Monitoring the COVID-19 epidemic in the context of widespread local transmission.

Coronavirus disease 2019 (COVID-19) is a novel viral disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which was first detected in Wuhan, China, in December, 2019.1 Given the fast spread, the severity of disease, the increasing number of cases outside China, and the number of affected countries, WHO declared the rapid spread of SARS-CoV-2 a pandemic on March 11, 2020.2 The availability of reliable surveillance platforms is crucial to monitor the COVID-19 epidemic in a timely manner and to respond with adequate control measures. Since the beginning of the outbreak, different countries have used different testing approaches and criteria, depending on their resources and capacity

Correlation of Xpert MTB/RIF with measures to assess Mycobacterium tuberculosis bacillary burden in high HIV burden areas of Southern Africa.

Traditionally, smear microscopy has been used as a point-of-care measure of bacillary burden in tuberculosis patients to inform infection control and contact tracing. Xpert MTB/RIF has the potential to replace smear. However, data to support the use of its quantitative output [cycle threshold (CT)] as an alternate point-of-care measure of bacillary burden are limited. This study assessed the correlation (Spearman's) between CT, smear, culture time-to-positivity (TTP), and clinical factors in patients with Xpert-positive sputum from Mozambique (n = 238) and South Africa (n = 462). Mean CT and smear grade correlated well (ρ0.72); compared to TTP and smear (ρ0.61); and mean CT and TTP (ρ0.50). In multivariate analyses, lower CT (higher bacillary load) was associated with negative HIV serostatus and low BMI. A smear positivity rule-out (95% sensitivity) CT cut-off of 28.0 was identified, with 54.1% specificity, 2.07 positive likelihood ratio, 0.09 negative likelihood ratio and 79.0% correctly classified. Cut-offs were higher for HIV positive compared to HIV negative individuals for any set sensitivity level. This study suggests Xpert CT values correlate well with smear, both in HIV positive and negative individuals, and that CT cut-offs might be broadly applicable to multiple settings. Studies to directly assess the association of CT with infectiousness are needed

Point of care diagnostics for tuberculosis

The goals of the End TB strategy, which aims to achieve a 90% reduction in tuberculosis (TB) incidence and a 95% reduction in TB mortality by 2035, will not be achieved without new tools to fight TB. These include improved point of care (POC) diagnostic tests that are meant to be delivered at the most decentralised levels of care where the patients make the initial contact with the health system, as well as within the community. These tests should be able to be performed on an easily accessible sample and provide results in a timely manner, allowing a quick treatment turnaround time of a few minutes or hours (in a single clinical encounter), hence avoiding patient loss-to-follow-up. There have been exciting developments in recent years, including the WHO endorsement of Xpert MTB/RIF, Xpert MTB/RIF Ultra, loop-mediated isothermal amplification (TB-LAMP) and lateral flow lipoarabinomannan (LAM). However, these tests have limitations that must be overcome before they can be optimally applied at the POC. Furthermore, worrying short- to medium-term gaps exist in the POC diagnostic test development pipeline. Thus, not only is better implementation of existing tools and algorithms needed, but new research is required to develop new POC tests that allow the TB community to truly make an impact and find the ‘‘missed TB cases’’

Improved detection and management of advanced HIV disease through a community adult TB‐contact tracing intervention with same‐day provision of the WHO‐recommended package of care including ART initiation in a rural district of Mozambique

Introduction: AIDS-mortality remains unacceptably high in sub-Saharan Africa, largely driven by advanced HIV disease (AHD). We nested a study in an existing tuberculosis (TB) contact-tracing intervention (Xpatial-TB). The aim was to assess the burden of AHD among high-risk people living with HIV (PLHIV) identified and to evaluate the provision of the WHO-recommended package of care to this population. Methods: All PLHIV ≥14 years old identified between June and December 2018 in Manhiça District by Xpatial-TB were offered to participate in the study if ART naïve or had suboptimal ART adherence. Consenting individuals were screened for AHD. Patients with AHD (CD4 < 200 cells/μL or WHO stage 3 or 4) were offered a package of interventions in a single visit, including testing for cryptococcal antigen (CrAg) and TB-lipoarabinomannan (TB-LAM), prophylaxis and treatment for opportunistic infections, adherence support or accelerated ART initiation. We collected information on follow-up visits carried out under routine programmatic conditions for six months. Results: A total of 2881 adults were identified in the Xpatial TB-contact intervention. Overall, 23% (673/2881) were HIV positive, including 351 TB index (64.2%) and 322 TB contacts (13.8%). Overall, 159/673 PLHIV (24%) were ART naïve or had suboptimal ART adherence, of whom 155 (97%, 124 TB index and 31 TB-contacts) consented to the study and were screened for AHD. Seventy percent of TB index-patients (87/124) and 16% of TB contacts (5/31) had CD4 < 200 cells/µL. Four (13%) of the TB contacts had TB, giving an overall AHD prevalence among TB contacts of 29% (9/31). Serum-CrAg was positive in 4.6% (4/87) of TB-index patients and in zero TB contacts. All ART naïve TB contacts without TB initiated ART within 48 hours of HIV diagnosis. Among TB cases, ART timing was tailored to the presence of TB and cryptococcosis. Six-month mortality was 21% among TB-index cases and zero in TB contacts. Conclusions: A TB contact-tracing outreach intervention identified undiagnosed HIV and AHD in TB patients and their contacts, undiagnosed cryptococcosis among TB patients, and resulted in an adequate provision of the WHO-recommended package of care in this rural Mozambican population. Same-day and accelerated ART initiation was feasible and safe in this population including among those with AHD

Mortality and risk of tuberculosis among people living with HIV in whom TB was initially ruled out

Tuberculosis (TB) misdiagnosis remains a public health concern, especially among people living with HIV (PLHIV), given the high mortality associated with missed TB diagnoses. The main objective of this study was to describe the\xC2\xA0all-cause mortality, TB incidence rates and their\xC2\xA0associated risk factors in a cohort of PLHIV with presumptive TB in whom TB was initially ruled out. We retrospectively followed a cohort of PLHIV with presumptive TB over a 2\xC2\xA0year-period in a rural district in Southern Mozambique. During the study period 382 PLHIV were followed-up. Mortality rate was 6.8/100 person-years (PYs) (95% CI 5.2-9.2) and TB incidence rate was 5.4/100 PYs (95% CI 3.9-7.5). Thirty-six percent of deaths and 43% of TB incident cases occurred in the first 12\xC2\xA0months of the follow up. Mortality and TB incidence rates in the 2-year period after TB was initially ruled out was very high. The\xC2\xA0TB diagnostic work-up and linkage to HIV\xC2\xA0care should be strengthened to decrease TB burden and all-cause mortality among PLHIV with presumptive TB

IP-10 Kinetics in the First Week of Therapy are Strongly Associated with Bacteriological Confirmation of Tuberculosis Diagnosis in HIV-Infected Patients

Simple effective tools to monitor the long treatment of tuberculosis (TB) are lacking. Easily measured host derived biomarkers have been identified but need to be validated in larger studies and different population groups. Here we investigate the early response in IP-10 levels (between day 0 and day 7 of TB therapy) to identify bacteriological status at diagnosis among 127 HIV-infected patients starting TB treatment. All participants were then classified as responding or not responding to treatment blindly using a previously described IP-10 kinetic algorithm. There were 77 bacteriologically confirmed cases and 41 Xpert MTB/RIF® and culture negative cases. Most participants had a measurable decline in IP-10 during the first 7 days of therapy. Bacteriologically confirmed cases were more likely to have high IP-10 levels at D0 and had a steeper decline than clinically diagnosed cases (mean decline difference 2231 pg/dl, 95% CI: 897-3566, p = 0.0013). Bacteriologically confirmed cases were more likely to have a measurable decline in IP-10 at day 7 than clinically diagnosed cases (48/77 (62.3%) vs 13/41 (31.7%), p < 0.001). This study confirms the association between a decrease in IP-10 levels during the first week of treatment and a bacteriological confirmation at diagnosis in a large cohort of HIV positive patients

End-point definition and trial design to advance tuberculosis vaccine development.

Tuberculosis (TB) remains a leading infectious cause of death worldwide and the coronavirus disease 2019 pandemic has negatively impacted the global TB burden of disease indicators. If the targets of TB mortality and incidence reduction set by the international community are to be met, new more effective adult and adolescent TB vaccines are urgently needed. There are several new vaccine candidates at different stages of clinical development. Given the limited funding for vaccine development, it is crucial that trial designs are as efficient as possible. Prevention of infection (POI) approaches offer an attractive opportunity to accelerate new candidate vaccines to advance into large and expensive prevention of disease (POD) efficacy trials. However, POI approaches are limited by imperfect current tools to measure Mycobacterium tuberculosis infection end-points. POD trials need to carefully consider the type and number of microbiological tests that define TB disease and, if efficacy against subclinical (asymptomatic) TB disease is to be tested, POD trials need to explore how best to define and measure this form of TB. Prevention of recurrence trials are an alternative approach to generate proof of concept for efficacy, but optimal timing of vaccination relative to treatment must still be explored. Novel and efficient approaches to efficacy trial design, in addition to an increasing number of candidates entering phase 2-3 trials, would accelerate the long-standing quest for a new TB vaccine

Unravelling the population structure and transmission patterns of Mycobacterium tuberculosis in Mozambique, a high TB/HIV burden country

Genomic studies of Mycobacterium tuberculosis complex (MTBC) might shed light on the dynamics of its transmission, especially in high-burden settings, where recent outbreaks are embedded in the complex natural history of the disease. We applied Whole-genome sequencing (WGS) to characterize the local population of MTBC, unravel potential transmission links and evaluate associations with host and pathogen factors. Methods A one-year prospective study was conducted in Mozambique, a high HIV/TB burden country. WGS was applied to 295 positive cultures. We combined phylogenetic, geographical and clustering analysis, and investigated associations between risk factors of transmission. Findings A significant high proportion of strains were in recent transmission (45.5%). We fully characterized MTBC isolates by using phylogenetic approaches and dating evaluation. We found two likely endemic clades, comprised of 67 strains, belonging to L1.2, dating from the late XIX century and associated with recent spread among PLHIV. Interpretation Our results unveil the population structure of MTBC in our setting. The clustering analysis revealed an unexpected pattern of spread and high rates of progression, suggesting the failure of control measures. The long-term presence of local strains in Mozambique, which were responsible for large transmission among HIV/TB coinfected patients, hint at possible coevolution with sympatric host populations and challenge the role of HIV in TB transmission.Ministry of Enterprise and Knowledge (Government of Catalonia & European Social Fund, AGAUR fellowship); European Research Council (ERC) European Union’s Horizon 2020.N

Host-Directed Therapies for tackling Multi-Drug Resistant TB – learning from the Pasteur-Bechamp debates

Tuberculosis (TB) remains a global emergency causing an estimated 1.5 million deaths annually. For several decades the major focus of TB treatment has been on antibiotic development targeting Mycobacterium tuberculosis (M.tb). The lengthy TB treatment duration and poor treatment outcomes associated with multi-drug resistant TB (MDR-TB) are of major concern. The sparse new TB drug pipeline and widespread emergence of MDR-TB signal an urgent need for more innovative interventions to improve treatment outcomes. Building on the historical Pasteur-Bechamp debates on the role of the ‘microbe’ versus the ‘host internal milieu’ in disease causation, we make the case for parallel investments into host-directed therapies (HDTs). A range of potential HDTs are now available which require evaluation in randomized controlled clinical trials as adjunct therapies for shortening the duration of TB therapy and improving treatment outcomes for drug-susceptible TB and MDR-TB. Funder initiatives that may enable further research into HDTs are described