Multidrug-resistant tuberculosis

Overview of Immune Response During SARS-CoV-2 Infection: Lessons From the Past

After the 1918 flu pandemic, the world is again facing a similar situation. However, the advancement in medical science has made it possible to identify that the novel infectious agent is from the coronavirus family. Rapid genome sequencing by various groups helped in identifying the structure and function of the virus, its immunogenicity in diverse populations, and potential preventive measures. Coronavirus attacks the respiratory system, causing pneumonia and lymphopenia in infected individuals. Viral components like spike and nucleocapsid proteins trigger an immune response in the host to eliminate the virus. These viral antigens can be either recognized by the B cells or presented by MHC complexes to the T cells, resulting in antibody production, increased cytokine secretion, and cytolytic activity in the acute phase of infection. Genetic polymorphism in MHC enables it to present some of the T cell epitopes very well over the other MHC alleles. The association of MHC alleles and its downregulated expression has been correlated with disease severity against influenza and coronaviruses. Studies have reported that infected individuals can, after recovery, induce strong protective responses by generating a memory T-cell pool against SARS-CoV and MERS-CoV. These memory T cells were not persistent in the long term and, upon reactivation, caused local damage due to cross-reactivity. So far, the reports suggest that SARS-CoV-2, which is highly contagious, shows related symptoms in three different stages and develops an exhaustive T-cell pool at higher loads of viral infection. As there are no specific treatments available for this novel coronavirus, numerous small molecular drugs that are being used for the treatment of diseases like SARS, MERS, HIV, ebola, malaria, and tuberculosis are being given to COVID-19 patients, and clinical trials for many such drugs have already begun. A classical immunotherapy of convalescent plasma transfusion from recovered patients has also been initiated for the neutralization of viremia in terminally ill COVID-19 patients. Due to the limitations of plasma transfusion, researchers are now focusing on developing neutralizing antibodies against virus particles along with immuno-modulation of cytokines like IL-6, Type I interferons (IFNs), and TNF-α that could help in combating the infection. This review highlights the similarities of the coronaviruses that caused SARS and MERS to the novel SARS-CoV-2 in relation to their pathogenicity and immunogenicity and also focuses on various treatment strategies that could be employed for curing COVID-19.

Cost of multi drug resistance tuberculosis in Germany

OBJECTIVES

4220 new cases of tuberculosis (TB) were reported in Germany in 2012; of those, 65 cases were multidrug-resistant TB (MDR-TB) or extensively multidrug-resistant TB (XDR-TB) cases. However, there is only limited information on the economic consequences of drug resistance patterns on the treatment costs of MDR-and XDR-TB patients.

METHODS

On the basis of drug susceptibility of the single MDR-TB/XDR-TB strains the direct medical costs of suitable therapies were calculated according to the current guidelines of the World Health Organization (WHO) and those of the German Central Committee against Tuberculosis. These costs were combined with hospital and outpatients monitoring costs and followed the most recent German invoicing system and health statistics. Total drug and monitoring costs and were determined by Monte-Carlo simulation comprising all different options.

RESULTS

According to this, the mean drug costs were €51,113.22 (range €19,586.14 to €94,767.90). The weighted costs for hospitalization were €26,000.76 per patient compared to only €2,192.13 for primary outpatients; the total treatment costs of MDR-TB amounted to €64,429.23. These are joined by the costs due to loss of productivity, varying between €17,721.60 and €44,304. From a societal perspective, the total cost per MDR-TB/XDR-TB case reach an amount between €82,150 and €108,733 per case, respectively.

CONCLUSION

Cost analyses based on strain resistance patterns allow more reliable estimates of the real costs of treating MDR-TB/XDR-TB than do methods that ignore this factor. Advantageously, they demonstrate the economic impact of drug-resistant TB in low-incidence countries. Costs of productivity loss is of new importance because of the length of MDR-XDR therapy, but its true share of total costs has still to be determined.

Cost-effectiveness analysis of interventions for tuberculosis control: DALYs versus QALYs

The emergence of multi-drug-resistant tuberculosis (MDR-TB) in the European region and the high costs (nearly <euro>536 million) generated by the nearly 72,000 notified TB cases in the EU are the factors driving the need for development and implementation of new tools against TB. In this context, cost-effectiveness analyses applying quality-adjusted life-years (QALYs) or disability-adjusted life-years (DALYs) as outcome measures for economic evaluation of improved approaches to TB control are increasingly important. While the methodology applied to derive the effectiveness data is commonly reported, less information is given regarding the derivation of utility weights in the calculation of QALYs for TB treatment. To date, despite the particular complexities of the disease, TB health effects have not been fully measured and there is no agreement on how disutility of TB disease should be accounted for. Consequently, disutility values in published studies vary considerably, and often appear to lack empirical evidence. As the need for a solid heath-economics rationale for investment in new tools against TB grows, adequate and comprehensive methods for assessing the impairments caused by different types of TB must be developed. Focusing on the assessment of DALYs as a measure of outcome in economic evaluation, we have built an exemplary model calculation applying the original TB data for Germany as reported to the Robert Koch Institute. Our work demonstrates that the use of standard equations provided in the scientific literature probably results in an underestimation of lost DALYs compared with probabilistic techniques. Providing distributions around epidemiological averages, coupled with Monte Carlo simulation to address uncertainty, may result in more realistic values. In line with a previous recommendation by the World Health Organization, it appears worthwhile to consider this more intricate approach to providing healthcare resource allocation decisions, particularly for TB.

Drug-resistant tuberculosis

PURPOSE OF REVIEW

This review discusses the recent evidence on epidemiology, diagnosis, and treatment of drug-resistant and multidrug-resistant (MDR) tuberculosis (TB), an area where solutions for better diagnosis and treatment continually develop.

RECENT FINDINGS

The prevalence of drug resistance has been constantly rising during the recent years. It has peaked in eastern European countries such as Belarus, where a record of 35.5% MDR-TB amongst new cases have been reported from Minsk. New diagnostic tools are becoming available. Xpert MTB/RIF is by far the most promising of these new techniques. Clinical management of drug-resistant TB is still cumbersome. However, after over 40 years of neglect, new drugs are becoming readily available: delamanid, bedaquiline, and PA-824 combined into innovative regimens raise hopes for substantially higher success rates.

SUMMARY

The innovative diagnostic tools recently validated are changing the traditional paradigms of TB diagnosis, for too long based on sputum smear, culture, and drug susceptibility testing. New anti-TB compounds, which can be combined with several 'old' drugs with new indications, are gradually modifying the chances of cure for MDR-TB cases. Although initial evidence appears promising, the market use of new drugs must be accompanied by a serious public health approach aimed at preventing the development of further drug resistance.

The history and evolution of immigration medical screening for tuberculosis

Identifying and managing TB in immigrating populations has been an important aspect of immigration health for over a century, with the primary aim being protecting the host population by preventing the import of communicable diseases carried by the arriving migrants. This review describes the history and development of screening for TB and latent TB infection in the immigration context (describing both screening strategies and diagnostic tests used over the last century), outlining current practices and considering the future impact of new advances in screening. The recent focus of the WHO, regarding their elimination strategy, is further increasing the importance of diagnosing and treating latent TB infection. The last section of this review discusses the latest public health developments in the context of TB screening in immigrant populations.

Delamanid improves outcomes and reduces mortality in multidrug-resistant tuberculosis

Multidrug-resistant and extensively drug-resistant tuberculosis (TB) are associated with worse treatment outcomes for patients, including higher mortality, than for drug-sensitive tuberculosis. Delamanid (OPC-67683) is a novel anti-TB medication with demonstrated activity against multidrug-resistant disease. Patients who participated in the previously reported randomised, placebo-controlled trial of delamanid and the subsequent open-label extension trial were eligible to participate in a 24-month observational study designed to capture treatment outcomes. Treatment outcomes, as assessed by clinicians and defined by the World Health Organization, were categorised as favourable and unfavourable. Delamanid treatment groups were combined for analysis, based on their duration of treatment. In total, for 421 (87.5%) out of 481 patients from the original randomised controlled trial, consent was granted for follow-up assessments. Favourable outcomes were observed in 143 (74.5%) out of 192 patients who received delamanid for ≥6 months, compared to 126 (55%) out of 229 patients who received delamanid for ≤2 months. Mortality was reduced to 1.0% among those receiving long-term delamanid versus short-term/no delamanid (8.3%; p<0.001). Treatment benefit was also seen among patients with extensively drug-resistant TB. This analysis suggests that treatment with delamanid for 6 months in combination with an optimised background regimen can improve outcomes and reduce mortality among patients with both multidrug-resistant and extensively drug-resistant TB.

New drugs to treat tuberculosis

Tuberculosis (TB) has been a leading cause of death for more than a century. While effective therapies exist, treatment is long and cumbersome. Tuberculosis control is complicated by the overlapping problems created by global inadequacy of public health infrastructures, the interaction of the TB and human immunodeficiency virus epidemics, and the emergence of drug-resistant TB. After a long period of neglect, there is now significant progress in development of TB diagnostics and therapeutics. Focusing on treatment for active TB, we review the new pathways to TB regimen development, and the new and repurposed anti-TB agents in clinical development.