella vaccine-naïve infants (9 to 10 months) in The Gambia [Measles and Rubella Vaccine Microneedle Patch Phase 1/2 Age De-escalation Trial].

BACKGROUND: New strategies to increase measles and rubella vaccine coverage, particularly in low- and middle-income countries, are needed if elimination goals are to be achieved. With this regard, measles and rubella vaccine microneedle patches (MRV-MNP), in which the vaccine is embedded in dissolving microneedles, offer several potential advantages over subcutaneous delivery. These include ease of administration, increased thermostability, an absence of sharps waste, reduced overall costs and pain-free administration. This trial will provide the first clinical trial data on MRV-MNP use and the first clinical vaccine trial of MNP technology in children and infants. METHODS: This is a phase 1/2, randomized, active-controlled, double-blind, double-dummy, age de-escalation trial. Based on the defined eligibility criteria for the trial, including screening laboratory investigations, 45 adults [18-40 years] followed by 120 toddlers [15-18 months] and 120 infants [9-10 months] will be enrolled in series. To allow double-blinding, participants will receive either the MRV-MNP and a placebo (0.9% sodium chloride) subcutaneous (SC) injection or a placebo MNP and the MRV by SC injection (MRV-SC). Local and systemic adverse event data will be collected for 14 days following study product administration. Safety laboratories will be repeated on day 7 and, in the adult cohort alone, on day 14. Unsolicited adverse events including serious adverse events will be collected until the final study visit for each participant on day 180. Measles and rubella serum neutralizing antibodies will be measured at baseline, on day 42 and on day 180. Cohort progression will be dependent on review of the unblinded safety data by an independent data monitoring committee. DISCUSSION: This trial will provide the first clinical data on the use of a MNP to deliver the MRV and the first data on the use of MNPs in a paediatric population. It will guide future product development decisions for what may be a key technology for future measles and rubella elimination. TRIAL REGISTRATION: Pan-African Clinical Trials Registry 202008836432905 . CLINICALTRIALS: gov NCT04394689.

Infant BCG vaccination and risk of pulmonary and extrapulmonary tuberculosis throughout the life course: a systematic review and individual participant data meta-analysis.

BACKGROUND: BCG vaccines are given to more than 100 million children every year, but there is considerable debate regarding the effectiveness of BCG vaccination in preventing tuberculosis and death, particularly among older children and adults. We therefore aimed to investigate the age-specific impact of infant BCG vaccination on tuberculosis (pulmonary and extrapulmonary) development and mortality. METHODS: In this systematic review and individual participant data meta-analysis, we searched MEDLINE, Web of Science, BIOSIS, and Embase without language restrictions for case-contact cohort studies of tuberculosis contacts published between Jan 1, 1998, and April 7, 2018. Search terms included "mycobacterium tuberculosis", "TB", "tuberculosis", and "contact". We excluded cohort studies that did not provide information on BCG vaccination or were done in countries that did not recommend BCG vaccination at birth. Individual-level participant data for a prespecified list of variables, including the characteristics of the exposed participant (contact), the index case, and the environment, were requested from authors of all eligible studies. Our primary outcome was a composite of prevalent (diagnosed at or within 90 days of baseline) and incident (diagnosed more than 90 days after baseline) tuberculosis in contacts exposed to tuberculosis. Secondary outcomes were pulmonary tuberculosis, extrapulmonary tuberculosis, and mortality. We derived adjusted odds ratios (aORs) using mixed-effects, binary, multivariable logistic regression analyses with study-level random effects, adjusting for the variable of interest, baseline age, sex, previous tuberculosis, and whether data were collected prospectively or retrospectively. We stratified our results by contact age and Mycobacterium tuberculosis infection status. This study is registered with PROSPERO, CRD42020180512. FINDINGS: We identified 14 927 original records from our database searches. We included participant-level data from 26 cohort studies done in 17 countries in our meta-analysis. Among 68 552 participants, 1782 (2·6%) developed tuberculosis (1309 [2·6%] of 49 686 BCG-vaccinated participants vs 473 [2·5%] of 18 866 unvaccinated participants). The overall effectiveness of BCG vaccination against all tuberculosis was 18% (aOR 0·82, 95% CI 0·74-0·91). When stratified by age, BCG vaccination only significantly protected against all tuberculosis in children younger than 5 years (aOR 0·63, 95% CI 0·49-0·81). Among contacts with a positive tuberculin skin test or IFNγ release assay, BCG vaccination significantly protected against tuberculosis among all participants (aOR 0·81, 95% CI 0·69-0·96), participants younger than 5 years (0·68, 0·47-0·97), and participants aged 5-9 years (0·62, 0·38-0·99). There was no protective effect among those with negative tests, unless they were younger than 5 years (0·54, 0·32-0·90). 14 cohorts reported on whether tuberculosis was pulmonary or extrapulmonary (n=57 421). BCG vaccination significantly protected against pulmonary tuberculosis among all participants (916 [2·2%] in 41 119 vaccinated participants vs 334 [2·1%] in 16 161 unvaccinated participants; aOR 0·81, 0·70-0·94) but not against extrapulmonary tuberculosis (106 [0·3%] in 40 318 vaccinated participants vs 38 [0·2%] in 15 865 unvaccinated participants; 0·96, 0·65-1·41). In the four studies with mortality data, BCG vaccination was significantly protective against death (0·25, 0·13-0·49). INTERPRETATION: Our results suggest that BCG vaccination at birth is effective at preventing tuberculosis in young children but is ineffective in adolescents and adults. Immunoprotection therefore needs to be boosted in older populations. FUNDING: National Institutes of Health.

Neutrophils Contribute to Severity of Tuberculosis Pathology and Recovery From Lung Damage Pre- and Posttreatment.

BACKGROUND: Despite microbiological cure, about 50% of tuberculosis (TB) patients have poor lung recovery. Neutrophils are associated with lung pathology; however, CD16/CD62L-defined subsets have not been studied in TB. Using flow cytometry, we monitored frequencies, phenotype, and function of neutrophils following stimulation with Mycobacterium tuberculosis (Mtb) whole cell lysate (WCL) and ESAT-6/CFP-10 fusion protein (EC) in relation to lung pathology. METHODS: Fresh blood from 42 adult, human immunodeficiency virus (HIV)-negative TB patients were analyzed pre- and post-therapy, with disease severity determined using chest radiography and bacterial load. Flow cytometry was used to monitor frequencies, phenotype, and function (generation of reactive oxygen species [ROS], together with CD11b, tumor necrosis factor, and interleukin 10 [IL-10] expression) of neutrophils following 2-hour stimulation with Mtb-specific antigens. RESULTS: Total neutrophils decreased by post-treatment compared to baseline (P = .0059); however, CD16brCD62Lbr (segmented) neutrophils increased (P = .0031) and CD16dimCD62Lbr (banded) neutrophils decreased (P = .038). Banded neutrophils were lower in patients with severe lung damage at baseline (P = .035). Following WCL stimulation, ROS from segmented neutrophils was higher in patients with low Mtb loads even after adjusting for sex (P = .038), whereas IL-10-expressing CD16dimCD62Llo cells were higher in patients with mild damage (P = .0397) at baseline. CONCLUSIONS: High ROS generation, low levels of banded neutrophils, and high levels of IL-10-expressing CD16dimCD62Llo neutrophils are associated with reduced lung pathology at diagnosis. Hence, neutrophils are potential early indicators of TB severity and promising targets for TB host-directed therapy.

Major Neutrophil-Derived Soluble Mediators Associate With Baseline Lung Pathology and Post-Treatment Recovery in Tuberculosis Patients.

Background: The inflammatory response to Mycobacterium tuberculosis results in variable degrees of lung pathology during active TB (ATB) with central involvement of neutrophils. Little is known about neutrophil-derived mediators and their role in disease severity at baseline and recovery upon TB treatment initiation. Methods: 107 adults with confirmed pulmonary TB were categorised based on lung pathology at baseline and following successful therapy using chest X-ray scores (Ralph scores) and GeneXpert bacterial load (Ct values). Plasma, sputum, and antigen-stimulated levels of MMP1, MMP3, MMP8, MMP9, MPO, S100A8/9, IL8, IL10, IL12/23(p40), GM-CSF, IFNγ, and TNF were analysed using multiplex cytokine arrays. Results: At baseline, neutrophil counts correlated with plasma levels of MMP8 (rho = 0.45, p = 2.80E-06), S100A8 (rho = 0.52, p = 3.00E-08) and GM-CSF (rho = 0.43, p = 7.90E-06). Levels of MMP8 (p = 3.00E-03), MMP1 (p = 1.40E-02), S100A8 (p = 1.80E-02) and IL12/23(p40) (p = 1.00E-02) were associated with severe lung damage, while sputum MPO levels were directly linked to lung damage (p = 1.80E-03), Mtb load (p = 2.10E-02) and lung recovery (p = 2.40E-02). Six months of TB therapy significantly decreased levels of major neutrophil-derived pro-inflammatory mediators: MMP1 (p = 4.90E-12 and p = 2.20E-07), MMP8 (p = 3.40E-14 and p = 1.30E-05) and MMP9 (p = 1.60E-04 and p = 1.50E-03) in plasma and sputum, respectively. Interestingly, following H37Rv whole cell lysate stimulation, S100A8 (p = 2.80E-02), MMP9 (p = 3.60E-02) and MPO (p = 9.10E-03) levels at month 6 were significantly higher compared to baseline. Sputum MMP1 (p = 1.50E-03), MMP3 (p = 7.58E-04), MMP9 (p = 2.60E-02) and TNF (p = 3.80E-02) levels were lower at month 6 compared to baseline in patients with good lung recovery. Conclusion: In this study, patients with severe lung pathology at baseline and persistent lung damage after treatment were associated with higher plasma and sputum levels of major pro-inflammatory neutrophil-derived mediators. Interestingly, low sputum MPO levels were associated with severe lung damage, higher Mtb burden and low recovery. Our data suggest that therapeutic agents which target these mediators should be considered for future studies on biomarkers and host-directed therapeutic approaches against TB-related lung pathology and/or lung recovery.

BCG Vaccine Protection Against Mycobacterium tuberculosis Infection by Level of Exposure in The Gambia.

In Indonesia, BCG vaccine protection against Mycobacterium tuberculosis infection decreased with increasing exposure to the pathogen. We aimed to validate these findings in Africa. Poisson regression was used to estimate BCG protection, stratified by pathogen exposure using an exposure score, against enzyme-linked immunospot assay conversion at 3 months in 220 Gambian case contacts. Although the interaction between BCG and exposure was not significant (P = .13), BCG protection was strongest in the lowest-exposure tertile (relative risk, 0.35 [95% confidence interval, .15-.82; P = .02] vs 0.50 [.30-.83; P = .008] and 0.71 (.45-1.13; P = .1] for the middle and highest-exposure tertiles, respectively. These results are consistent with those from Indonesia.

Knowledge, attitude and practice towards tuberculosis in Gambia: a nation-wide cross-sectional survey.

BACKGROUND: Early diagnosis and treatment of tuberculosis (TB) are the mainstay of global and national TB control efforts. However, the gap between expected and reported cases persists for various reasons attributable to the TB services and care-seeking sides of the TB care cascade. Understanding individual and collective perspectives of knowledge, attitudes, beliefs and other social circumstances around TB can inform an evidence-based approach in engaging communities and enhance their participation in TB case detection and treatment. METHODS: The study was conducted during the Gambian survey of TB prevalence. This was a nationwide cross-sectional multistage cluster survey with 43,100 participants aged ≥15 years in 80 clusters. The study sample, a random selection of 10% of the survey population within each cluster responded to a semi-structured questionnaire administered by trained fieldworkers to assess the knowledge, attitudes and practice of the participants towards TB. Overall knowledge, attitude and practice scores were dichotomised using the computed mean scores and analysed using descriptive, univariable and multivariable logistic regression. RESULTS: All targeted participants (4309) were interviewed. Majority were females 2553 (59.2%), married 2614 (60.7%), had some form of education 2457 (57%), and were unemployed 2368 (55%). Although 3617 (83.9%) of the participants had heard about TB, only 2883 (66.9%) were considered to have good knowledge of TB. Overall 3320 (77%) had unfavourable attitudes towards TB, including 1896 (44%) who indicated a preference for staying away from persons with TB rather than helping them. However, 3607(83.7%) appeared to have the appropriate health-seeking behaviours with regard to TB as 4157 (96.5%) of them were willing to go to the health facility if they had symptoms suggestive of TB. CONCLUSIONS: About 3 in 10 Gambians had poor knowledge on TB, and significant stigma towards TB and persons with TB persists. Interventions to improve TB knowledge and address stigma are required as part of efforts to reduce the burden of undiagnosed TB in the country.

Delay in the diagnosis of pulmonary tuberculosis in The Gambia, West Africa: A cross-sectional study.

OBJECTIVES: To investigate the pattern of tuberculosis (TB) care initiation and risk factors for TB diagnostic delay in The Gambia. METHODS: In this cross-sectional study, adult patients diagnosed with pulmonary TB (pTB) in public facilities in the Greater Banjul Area of The Gambia were consecutively recruited from October 2016 to March 2017. Diagnostic delay was defined as >21 days from the onset of at least one symptom suggestive of pTB to diagnosis. Logistic regression analyses were used to investigate risk factors for diagnostic delay. RESULTS: Overall, 216 pTB patients were included in the study; the median (Interquartile Range (IQR)) age was 30 (23-39) years and 167 (77%) were male patients. Of the 216 patients, 110 (50.9%) of them initiated care-seeking in the formal and informal private sector and 181/216 (83.8%) had TB diagnostic delay. The median (IQR) duration from the onset of symptoms to TB diagnosis was 34 (28-56) days. Age groups 18-29 years (aOR 3.2; 95% CI 1.2-8.8 [p = 0.02]) and 30-49 years (aOR 5.1; 95% CI 1.6-16.2 [p = 0.006]) and being employed (aOR 4.2; 95% CI 1.7-10.5 [p = 0.002]) were independent risk factors for TB diagnostic delay. CONCLUSION: There is considerable TB diagnostic delay in The Gambia, and this is likely to be worsened by the COVID-19 pandemic.

Mycobacterium tuberculosis-specific plasmablast levels are differentially modulated in tuberculosis infection and disease.

BACKGROUND: While T cell responses to Mycobacterium tuberculosis (Mtb) have been extensively studied, the role of B-cells and antibodies are less well characterised. The aim of this study was to assess levels of Mtb-specific IgG + plasmablasts across the Mtb infection spectrum. METHODS: Patients with active TB were analysed at baseline and 6 months of therapy (n = 20).Their exposed household contacts (HHC) included individuals with latent TB infection (LTBI; n = 20); evident at baseline; individuals with a negative Tuberculin Skin Test (TST) at baseline who became; positive at 6 months (converters; n = 11) and those who remained negative (non-converters; n = 10). An e x-vivo B-cell ELISPOT was performed to analyse plasmablast responses. RESULTS: Frequencies of ESAT-6/CFP-10 (EC)- but not Whole Cell Lysate (WCL)-specific plasmablasts were significantly higher in patients with active TB pre-treatment compared to post-treatment (p = 0.002) and compared to HHC with LTBI (p < 0.0001). Conversely, total IgG + plasmablasts were significantly decreased in TB patients at baseline. No difference was seen in levels of plasmablasts between TST converters and non-converters at baseline. CONCLUSIONS: We show that EC-specific plasmablast levels are differentially modulated during TB infection and disease, with levels highest during active TB. These data provide new insights into TB biomarker development and avenues for novel immune interventions.

Changes in Transcript, Metabolite, and Antibody Reactivity During the Early Protective Immune Response in Humans to Mycobacterium tuberculosis Infection.

BACKGROUND: Strategies to prevent Mycobacterium tuberculosis (Mtb) infection are urgently required. In this study, we aimed to identify correlates of protection against Mtb infection. METHODS: Two groups of Mtb-exposed contacts of tuberculosis (TB) patients were recruited and classified according to their Mtb infection status using the tuberculin skin test (TST; cohort 1) or QuantiFERON (QFT; cohort 2). A negative reading at baseline with a positive reading at follow-up classified TST or QFT converters and a negative reading at both time points classified TST or QFT nonconverters. Ribonucleic acid sequencing, Mtb proteome arrays, and metabolic profiling were performed. RESULTS: Several genes were found to be differentially expressed at baseline between converters and nonconverters. Gene set enrichment analysis revealed a distinct B-cell gene signature in TST nonconverters compared to converters. When infection status was defined by QFT, enrichment of type I interferon was observed. A remarkable area under the curve (AUC) of 1.0 was observed for IgA reactivity to Rv0134 and an AUC of 0.98 for IgA reactivity to both Rv0629c and Rv2188c. IgG reactivity to Rv3223c resulted in an AUC of 0.96 and was markedly higher compared to TST nonconverters. We also identified several differences in metabolite profiles, including changes in biomarkers of inflammation, fatty acid metabolism, and bile acids. Pantothenate (vitamin B5) was significantly increased in TST nonconverters compared to converters at baseline (q = 0.0060). CONCLUSIONS: These data provide new insights into the early protective response to Mtb infection and possible avenues to interfere with Mtb infection, including vitamin B5 supplementation.Analysis of blood from highly exposed household contacts from The Gambia who never develop latent Mycobacterium tuberculosis infection shows distinct transcriptomic, antibody, and metabolomic profiles compared to those who develop latent tuberculosis infection but prior to any signs of infection.

Analysis of cellular and soluble profiles in QuantiFERON nonconverters, converters, and reverters in the Gambia.

BACKGROUND: Tuberculosis (TB) is the leading cause of death from a single infectious agent worldwide. The immune system is capable of clearing the pathogen before establishment of latent infection but the mechanisms for this are not yet understood. METHODS: This study analysed highly exposed household contacts (HHC) of TB index cases who were categorised according to QuantiFERON (QFT) results at recruitment and 6 months. Seventeen (17) QFT nonconverters, 14 QFT converters, 18 QFT reverters and 18 latent TB infection (LTBI) were analysed. Supernatants generated following QFT stimulation at both time-points were analysed using a 64-plex cytokine array. Flow cytometry was performed on QFT converters and nonconverters at baseline only. RESULTS: Interleukin-2 (IL-2), IL-5, IL-13, APRIL, IL-17A, IP-10, MIP-1ß, sIL-6rb, OPN, and sTNFR2 were all significantly higher in the QFT converters compared with nonconverters at baseline. Levels of interferon-α2 (IFN-α2) and IL-2 were significantly lower in QFT reverters compared with nonconverters at baseline. Analysis of Ag-specific IL-2 levels resulted in an area under the curve (AUC) of 0.93 (95% confidence interval [CI], 0.84-1.00) for QFT converters compared to nonconverters and an AUC of 0.80 (0.65-0.95) for QFT reverters compared with LTBI. Purified protein derivative (PPD)-specific CD4 + CD26 + IFN-γ + cells were significantly increased (P = .0007) in QFT nonconverters compared with QFT converters at baseline. CONCLUSIONS: Our results provide insight into the underlying mechanisms of resistance to sustained Mycobacterium tuberculosis infection.

Zinc as an adjunct therapy in the management of severe pneumonia among Gambian children: randomized controlled trial.

BACKGROUND: The benefit of zinc as an adjunct therapy for severe pneumonia is not established. We assessed the benefit of adjunct zinc therapy for severe pneumonia in children and determined whether the study children were zinc deficient. METHODS: This was a randomized, parallel group, double-blind, placebo-controlled trial with an allocation ratio of 1:1 conducted in children with severe pneumonia to evaluate the efficacy of daily zinc as an adjunct treatment in preventing 'treatment failure' (presence of any sign of severe pneumonia) on day-5 and day-10 and in reducing the time to resolution of signs of severe pneumonia. Six hundred and four children 2-59 months of age presenting with severe pneumonia at six urban and rural health care facilities in The Gambia were individually randomised to receive placebo (n = 301) or zinc (n = 303) for seven days. To determine if the study children were zinc deficient, supplementation was continued in a randomly selected subgroup of 121 children from each arm for six months post-enrolment, and height-gain, nutritional status, plasma zinc concentrations, and immune competence were compared. RESULTS: Percentage of treatment failure were similar in placebo and zinc arms both on day 5 (14.0% vs 14.1%) and day 10 (5.2% vs 5.9%). The time to recovery from lower chest wall indrawing and sternal retraction was longer in the placebo compared to zinc arm (24.4 vs 23.0 hours; P = 0.011 and 18.7 vs 11.0 hours; P = 0.006 respectively). The time to resolution for all respiratory symptoms of severity was not significantly different between placebo and zinc arms (42.3 vs 30.9 hours respectively; P = 0.242). In the six months follow-up sub-group, there was no significant difference in height gain, height-for-age and weight-for-height Z-scores, mid upper arm circumference, plasma zinc concentrations, and anergy at six months post-enrolment. CONCLUSIONS: In this population, zinc given as an adjunct treatment for severe pneumonia showed no benefit in treatment failure rates, or clinically important benefit in time to recovery from respiratory symptoms and showed marginal benefit in rapidity of resolution of some signs of severity. This finding does not support routine use of zinc as an adjunct treatment in severe pneumonia in generally zinc replete children. TRIAL REGISTRATION: ISRCTN33548493.

Four-Gene Pan-African Blood Signature Predicts Progression to Tuberculosis.

Rationale: Contacts of patients with tuberculosis (TB) constitute an important target population for preventive measures because they are at high risk of infection with Mycobacterium tuberculosis and progression to disease.Objectives: We investigated biosignatures with predictive ability for incident TB.Methods: In a case-control study nested within the Grand Challenges 6-74 longitudinal HIV-negative African cohort of exposed household contacts, we employed RNA sequencing, PCR, and the pair ratio algorithm in a training/test set approach. Overall, 79 progressors who developed TB between 3 and 24 months after diagnosis of index case and 328 matched nonprogressors who remained healthy during 24 months of follow-up were investigated.Measurements and Main Results: A four-transcript signature derived from samples in a South African and Gambian training set predicted progression up to two years before onset of disease in blinded test set samples from South Africa, the Gambia, and Ethiopia with little population-associated variability, and it was also validated in an external cohort of South African adolescents with latent M. tuberculosis infection. By contrast, published diagnostic or prognostic TB signatures were predicted in samples from some but not all three countries, indicating site-specific variability. Post hoc meta-analysis identified a single gene pair, C1QC/TRAV27 (complement C1q C-chain / T-cell receptor-α variable gene 27) that would consistently predict TB progression in household contacts from multiple African sites but not in infected adolescents without known recent exposure events.Conclusions: Collectively, we developed a simple whole blood-based PCR test to predict TB in recently exposed household contacts from diverse African populations. This test has potential for implementation in national TB contact investigation programs.

Functional and Phenotypic Changes of Natural Killer Cells in Whole Blood during Mycobacterium tuberculosis Infection and Disease.

Tuberculosis (TB) is still a global health concern, especially in resource-poor countries such as The Gambia. Defining protective immunity to TB is challenging: its pathogenesis is complex and involves several cellular components of the immune system. Recent works in vaccine development suggest important roles of the innate immunity in natural protection to TB, including natural killer (NK) cells. NK cells mediate cellular cytotoxicity and cytokine signaling in response to Mycobacterium tuberculosis (Mtb). NK cells can display specific memory-type markers to previous antigen exposure; thus, bridging innate and adaptive immunity. However, major knowledge gaps exist on the contribution of NK cells in protection against Mtb infection or TB. We performed a cross-sectional assessment of NK cells phenotype and function in four distinct groups of individuals: TB cases pre-treatment (n = 20) and post-treatment (n = 19), and household contacts with positive (n = 9) or negative (n = 18) tuberculin skin test (TST). While NK cells frequencies were similar between all groups, significant decreases in interferon-γ expression and degranulation were observed in NK cells from TB cases pre-treatment compared to post-treatment. Conversely, CD57 expression, a marker of advanced NK cells differentiation, was significantly lower in cases post-treatment compared to pre-treatment. Finally, NKG2C, an activation and imprinted-NK memory marker, was significantly increased in TST+ (latently infected) compared to TB cases pre-treatment and TST- (uninfected) individuals. The results of this study provide valuable insights into the role of NK cells in Mtb infection and TB disease, demonstrating potential markers for distinguishing between infection states and monitoring of TB treatment response.