Digital health solutions and integrated COVID-19 and TB services to help recover TB care and prevention services in the COVID-19 pandemic: A descriptive study in four high TB burden countries.

BACKGROUND: The measures undertaken to control COVID-19 have disrupted many platforms including tuberculosis (TB) healthcare services. Consequently, declines in TB notifications have been observed in various countries. We visualized changes over time in TB and SARS-CoV-2 infection notifications and reported on country-specific strategies to retain TB care and prevention services in Kyrgyzstan, Nigeria, Tanzania, and Vietnam. METHODS: We collected and visualized quarterly, retrospective, and country-specific data (Quarter (Q) 1 2018- Q1 2021) on SARS-CoV-2 infection and TB notifications. Additionally, we conducted a country-specific landscape assessment on COVID-19 measures, including lockdowns, operational level strategy of TB care and prevention services, and strategies employed to recover and retain those services. We used negative binomial regression models to assess the association between the installation of COVID-19 measures and changes in TB notifications. RESULTS: TB notifications declined in Kyrgyzstan and Vietnam, and (slightly) increased in Nigeria and Tanzania. The changes in TB notifications were associated with the installation of various COVID-19 prevention measures for Kyrgyzstan and Vietnam (declines) and Nigeria (increases). All countries reported reduced TB screening and testing activities. Countries reported the following strategies to retain TB prevention and care services: digital solutions for treatment adherence support, capacity building, and monitor & evaluation activities; adjustment in medication supply/delivery & quantity, including home delivery, pick up points, and month supply; integrated TB/COVID-19 screening & diagnostic platform; and the use of community health care workers. CONCLUSION: Following the COVID-19 pandemic, we did not observe consistent changes in TB notifications across countries. However, all countries reported lower operating levels of TB prevention and care services. Digital health solutions, community-based interventions, and the integration of COVID-19 and TB testing services were employed to recover and retain those services.

Newborn screening for sickle cell disease: an innovative pilot program to improve child survival in Dar es Salaam, Tanzania.

BACKGROUND: Sickle cell disease (SCD) is a recognized cause of childhood mortality. Tanzania has the fifth highest incidence of SCD (with an estimated 11 000 SCD annual births) worldwide. Although newborn screening (NBS) for SCD and comprehensive healthcare have been shown to reduce under-5 mortality by up to 94% in high-income countries such as the USA, no country in Africa has maintained NBS for SCD as a national health program. The aims of this program were to establish and evaluate NBS-SCD as a health intervention in Tanzania and to determine the birth prevalence of SCD. METHODS: Muhimbili University of Health and Allied Sciences conducted NBS for SCD from January 2015 to November 2016. Dried blood spot samples were collected and tested for SCD using isoelectric focusing. RESULTS: Screening was conducted on 3981 newborns. Thirty-one (0.8%) babies had SCD, 505 (12.6%) had sickle cell trait and 26 (0.7%) had other hemoglobinopathies. Twenty-eight (90.3%) of the 31 newborns with SCD were enrolled for comprehensive healthcare. CONCLUSIONS: This is the first report on NBS as a health program for SCD in Tanzania. The SCD birth prevalence of 8 per 1000 births is of public health significance. It is therefore important to conduct NBS for SCD with enrollment into a comprehensive care program.

Increased mortality associated with treated active tuberculosis in HIV-infected adults in Tanzania.

Active tuberculosis (TB) among HIV-infected patients, even when successfully treated, may be associated with excess mortality. We conducted a prospective cohort study nested in a randomized TB vaccine trial to compare mortality between HIV-infected patients diagnosed and treated for TB (TB, n = 77) and HIV-infected patients within the same CD4 range, who were not diagnosed with or treated for active TB (non-TB, n = 308) in the period 2001-2008. Only twenty four subjects (6%) were on antiretroviral therapy at the beginning of this study. After accounting for covariate effects including use of antiretroviral therapy, isoniazid preventive therapy, and receipt of vaccine, we found a four-fold increase in mortality in TB patients compared with non-TB patients (adjusted Hazard Ratio 4.61; 95% Confidence Interval (CI): 1.63, 13.05). These findings suggest that treatment for TB alone is not sufficient to avert the excess mortality associated with HIV-related TB and that prevention of TB may provide a mortality benefit.

Recurrent tuberculosis risk among HIV-infected adults in Tanzania with prior active tuberculosis.

BACKGROUND: Active tuberculosis is common among human immunodeficiency virus (HIV)-infected persons living in tuberculosis-endemic areas, but the hazard of subsequent tuberculosis disease has not been quantified in a single prospective cohort. METHODS: Among HIV-infected, BCG-immunized adults with CD4 counts ≥200 cells/µL who received placebo in the DarDar tuberculosis vaccine trial in Tanzania, we compared the prospective risk of active tuberculosis between subjects who did and who did not report prior active tuberculosis. All subjects with a positive tuberculin skin test without prior active tuberculosis were offered isoniazid preventive treatment. Definite or probable tuberculosis was diagnosed during active follow-up using rigorous published criteria. RESULTS: We diagnosed 52 cases of definite and 92 cases of definite/probable tuberculosis among 979 subjects during a median follow-up of 3.2 years. Among the 80 subjects who reported prior active tuberculosis, 11 (13.8%) subsequently developed definite tuberculosis and 17 (21.3%) developed definite/probable tuberculosis, compared with 41 (4.6%) and 75 (8.3%), respectively, of 899 subjects without prior active tuberculosis (definite tuberculosis risk ratio [RR], 3.01; 95% confidence interval [CI], 1.61-5.63, P < .001; definite/probable tuberculosis RR, 2.55; 95% CI, 1.59-4.09, P < .001). In a Cox regression model adjusting for age, CD4 count, and isoniazid receipt, subjects with prior active tuberculosis had substantially greater hazard of subsequent definite tuberculosis (hazard radio [HR], 3.69; 95% CI, 1.79-7.63, P < .001) and definite/probable tuberculosis (HR, 2.78; 95% CI, 1.58-4.87, P < .001). CONCLUSIONS: Compared to subjects without prior tuberculosis, the hazard of active tuberculosis is increased 3-fold among HIV-infected adults with prior active tuberculosis. Clinical Trials Registration. NCT0052195.

Molecular epidemiology of HIV-associated tuberculosis in Dar es Salaam, Tanzania: strain predominance, clustering, and polyclonal disease.

Molecular typing of Mycobacterium tuberculosis can be used to elucidate the epidemiology of tuberculosis, including the rates of clustering, the frequency of polyclonal disease, and the distribution of genotypic families. We performed IS6110 typing and spoligotyping on M. tuberculosis strains isolated from HIV-infected subjects at baseline or during follow-up in the DarDar Trial in Tanzania and on selected community isolates. Clustering occurred in 203 (74%) of 275 subjects: 124 (80%) of 155 HIV-infected subjects with baseline isolates, 56 (69%) of 81 HIV-infected subjects with endpoint isolates, and 23 (59%) of 39 community controls. Overall, 113 (41%) subjects had an isolate representing the East Indian "GD" family. The rate of clustering was similar among vaccine and placebo recipients and among subjects with or without cellular immune responses to mycobacterial antigens. Polyclonal disease was detected in 6 (43%) of 14 patients with multiple specimens typed. Most cases of HIV-associated tuberculosis among subjects from this study in Dar es Salaam resulted from recently acquired infection. Polyclonal infection was detected and isolates representing the East Indian GD strain family were the most common.

Maintenance of Sensitivity of the T-SPOT.TB Assay after Overnight Storage of Blood Samples, Dar es Salaam, Tanzania.

Background. T-SPOT.TB is an interferon gamma release assay for detecting Mycobacterium tuberculosis infection. The requirement to process within 8 hours is constraining, deters use, and leads to invalid results. Addition of T Cell Xtend reagent may allow delayed processing, but has not been extensively field tested. Design. Consecutive AFB smear positive adult tuberculosis patients were prospectively recruited in Dar es Salaam, Tanzania. Patients provided a medical history, 1-3 sputum samples for culture and 1 blood sample which was transported to the laboratory under temperature-controlled conditions. After overnight storage, 25 µL of T Cell Xtend reagent was added per mL of blood, and the sample was tested using T-SPOT.TB. Results. 143 patients were enrolled: 57 patients were excluded because temperature control was not maintained, 19 patients were excluded due to red blood cell contamination, and one did not provide a sputum sample for culture. Among 66 evaluable patients, overall agreement between T-SPOT.TB and culture was 95.4% (95%CI; 87.1-99.0%) with Kappa value 0.548. Sensitivity of T-SPOT.TB when using T Cell Xtend reagent was 96.8% (95%CI; 88.8-99.6%). Conclusions. When T Cell Xtend reagent is added to specimens held overnight at recommended temperatures, T-SPOT.TB is as sensitive as the standard assay in patients with tuberculosis.

Polyantigenic interferon-γ responses are associated with protection from TB among HIV-infected adults with childhood BCG immunization.

BACKGROUND: Surrogate immunologic markers for natural and vaccine-mediated protection against tuberculosis (TB) have not been identified. METHODS: HIV-infected adults with childhood BCG immunization entering the placebo arm of the DarDar TB vaccine trial in Dar es Salaam, Tanzania, were assessed for interferon gamma (IFN-γ) responses to three mycobacterial antigen preparations--secreted Mycobacterium tuberculosis antigens 85 (Ag85), early secretory antigenic target 6 (ESAT-6) and polyantigenic whole cell lysate (WCL). We investigated the association between the number of detectable IFN-γ responses at baseline and the subsequent risk of HIV-associated TB. RESULTS: During a median follow-up of 3.3 years, 92 (9.4%) of 979 placebo recipients developed TB. The incidence of TB was 14% in subjects with no detectable baseline IFN-γ responses vs. 8% in subjects with response to polyantigenic WCL (P = 0.028). Concomitant responses to secreted antigens were associated with further reduction in the incidence of HIV-associated TB. Overall the percentage of subjects with 0, 1, 2 and 3 baseline IFN-γ responses to mycobacterial preparations who developed HIV-associated TB was 14%, 8%, 7% and 4%, respectively (P = 0.004). In a multivariate Cox regression model, the hazard of developing HIV-associated TB was 46% lower with each increment in the number of detectable baseline IFN-γ responses (P<0.001). CONCLUSIONS: Among HIV-infected adults who received BCG in childhood and live in a TB-endemic country, polyantigenic IFN-γ responses are associated with decreased risk of subsequent HIV-associated TB. TRIAL REGISTRATION: ClinicalTrials.gov NCT0052195.

Interferon γ responses to mycobacterial antigens protect against subsequent HIV-associated tuberculosis.

BACKGROUND: The cellular immune responses that protect against tuberculosis have not been identified. METHODS: We assessed baseline interferon γ (IFN­Î³) and lymphocyte proliferation assay (LPA) responses to antigen 85 (Ag85), early secretory antigenic target 6 (ESAT­6), and Mycobacterium tuberculosis whole cell lysate (WCL) in human immunodeficiency virus (HIV)-infected and bacille Calmette­Guérin (BCG)-immunized adults with CD4 cell counts of >or= 200 cells/µL who received placebo in the DarDar tuberculosis vaccine trial in Tanzania. Subjects were followed prospectively to diagnose definite or probable tuberculosis. RESULTS: Tuberculosis was diagnosed in 92 of 979 subjects during a mean follow­up of 3.2 years. The relative risk of tuberculosis among subjects with positive IFN­Î³ responses to Ag85 was 0.51 (95% confidence interval [CI], 0.26-0.99; P = .049), to ESAT­6 was 0.44 (95% CI, 0.23-0.85; P = .004), and to WCL was 0.67 (95% CI, 0.49-0.88; P = .002). The relative risk of tuberculosis was not significantly associated with baseline LPA responses. In a multivariate Cox regression model, subjects with IFN­Î³ responses to ESAT­6 and WCL had a lower hazard of developing tuberculosis, with a hazard ratio for ESAT­6 of 0.35 (95% CI, 0.16­0.77; P = .009) and a hazard ratio for WCL of 0.30 (95% CI, 0.16-0.56; P < .001). CONCLUSIONS: Baseline IFN­Î³ responses to ESAT-6 and WCL were associated with protection from subsequent tuberculosis among HIV-infected subjects with childhood BCG immunization in a region of high tuberculosis prevalence. Trial registration. ClinicalTrials.gov identifier: NCT00052195.

Immunogenicity of a protective whole cell mycobacterial vaccine in HIV-infected adults: a phase III study in Tanzania.

Preventive immunization with whole inactivated Mycobacterium vaccae (MV) confers protection against HIV-associated tuberculosis (TB) in BCG-immunized adults with CD4 counts ≥200 cells/µl. We evaluated the immunogenicity of MV in the 2013 subjects of the phase III DarDarTrial using an interferon gamma (IFN-γ) enzyme linked immunosorbent assay (ELISA), tritiated thymidine lymphocyte proliferation assay (LPA) and an ELISA for antibodies to the TB glycolipid lipoarabinomannan (LAM). MV immunization boosts IFN-γ and LPA responses to MV sonicate, and antibody responses to LAM. Post-immunization immune responses to MV correlated with baseline clinical factors, but the responses did not predict protection from HIV-associated TB.

Prevention of tuberculosis in Bacille Calmette-Guérin-primed, HIV-infected adults boosted with an inactivated whole-cell mycobacterial vaccine.

OBJECTIVE: To determine whether a multiple-dose series of an inactivated whole cell mycobacterial vaccine, Mycobacterium vaccae, can prevent HIV-associated tuberculosis. DESIGN AND METHODS: The DarDar trial was a randomized, placebo-controlled, double-blind trial. The study was carried in an outpatient facility in Dar es Salaam, Tanzania. HIV-infected patients with CD4 cell counts of at least 200 cells/microl and a Bacille Calmette-Guérin scar were chosen for the study. The intervention was carried out by random 1:1 assignment to five intradermal doses of M. vaccae or placebo. Tuberculin skin tests were performed, and patients with reactions of at least 5 mm were administered isoniazid for 6 months. The main outcome measures were disseminated (primary endpoint), definite, and probable tuberculosis (secondary endpoints). RESULTS: Two thousand thirteen individuals were randomized (1006 to M. vaccae, 1007 to placebo) and followed every 3 months for a median of 3.3 years. The trial was terminated early because of slow accrual of cases of disseminated tuberculosis and significant protection against definite tuberculosis. Hazard ratios were disseminated tuberculosis 0.52 (95% confidence interval 0.21-1.34; seven cases in M. vaccae, 13 cases in placebo; log-rank P = 0.16), definite tuberculosis 0.61 (95% confidence interval 0.39-0.96; 33 cases in M. vaccae, 52 cases in placebo; P = 0.03), and probable tuberculosis 1.17 (95% confidence interval 0.76-1.80; 48 cases in M. vaccae, 40 cases in placebo; P = 0.46). Immunization was well tolerated, with no adverse effect on CD4 cell count or HIV viral load, and no increase in the rate of serious adverse events. CONCLUSION: Administration of a multiple-dose series of M. vaccae to HIV-infected adults with childhood Bacille Calmette-Guérin immunization is safe and is associated with significant protection against definite tuberculosis. These results provide evidence that immunization with a whole cell mycobacterial vaccine is a viable strategy for the prevention of HIV-associated tuberculosis.

Lymphocyte proliferation to mycobacterial antigens is detectable across a spectrum of HIV-associated tuberculosis.

BACKGROUND: Identifying novel TB diagnostics is a major public health priority. We explored the diagnostic characteristics of antimycobacterial lymphocyte proliferation assays (LPA) in HIV-infected subjects with latent or active TB. METHODS: HIV-infected subjects with bacille Calmette Guérin (BCG) scars and CD4 counts > or = 200 cells/mm(3) entering a TB booster vaccine trial in Tanzania had baseline in vivo and in vitro immune tests performed: tuberculin skin tests (TST), LPA and five day assays of interferon gamma (IFN-gamma) release. Assay antigens were early secreted antigenic target 6 (ESAT-6), antigen 85 (Ag85), and Mycobacterium tuberculosis whole cell lysate (WCL). Subjects were screened for active TB at enrollment by history, exam, sputum smear and culture. We compared antimycobacterial immune responses between subjects with and without latent or active TB at enrollment. RESULTS: Among 1885 subjects screened, 635 had latent TB and 13 had active TB. Subjects with latent TB were more likely than subjects without TB to have LPA responses to ESAT-6 (13.2% vs. 5.5%, P < 0.0001), Ag85 (18.7% vs. 3.1%, P < 0.0001), and WCL (45.7% vs. 17.1%, P < 0.0001). Subjects with active TB also were more likely than those without active TB to have detectable LPA responses to ESAT-6 (38.5% vs. 8.1%, P = 0.0001), Ag85 (46.2% vs. 8.5%, P < 0.0001), and WCL (61.5% vs. 27.0%, P = 0.0053). In subjects with a positive TST, LPA responses to ESAT-6, Ag85 and WCL were more common during active TB (p < 0.0001 for all tests). In diagnosing active TB, in vivo and in vitro tests of mycobacterial immune responses had sensitivity and specificity as follows: TST 84.6% and 65.5%, ESAT-6 LPA 38.5% and 92.0%, Ag85 LPA 46.2% and 91.5%, and WCL LPA 61.5% and 73.0%. Detectable LPA responses were more common in patients with higher CD4 counts, and higher HIV viral loads. CONCLUSION: Lymphoproliferative responses to mycobacteria are detectable during HIV-associated active TB, and are less sensitive but more specific than TST. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT00052195.

Basis for treatment of tuberculosis among HIV-infected patients in Tanzania: the role of chest x-ray and sputum culture.

BACKGROUND: Active tuberculosis (TB) is common among HIV-infected persons living in tuberculosis endemic countries, and screening for tuberculosis (TB) is recommended routinely. We sought to determine the role of chest x-ray and sputum culture in the decision to treat for presumptive TB using active case finding in a large cohort of HIV-infected patients. METHODS: Ambulatory HIV-positive subjects with CD4 counts > or = 200/mm3 entering a Phase III TB vaccine study in Tanzania were screened for TB with a physical examination, standard interview, CD4 count, chest x-ray (CXR), blood culture for TB, and three sputum samples for acid fast bacillus (AFB) smear and culture. RESULTS: Among 1176 subjects 136 (12%) were treated for presumptive TB. These patients were more frequently male than those without treatment (34% vs. 25%, respectively; p = 0.049) and had lower median CD4 counts (319/microL vs. 425/microL, respectively; p < .0001). Among the 136 patients treated for TB, 38 (28%) had microbiologic confirmation, including 13 (10%) who had a normal CXR and no symptoms. There were 58 (43%) treated patients in whom the only positive finding was an abnormal CXR. Blood cultures were negative in all patients. CONCLUSION: Many ambulatory HIV-infected patients with CD4 counts > or = 200/mm3 are treated for presumptive TB. Our data suggest that optimal detection requires comprehensive evaluation, including CXR and sputum culture on both symptomatic and asymptomatic subjects.

Sputum microscopy for the diagnosis of HIV-associated pulmonary tuberculosis in Tanzania.

BACKGROUND: In many resource poor settings only sputum microscopy is employed for the diagnosis of HIV-associated pulmonary tuberculosis; sputum culture may not be available. METHODS: We determined the diagnostic accuracy of sputum microscopy for active case finding of HIV-associated pulmonary tuberculosis using TB culture as the reference standard. RESULTS: 2216 potential subjects screened for a TB vaccine trial submitted 9454 expectorated sputum specimens: 212 (2.2%) were sputum culture positive for Mycobacterium tuberculosis (MTB), 31 (0.3%) for non-tuberculous mycobacteria, and 79 (0.8%) were contaminated. The overall sensitivity of sputum microscopy was 61.8% (131/212) and specificity 99.7% (9108/9132). Sputum microscopy sensitivity varied from 22.6% in specimens with < 20 colony forming units (CFU)/specimen to 94.2% in patients with > 100 CFU/specimen plus confluent growth. The incremental diagnostic value for sputum microscopy was 92.1%, 1.8% and 7.1% for the first, second and third specimens, respectively. The positive predictive value and negative predictive values for sputum microscopy were 84.5% and 99.1%, respectively. The likelihood ratio (LR) of a positive sputum microscopy was 235.1 (95% CI 155.8 - 354.8), while the LR of a negative test was 0.38 (95CI 0.32 - 0.45). The 212 positive sputum cultures for MTB represented 103 patients; sputum microscopy was positive for 57 (55.3%) of 103 patients. CONCLUSION: Sputum microscopy on 3 expectorated sputum specimens will only detect 55% of culture positive HIV-infected patients in active screening for pulmonary tuberculosis. Sensitivity is higher in patients with greater numbers of CFUs in the sputum. Culture is required for active case finding of HIV- associated pulmonary tuberculosis.

Baseline mycobacterial immune responses in HIV-infected adults primed with bacille Calmette-Guérin during childhood and entering a tuberculosis booster vaccine trial.

BACKGROUND: Most new tuberculosis vaccines will be administered as a booster to subjects primed with bacille Calmette-Guérin (BCG) during childhood. METHODS: We investigated in vivo and in vitro immune responses to mycobacteria in human immunodeficiency virus (HIV)-positive subjects in Tanzania primed with BCG during childhood and entering a tuberculosis booster vaccine trial. Tests included intradermal skin testing for Mycobacterium tuberculosis purified protein derivative (PPD) and Mycobacterium avium sensitin (MAS); lymphocyte proliferation assays and interferon (IFN)-gamma levels after stimulation with Mycobacterium vaccae sonicate (MVS), M. tuberculosis early secreted antigen (ESAT)-6, M. tuberculosis antigen 85 (Ag85), or M. tuberculosis whole-cell lysate (WCL); and determination of serum antibody to lipoarabinomannin (LAM). RESULTS: A total of 888 subjects with CD4 cell counts > or = 200 cells/mm3 were enrolled. PPD and MAS test results were positive in 34% and 30% of the subjects, respectively. Proliferative responses were detected as follows: MVS, 6%; Ag85, 24%; ESAT-6, 21%; and WCL, 59%. IFN-gamma responses were 2%, 6%, 12%, and 38%, respectively. LAM antibody was detected in 28% of the subjects. Subjects were more likely to have detectable proliferative and IFN-gamma responses if they had positive PPD test results or CD4 cell counts > or = 500 cells/mm3. Overall, 94% of the subjects had evidence of primed mycobacterial immune responses. CONCLUSION: Of HIV-positive BCG-immunized adults with CD4 cell counts > or = 200 cells/mm3 in Tanzania, 94% are primed for booster mycobacterial immunization.

High rates of clinical and subclinical tuberculosis among HIV-infected ambulatory subjects in Tanzania.

BACKGROUND: We sought to determine the prevalence of active tuberculosis among ambulatory HIV-infected persons in Tanzania with CD4 cell counts of > or =200 cells/mm3 and a bacille Calmette-Guerin vaccination scar. METHODS: Subjects who volunteered for a tuberculosis booster vaccine trial were screened for active tuberculosis by obtainment of a history, physical examination, chest radiography, sputum culture and acid fast bacillus (AFB) stain, and blood culture. All subjects underwent a tuberculin skin test (TST) and lymphocyte proliferation assays (LPAs) for detection of responses to mycobacterial antigens. RESULTS: Active tuberculosis was identified at baseline in 14 (15%) of the first 93 subjects who were enrolled: 10 (71%) had clinical tuberculosis (symptoms or chest radiograph findings), and 4 (29%) had subclinical tuberculosis (positive sputum AFB stain or culture results but no symptoms or chest radiograph findings). An additional 6 subjects with subclinical tuberculosis were identified subsequently. The 10 subjects with subclinical tuberculosis included 3 with positive sputum AFB stains results and 7 who were only identified by a positive sputum culture result. Compared with subjects who did not have tuberculosis, the 10 subjects with subclinical tuberculosis were more likely to have peripheral lymphadenopathy, positive TST results, and elevated LPA responses to early secreted antigenic target-6 (ESAT). Eight of 10 patients had received isoniazid because of a positive TST result before active tuberculosis was recognized. CONCLUSIONS: Clinical and subclinical tuberculosis are common among ambulatory HIV-infected persons, and some cases can only be identified by sputum culture. World Health Organization guidelines for screening for latent tuberculosis before treatment do not recommend sputum culture and, therefore, may fail to identify a substantial number of HIV-infected persons with subclinical, active tuberculosis.