Tuberculosis and aging: a global health problem

Clinical, Radiological Features and Treatment Outcomes of Tuberculosis in Patients Aged 75 Years and Older

INTRODUCTION

Tuberculosis (TB) is a significant contributor to morbidity and mortality. With a progressively aging population, TB is increasingly encountered in older adults. Understanding the clinical presentation and optimal treatment strategies for TB in this population is essential.

METHOD

Clinical, radiological features, treatment, and outcome of patients aged 75 and above who were diagnosed with tuberculosis at King Abdulaziz Medical City in Riyadh in the period between January 2015 to December 2021wereevaluated retrospectively.

RESULTS

Among 92 elderly tuberculosis patients, most were male (76.1%) with a mean age of 82.5 years. Pulmonary TB was diagnosed in 52.2% of patients, Extra Pulmonary TB in 32.6%, and Disseminated TB in 15.2%. Comorbidities included Diabetes Mellitus (59.8%) and Congestive Heart Failure (41.3%). The most common presentation symptoms included cough (51.1%), fever (43.5%), dyspnea (39.1%), and weight loss (31.5%). Delay of TB diagnosis for up to 3 months was observed in 31.5% of patients. Weight loss and male gender were significant predictors of delayed diagnosis. Laboratory findings varied among TB types, with disseminated TB showing higher eosinophilia and thrombocytopenia. Completion of an initial RIPE treatment protocol was achieved in 67.6% of patients. Mortality during treatment occurred in 23.9% of patients. Pulmonary TB was associated with higher mortality compared to extrapulmonary TB (p = 0.007).

CONCLUSION

Tuberculosis is associated with high mortality in patients above the age of 75. There is still a substantial delay in TB diagnosis in the elderly. RIPE regimen is frequently changed due to side effects. Alternative regimen choices were quite variable. More studies on tuberculosis in this patient's population are needed to define the most effective therapeutic approach.

The Impact of Immune System Aging on Infectious Diseases

Immune system aging is becoming a field of increasing public health interest because of prolonged life expectancy, which is not paralleled by an increase in health expectancy. As age progresses, innate and adaptive immune systems undergo changes, which are defined, respectively, as inflammaging and immune senescence. A wealth of available data demonstrates that these two conditions are closely linked, leading to a greater vulnerability of elderly subjects to viral, bacterial, and opportunistic infections as well as lower post-vaccination protection. To face this novel scenario, an in-depth assessment of the immune players involved in this changing epidemiology is demanded regarding the individual and concerted involvement of immune cells and mediators within endogenous and exogenous factors and co-morbidities. This review provides an overall updated description of the changes affecting the aging immune system, which may be of help in understanding the underlying mechanisms associated with the main age-associated infectious diseases.

Comparison of the yield of two tuberculosis screening approaches among household contacts in a community setting of Silti Zone, Central Ethiopia: a prospective cohort study

BACKGROUND

Household contacts of tuberculosis (TB) patients are at a greater risk of infection and developing TB as well. Despite recommendations to actively screen such high-risk groups for TB, it is poorly implemented in Ethiopia. A community-based household contact screening was conducted to compare the yield of two different screening approaches and to identify factors associated with TB occurrence.

METHODS

Smear-positive pulmonary TB index cases from six health facilities in six districts of Silti Zone were identified and enrolled prospectively between September 2020 and December 2022. Trained healthcare workers conducted house visits to screen household contacts for TB. WHO (World Health Organization) recommended symptom-based screening algorithms were used. The yield of screening was compared between a two-time screening at study site I and a single baseline screening at study site II, which is the current programmatic approach. Generalized estimating equation was used to run multivariate logistic regression to identify factors associated with TB occurrence.

RESULTS

A total of 387 index TB cases (193 at site I and 194 at site II) with 1,276 eligible contacts were included for analysis. The TB yield of repeat screening approach did not show a significant difference compared to a single screening (2.3% at site I vs. 1.1% at site II, p < 0.072). The number needed to screen was 44 and 87 for the repeat and single screening, respectively, indicating a high TB burden in both settings. The screening algorithm for patients with comorbidities of asthma and heart failure had a 100% sensitivity, 19.1% specificity and a positive predictive value of 5.6%. Cough [AOR: 10.9, 95%CI: 2.55,46.37], fatigue [AOR: 6.1, 95%CI: 1.76,21.29], daily duration of contact with index case [AOR: 4.6, 95%CI; 1.57,13.43] and age of index cases [AOR: 0.9, 95%CI; 0.91-0.99] were associated with the occurrence of TB among household contacts.

CONCLUSION

Our study showed that the yield of TB was not significantly different between one-time screening and repeat screening. Although repeat screening has made an addition to case notification, it should be practiced only if resources permit. Cough, fatigue, duration of contact and age of index cases were factors associated with TB. Further studies are needed to establish the association between older age and the risk of transmitting TB.

Prevalence and Spatial Autocorrelation of Tuberculosis in Indigenous People in Brazil, 2002-2022

Tuberculosis (TB) among indigenous populations in Brazil poses a multifaceted public health challenge influenced by geographical, social, institutional, economic, and cultural factors. This study scrutinized the prevalence and spatial distribution of TB among Brazilian indigenous communities from 2002 to 2022. Employing a cross-sectional and descriptive approach, we analyzed data from the Notifiable Diseases Information System (SINAN) and conducted spatial autocorrelation tests to identify clusters and outliers. The findings uncovered substantial disparities in TB prevalence between the North and Central-West regions, in contrast to the South and Southeast, mirroring social, economic, and cultural inequalities in Brazil. It is concluded that public health strategies should not only consider the epidemiological aspects of TB but also encompass social and environmental determinants, notably the impact of climate change. Holistic and context-sensitive approaches are imperative for addressing TB within indigenous communities, underscoring the need for adaptive and culturally sensitive interventions in the public health landscape.

Risk Factors for Unfavorable Outcomes of Tuberculosis in Korea: Implications for Patient-Centered Care in Tuberculosis Treatment

BACKGROUND

The treatment success rate for tuberculosis (TB) has stagnated at 80-81% in South Korea, indicating unsatisfactory outcomes. Enhancing treatment success rate necessitates the development of individualized treatment approaches for each patient. This study aimed to identify the risk factors associated with unfavorable treatment outcomes to facilitate tailored TB care.

METHODS

We retrospectively analyzed the data of patients with active TB between January 2019 and December 2020 at a single tertiary referral center. We classified unfavorable treatment outcomes according to the 2021 World Health Organization guidelines as follows: "lost to follow-up" (LTFU), "not evaluated" (NE), "death," and "treatment failure" (TF). Moreover, we analyzed risk factors for each unfavorable outcome using Cox proportional hazard regression analysis.

RESULTS

A total of 659 patients (median age 62 years; male 54.3%) were included in the study. The total unfavorable outcomes were 28.1%: 4.6% LTFU, 9.6% NE, 9.1% deaths, and 4.9% TF. Multivariate analysis showed that a culture-confirmed diagnosis of TB was associated with a lower risk of LTFU (adjusted hazard ratio [aHR], 0.25; 95% confidence interval [CI], 0.10-0.63), whereas the occurrence of adverse drug reactions (ADRs) significantly increased the risk of LTFU (aHR, 6.63; 95% CI, 2.63-16.69). Patients living far from the hospital (aHR, 4.47; 95% CI, 2.50-7.97) and those with chronic kidney disease (aHR, 3.21; 95% CI, 1.33-7.75) were at higher risk of being transferred out to other health institutions (NE). Higher mortality was associated with older age (aHR, 1.06; 95% CI, 1.04-1.09) and comorbidities. The ADRs that occurred during TB treatment were a risk factor for TF (aHR, 6.88; 95% CI, 2.24-21.13).

CONCLUSION

Unfavorable outcomes of patients with TB were substantial at a tertiary referral center, and the risk factors for each unfavorable outcome varied. To improve treatment outcomes, close monitoring and the provision of tailored care for patients with TB are necessary.

Outdoor environmental exposome and the burden of tuberculosis: Findings from nearly two million adults in northwestern China

We simultaneously assessed the associations for a range of outdoor environmental exposures with prevalent tuberculosis (TB) cases in a population-based health program with 1940,622 participants ≥ 15 years of age. TB status was confirmed through bacteriological and clinical assessment. We measured 14 outdoor environmental exposures at residential addresses. An exposome-wide association study (ExWAS) approach was used to estimate cross-sectional associations between environmental exposures and prevalent TB, an adaptive elastic net model (AENET) was implemented to select important exposure(s), and the Extreme Gradient Boosting algorithm was subsequently applied to assess their relative importance. In ExWAS analysis, 12 exposures were significantly associated with prevalent TB. Eight of the exposures were selected as predictors by the AENET model: particulate matter ≤ 2.5 µm (odds ratio [OR]=1.01, p = 0.3295), nitrogen dioxide (OR=1.09, p < 0.0001), carbon monoxide (OR=1.19, p < 0.0001), and wind speed (OR=1.08, p < 0.0001) were positively associated with the odds of prevalent TB while sulfur dioxide (OR=0.95, p = 0.0017), altitude (OR=0.97, p < 0.0001), artificial light at night (OR=0.98, p = 0.0001), and proportion of forests, shrublands, and grasslands (OR=0.95, p < 0.0001) were negatively associated with the odds of prevalent TB. Air pollutants had higher relative importance than meteorological and geographical factors, and the outdoor environment collectively explained 11% of TB prevalence.

New tuberculosis vaccines in India: modelling the potential health and economic impacts of adolescent/adult vaccination with M72/AS01E and BCG-revaccination

BACKGROUND

India had an estimated 2.9 million tuberculosis cases and 506 thousand deaths in 2021. Novel vaccines effective in adolescents and adults could reduce this burden. M72/AS01E and BCG-revaccination have recently completed phase IIb trials and estimates of their population-level impact are needed. We estimated the potential health and economic impact of M72/AS01E and BCG-revaccination in India and investigated the impact of variation in vaccine characteristics and delivery strategies.

METHODS

We developed an age-stratified compartmental tuberculosis transmission model for India calibrated to country-specific epidemiology. We projected baseline epidemiology to 2050 assuming no-new-vaccine introduction, and M72/AS01E and BCG-revaccination scenarios over 2025-2050 exploring uncertainty in product characteristics (vaccine efficacy, mechanism of effect, infection status required for vaccine efficacy, duration of protection) and implementation (achieved vaccine coverage and ages targeted). We estimated reductions in tuberculosis cases and deaths by each scenario compared to the no-new-vaccine baseline, as well as costs and cost-effectiveness from health-system and societal perspectives.

RESULTS

M72/AS01E scenarios were predicted to avert 40% more tuberculosis cases and deaths by 2050 compared to BCG-revaccination scenarios. Cost-effectiveness ratios for M72/AS01E vaccines were around seven times higher than BCG-revaccination, but nearly all scenarios were cost-effective. The estimated average incremental cost was US$190 million for M72/AS01E and US$23 million for BCG-revaccination per year. Sources of uncertainty included whether M72/AS01E was efficacious in uninfected individuals at vaccination, and if BCG-revaccination could prevent disease.

CONCLUSIONS

M72/AS01E and BCG-revaccination could be impactful and cost-effective in India. However, there is great uncertainty in impact, especially given the unknowns surrounding the mechanism of effect and infection status required for vaccine efficacy. Greater investment in vaccine development and delivery is needed to resolve these unknowns in vaccine product characteristics.

Tuberculosis in older adults: challenges and best practices in the Western Pacific Region

The Western Pacific has one of the fastest-growing older adult populations globally, and tuberculosis (TB) remains one of the foremost infectious causes of disease and death in the region. Older adults are at higher risk of TB due to immunosenescence, comorbidities, and increased institutionalisation. Atypical symptoms and reduced access to health services may delay care-seeking and TB diagnosis, while co-morbidity and increased risk of adverse drug reactions complicate TB treatment. Post-TB sequelae and socioeconomic challenges may decrease the quality of life after TB treatment completion. Despite their high disease burden and special challenges, there is a lack of regionally coordinated policies and guidelines to manage TB among older adults. Routine TB screening at aged-care facilities, age-friendly infrastructure and services, awareness of atypical TB features, integration of TB and non-communicable diseases services, and person-centred approaches to treatment support could improve TB management among older adults. Addressing these challenges and adopting the best practices identified should inform policy formulation and implementation.

Funding

This project was funded by 1) the World Health Organization Regional Office for the Western Pacific, with financial contributions from the Government of the Republic of Korea through the Korean Disease Control and Prevention Agency and the Government of Japan through the Ministry of Health, Labour and Welfare, and 2) NUS Start-up Grant. The funders had no role in the paper design, collection, analysis, and interpretation of data and in writing of the paper.

Determining the Need for Additional Testing With Quantiferon TB Gold in Patients With Positive Tuberculin Skin Tests and a History of BCG Vaccination

OBJECTIVE

 To determine if the QuantiFERON-TB Gold (QFT) testing can be obviated for the diagnosis of latent tuberculosis infection (LTBI) in patients with a positive tuberculin skin test (TST) and a history of Bacillus Calmette-Guerin (BCG) vaccination by identifying high-risk features in patients with positive TST and a history of BCG vaccination who are associated with positive QFT.

METHODS

 Retrospective chart review was done for 76 adult patients by dividing them into two groups. Group 1 consisted of true positive TST patients who had BCG vaccination and were positive for QFT. Group 2 consisted of false positive TST patients who had BCG vaccination but were negative for QFT. The two groups were compared to determine if the high-risk features of TST induration diameter of 15mm and more, TST induration of 20mm and more, recent immigration to the US, the advanced age of more than 65 years, country of origin with high TB burden, known exposure to active TB, and smoking history were more prevalent in Group 1 compared to Group 2.

RESULTS

 Group 1 had 23 patients and Group 2 had 53 patients. Group 1 had a higher prevalence of patients with PPD induration of more than 10mm than Group 2, which was statistically significant with a P value of 0.03. Other risk factors of advanced age, exposure to active TB and smoking did not show statistically significant differences between Groups 1 and 2.  Conclusion: This study also confirms that if the TST induration is more than 10mm in patients with a history of BCG vaccination, the TST induration is likely because of LTBI and is less likely because of cross-reaction with BCG vaccination.

Tuberculosis in older adults: case studies from four countries with rapidly ageing populations in the western pacific region

BACKGROUND

The Western Pacific Region has one of the fastest-growing populations of older adults (≥ 65 years) globally, among whom tuberculosis (TB) poses a particular concern. This study reports country case studies from China, Japan, the Republic of Korea, and Singapore reflecting on their experiences in managing TB among older adults.

FINDINGS

Across all four countries, TB case notification and incidence rates were highest among older adults, but clinical and public health guidance focused on this population was limited. Individual country reports illustrated a range of practices and challenges. Passive case finding remains the norm, with limited active case finding (ACF) programs implemented in China, Japan, and the Republic of Korea. Different approaches have been trialled to assist older adults in securing an early diagnosis, as well as adhering to their TB treatment. All countries emphasised the need for person-centred approaches that include the creative application of new technology and tailored incentive programs, as well as reconceptualisation of how we provide treatment support. The use of traditional medicines was found to be culturally entrenched among older adults, with a need for careful consideration of their complementary use. TB infection testing and the provision of TB preventive treatment (TPT) were underutilised with highly variable practice.

CONCLUSION

Older adults require specific consideration in TB response policies, given the burgeoning aging population and their high TB risk. Policymakers, TB programs and funders must invest in and develop locally contextualised practice guidelines to inform evidence-based TB prevention and care practices for older adults.

Differential Requirement for IRGM Proteins during Tuberculosis Infection in Mice

Mycobacterium tuberculosis (Mtb) is a bacterium that exclusively resides in human hosts and remains a dominant cause of morbidity and mortality among infectious diseases worldwide. Host protection against Mtb infection is dependent on the function of immunity-related GTPase clade M (IRGM) proteins. Polymorphisms in human IRGM associate with altered susceptibility to mycobacterial disease, and human IRGM promotes the delivery of Mtb into degradative autolysosomes. Among the three murine IRGM orthologs, Irgm1 has been singled out as essential for host protection during Mtb infections in cultured macrophages and in vivo. However, whether the paralogous murine Irgm genes, Irgm2 and Irgm3, play roles in host defense against Mtb or exhibit functional relationships with Irgm1 during Mtb infection remains undetermined. Here, we report that Irgm1-/- mice are indeed acutely susceptible to aerosol infection with Mtb, yet the additional deletion of the paralogous Irgm3 gene restores protective immunity to Mtb infections in Irgm1-deficient animals. Mice lacking all three Irgm genes (panIrgm-/-) are characterized by shifted lung cytokine profiles at 5 and 24 weeks postinfection, but control disease until the very late stages of the infection, when panIrgm-/- mice display increased mortality compared to wild-type mice. Collectively, our data demonstrate that disruptions in the balance between Irgm isoforms is more detrimental to the Mtb-infected host than total loss of Irgm-mediated host defense, a concept that also needs to be considered in the context of human Mtb susceptibility linked to IRGM polymorphisms.

Immunomodulation in age-related disorders and nanotechnology interventions

Recently, the aging population has increased exponentially around the globe bringing more challenges to improve quality of life in those populations while reducing the economic burden on healthcare systems. Aging is associated with changes in the immune system culminating in detrimental effects such as immune dysfunction, immunosenescence, and chronic inflammation. Age-related decline of immune functions is associated with various pathologies including cardiovascular, autoimmune, neurodegenerative, and infectious diseases to name a few. Conventional treatment addresses the onset of age-related diseases by early detection of risk factors, administration of vaccines as preventive care, immunomodulatory treatment, and other dietary supplements. However, these approaches often come with systemic side-effects, low bioavailability of therapeutic agents, and poor outcomes seen in the elderly. Recent innovations in nanotechnology have led to the development of novel biomaterials/nanomaterials, which explore targeted drug delivery and immunomodulatory interactions in vivo. Current nanotechnology-based immunomodulatory approaches that have the potential to be used as therapeutic interventions for some prominent age-related diseases are discussed here. Finally, we explore challenges and future aspects of nanotechnology in the treatments of age-related disorders to improve quality of life in the elderly. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Cardiovascular Disease Therapeutic Approaches and Drug Discovery > Nanomedicine for Neurological Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Tuberculosis epidemiological trend in Sousse, Tunisia during twenty years (2000-2019)

Describe the epidemiology of tuberculosis in the last two decades (2000-2019) in the East region of Tunisia (city of Sousse). This was a descriptive retrospective analysis of notified incident cases of tuberculosis from 2000 to 2019 in Sousse Governorate, Tunisia. The data collection was done via the regional registry of tuberculosis. Stata software was used to characterize the socio-demographic and clinical profile of tuberculosis, to calculate its incidence, mortality and fatality rates and to determine predictive factors of mortality. R software was used to analyze the chronological trend of tuberculosis incidence and mortality. A total of 2606 incident cases of tuberculosis were declared from 2000 to 2019 in Sousse. The mean age was 39 ± 19 years with a sex ratio (male/female) of 1.19. Only one case was HIV positive among the total 2606 incident cases. Extra-pulmonary tuberculosis was the most recorded (1,534 cases, 58.9%). The mean annual case notification and deaths were 130 and four respectively. After adjusting for confounders, individuals with pulmonary tuberculosis were 1.9 significantly more likely to die from tuberculosis compared to those suffering from extra-pulmonary tuberculosis. There was a trend of increasing mortality with increasing age. The association was statistically significant only for those above 60 years' old who had 12.5 times higher odds of dying compared to those below 60 years. After adjusting for age and gender, with every year there was an increase in the total incidence rate (+0.35 per 100,000) with p = 0.005 and in the extra-pulmonary incidence (+0.27 per 100,000), with p = 0.001. This study demonstrated the increasing trend of tuberculosis in Sousse, Tunisia from 2000 to 2019. The national program against tuberculosis should enhance community knowledge and centralize the national and regional epidemiological information for better epidemiological surveillance.

Mycobacterium tuberculosis: Implications of Ageing on Infection and Maintaining Protection in the Elderly

Several reports have suggested that ageing negatively affects the human body resulting in the alteration of various parameters important for sufficient immune health. Although, the breakdown of innate and adaptive immunity has been hypothesized to increase an individual's susceptibility to infections including Mycobacteria tuberculosis (M. tb), little research has been done to bridge this gap and understand the pathophysiology underlying how ageing increases the pathogenesis of M. tb infection. Our objective was to study research from a plethora of resources to better understand the pathogenesis of ageing and its link to the human immune system. To achieve this goal, this article explores how ageing decreases the collective T-cell immune response, reduces glutathione (GSH) production, over activates the mammalian target of rapamycin (mTORC1) pathway, inhibits autophagy and mitophagy, and alters various protective genes/transcription factors. Specifically highlighting how each of these pathways cripple an individual's immune system and increases their susceptibility from M. tb infection. Furthermore, research summarized in this article gives rise to an additional mechanism of susceptibility to M. tb infection which includes a potential defect in antigen presenting by dendritic cells rather than the T-cells response. Inflammaging has also been shown to play a role in the ageing of the immune system and can also potentially be a driving factor for increased susceptibility to M. tb infection in the elderly. In addition, this article features possible preventative strategies that could decrease infections like M. tb in this population. These strategies would need to be further explored and range from immunomodulators, like Everolimus to antioxidant supplementation through GSH intake. We have also proposed the need to research these therapies in conjunction with the administration of the BCG vaccine, especially in endemic populations, to better understand the risk contracting M. tb infection as well as ways to prevent infection in the first place.

Challenges in treating tuberculosis in the elderly population in tertiary institute

Tuberculosis (TB) epidemic is most prevalent in the India with increase in mortality and morbidity. Ongoing elderly population as a result of increase in health care facilities are at high risk of TB. Elderly people are four-fold more prone to TB. Most cases of TB in the elderly result from reactivation of latent TB due to immunosenescence. Major challenge in dealing with therapeutic aspects of elderly patients is recognising frailty to prevent loss of independence. Challenges facing with elderly TB are difficult to reach out to hospital because of poor health seeking behaviour especially elderly female either due to ignorance or neglected by the family members, atypical presentation mimicking other disorders leading to diagnostic delay, if at all diagnosed impoverished tolerance and adherence to treatment due to various factors like associated comorbidities leading to pill load, impaired renal and hepatic functions with aging and stigma. Emerging resistance with usage of non-standard treatment regimens lead to unpropitious outcomes and increases mortality. The mortality rate is six times higher in elderly compared to younger individuals. Hence elderly people need tertiary level health care facilities for enhancing the diagnosis and appropriate management of tuberculosis and its complications. New set of guidelines to be made for elderly to increase adherence and tolerance thereby decreasing drug interactions and adverse drug reactions. With the increased prevalence of TB in the elderly, it is the need of the hour for India, to focus on this vulnerable population as they are a potential source of infection in the community. Awareness to be created among the elderly community regarding this deadly disease and its outcomes to increase their health consciousness and medical attention. Priming the special focus on females coterie as they are the most neglected population in our society.

Challenges in diagnosis and treatment of tuberculosis in elderly

Tuberculosis (TB) is a major infectious disease worldwide. Early diagnosis and prompt treatment reduces the transmission, morbidity and mortality in tuberculosis. Elderly (age >65 years) have many risk factors to develop tuberculosis. Recent survey in India showed incidence of TB higher in elderly. They may not have classical symptoms, clinical and radiological signs of TB which can lead to delayed diagnosis or misdiagnosis. In addition, elderly have many comorbid and coexisting diseases which make diagnosis and treatment of TB challenging. Comorbidities, poor general health status and other medications may lead to increased drug adverse reactions and poor adherence to treatment in elderly. Hence special emphasis should be given to elderly for early diagnosis and treatment. Elderly with multiple comorbidities require individualized approach for better outcome.

Tuberculosis in an Aging World

Tuberculosis (TB) is one of the leading causes of death due to its being an infectious disease, caused by the airborne pathogen Mycobacterium tuberculosis (M.tb). Approximately one-fourth of the world’s population is infected with latent M.tb, and TB is considered a global threat killing over 4000 people every day. The risk of TB susceptibility and mortality is significantly increased in individuals aged 65 and older, confirming that the elderly represent one of the largest reservoirs for M.tb infection. The elderly population faces many challenges that increase their risk of developing respiratory diseases, including TB. The challenges the elderly face in this regard include the following: decreased lung function, immuno-senescence, inflammaging, adverse drug effects, low tolerance to anti-TB drugs, lack of suitable diagnoses/interventions, and age-associated comorbidities. In order to find new therapeutic strategies to maintain lung homeostasis and resistance to respiratory infections as we age, it is necessary to understand the molecular and cellular mechanisms behind natural lung aging. This review focuses primarily on why the elderly are more susceptible to TB disease and death, with a focus on pulmonary function and comorbidities.

Psychological stress creates an immune suppressive environment in the lung that increases susceptibility of aged mice to Mycobacterium tuberculosis infection

Age is a major risk factor for chronic infections, including tuberculosis (TB). Elderly TB patients also suffer from elevated levels of psychological stress. It is not clear how psychological stress impacts immune response to Mycobacterium tuberculosis (M.tb). In this study, we used social disruption stress (SDR) to investigate effects of psychological stress in young and old mice. Unexpectedly, we found that SDR suppresses lung inflammation in old mice as evidenced by lower pro-inflammatory cytokine levels in bronchial lavage fluid and decreased cytokine mRNA expression by alveolar macrophages. To investigate effects of stress on M.tb infection, mice were subjected to SDR and then infected with M.tb. As previously reported, old mice were better at controlling infection at 30 days than young mice. This control was transient as CFUs at 60 days were higher in old control mice compared to young mice. Consistently, SDR significantly increased M.tb growth at 60 days in old mice compared to young mice. In addition, SDR in old mice resulted in accumulation of IL-10 mRNA and decreased IFN-γ mRNA at 60 days. Also, confocal microscopy of lung sections from old SDR mice showed increased number of CD4 T cells which express LAG3 and CD49b, markers of IL-10 secreting regulatory T cells. Further, we also demonstrated that CD4 T cells from old SDR mice express IL-10. Thus, we conclude that psychological stress in old mice prior to infection, increases differentiation of IL-10 secreting T cells, which over time results in loss of control of the infection.

Determinants of unsuccessful tuberculosis treatment outcome in Northern Red Sea region, Eritrea

Background

Eritrea has achieved the global target (90%) for tuberculosis (TB) treatment success rate. Though, events of unsuccessful TB treatment outcomes (death, treatment failure, lost to follow up and not evaluated) could lead to further TB transmission and the development of resistant strains. Hence, factors related to these events should be explored and addressed. This study aims to fill the gap in evidence by identifying the determinants of unsuccessful TB treatment outcomes in Eritrea’s Northern Red Sea region.

Methods

A retrospective cohort study was conducted in Eritrea’s Northern Red Sea region. Data collected using a data extraction tool was analyzed using Stata version 13. Frequencies, proportions, median and standard deviations were used to describe the data. Furthermore, univariable and multivariable logistic regression analysis were performed to determine the risk factors for unsuccessful TB treatment outcomes. Crude odds ratio (COR) and adjusted odds ratio (AOR) with their 95% confidence interval (CI) presented and p-value < 0.05 was considered statistically significant.

Results

Among 1227 TB patients included in this study, 9.6% had unsuccessful TB treatment outcomes. In multivariable logistic regression analysis, TB cases 55–64 years old (AOR: 2.75[CI: 1.21–6.32], p = 0.016) and those ≥ 65 years old (AOR: 4.02[CI: 1.72–9.45], p = 0.001) had 2.7 and 4 times higher likelihood of unsuccessful TB treatment outcome respectively. In addition, HIV positive TB patients (AOR: 5.13[CI: 1.87–14.06], p = 0.002) were 5 times more likely to have unsuccessful TB treatment outcome. TB treatment in Ghindae Regional Referral Hospital (AOR: 5.01[2.61–9.61], p < 0.001), Massawa Hospital (AOR: 4.35[2.28–8.30], p< 0.001) and Nakfa Hospital (AOR: 2.53[1.15–5.53], p = 0.021) was associated with 5, 4 and 2.5 higher odds of unsuccessful TB treatment outcome respectively.

Conclusion

In this setting, old age, HIV co-infection and health facility were the independent predictors of unsuccessful TB treatment outcome.

Epidemiological features of tuberculosis infection in a rural prefecture of Japan from 2007 to 2018

This study aimed to investigate the epidemiological features of reported tuberculosis (TB) infections in a western prefecture (Nagasaki Prefecture) from 2007 to 2018, and to identify the high-risk group for TB infection. The characteristics of 12 years of reported TB infections from the Nagasaki Prefectural Informational Center of Infectious Diseases were summarized by median (interquartile range [IQR]) and proportion; the annual TB infections’ notification rate regarding sex/age was calculated accordingly. The diagnosis of TB infection was made according to clinic symptoms and laboratory examination. In total, 4364 TB infections were reported in 2007 and 2018, with a median age (IQR) of 74 (55–84) years. The majority of TB infections were male (52.6%, 2297/4364), > 65 years (65.8%, 2869/4364), and indigenous (98.1%, 4276/4364). Among active TB, 66.9% (1833/2740) had pulmonary TB, and 25.3% (694/2740) were diagnosed as extrapulmonary TB. The highest notification rate of TB infection was observed in the elderly male population (> 85 years). The annual notification rate of TB infections ranged between 19.4/and 34.0/100,000 for 12 years. The notification rates of TB infections were high in older people of both sexes, especially in men aged > 85. Therefore, appropriate interventions and health management are essential for TB control in (and with a focus on) the elderly population.

Incidence and outcomes of adverse drug reactions to first-line anti-tuberculosis drugs and their effects on the quality of life: a multicenter prospective cohort study

BACKGROUND

In tuberculosis (TB) treatment, adverse drug reactions (ADRs) can interrupt treatment and decrease the quality of life (QoL). We aimed to prospectively investigate the incidence of ADRs to first-line anti-TB drugs and related outcomes and QoL.

METHODS

Adult patients with TB who had been treated with first-line anti-TB drugs in five Korean hospitals were enrolled. ADR questionnaire surveys and blood tests were performed four times serially, and QoL was assessed on the fourth TB treatment week (± two weeks).

RESULTS

Of 410 enrolled patients with TB (males, 62%; mean age, 52.1 ± 18.1 years [those aged ≥65 years, 26.6%]), 67.8% experienced any ADRs (≥ grade 2) to TB drugs. The most common ADR was fatigue (53.2%), followed by itching (42.7%) and anorexia (41.7%). Older adult patients experienced relatively more ADRs, including anorexia, dyspepsia, rash, dizziness, anemia, abnormal hepatic/renal function tests, and increased uric acid levels (P < 0.05). Treatment regimens changed for 9.5% of patients owing to ADRs to anti-TB drugs. Patients with any ADRs and older adult patients had significantly lower QoL than their counterparts (P < 0.05). Old age (odds ratio [OR], 1.02) and being male (OR 2.65) were independently associated with ADRs, whereas active smoking (OR 4.73) and a relatively long treatment phase (OR 5.13) were independently associated with hepatotoxicity.

CONCLUSION

ADRs to first-line anti-TB drugs were common and related to relatively low QoL, especially among older adults. Although 9.5% of patients had ADR-related regimen changes, most patients with ADRs completed treatments successfully. This article is protected by copyright. All rights reserved.

Risk factors associated with tuberculosis recurrence in South Korea determined using a nationwide cohort study

Objective

Prevention of tuberculosis (TB) recurrence is an important issue in TB control. South Korea, a country with a high average income, has been challenged with an intermediate burden of TB. We aimed to estimate the TB recurrence rate after successful completion of the first anti-TB chemotherapy, and to identify the risk factors for the TB recurrence by focusing on co-morbidities and behavioral factors.

Methods

This is a population-based cohort study using data from the National Health Insurance (NHI) database between 2002 and 2013. Newly diagnosed TB patients were identified using the classification of disease codes and prescription records. Final analytical subjects included people who successfully completed the first anti-TB chemotherapy. The primary outcome measure was recurrent TB 6-month after the first treatment completion. A set of associated risk factors, including demographic characteristics, co-morbidities, and health behavior factors were analyzed using Cox regression analysis.

Results

Among 5,446 TB patients, 2,226 (40.1%) completed the first anti-TB treatment. During the follow-up period, 150 (6.7%) patients had TB recurrence, and the crude recurrent rate was 22.6 per 1000 person-years. The majority of recurrence cases (89%) occurred within the first 2-year period. The major findings show that participants who are male (adjusted HR (aHR) = 1.81, at a 95% CI, range: 1.11–2.94), older in age (aHR = 1.07, at a 95% CI, range: 1.00–1.14), have a lower income (aHR = 1.96, at a 95% CI, range: 1.10–3.48) and who are underweight (aHR = 1.92, at a 95% CI, range 1.15–3.20) were at higher risks for TB recurrence.

Conclusion

People who have risk factors for recurrent TB need to improve treatment compliance through more effective TB management, and follow-up observation for one or two years after the treatment completion.

Cluster analysis categorizes five phenotypes of pulmonary tuberculosis

Tuberculosis (TB) has a heterogeneous phenotype, which makes it challenging to diagnose. Our study aimed to identify TB phenotypes through cluster analysis and compare their initial symptomatic, microbiological and radiographic characteristics. We systemically collected data of notified TB patients notified in Korea and constructed a prospective, observational cohort database. Cluster analysis was performed using K-means clustering, and the variables to be included were determined by correlation network. A total of 4,370 subjects with pulmonary TB were enrolled in the study. Based on the correlation network, age and body mass index (BMI) were selected for the cluster analysis. Five clusters were identified and characterised as follows: (1) middle-aged overweight male dominance, (2) young-aged relatively female dominance without comorbidities, (3) middle-aged underweight male dominance, (4) overweight elderly with comorbidities and (5) underweight elderly with comorbidities. All clusters had distinct demographic and symptomatic characteristics. Initial microbiologic burdens and radiographic features also varied, including the presence of cavities and bilateral infiltration, which reflect TB-related severity. Cluster analysis of age and BMI identified five phenotypes of pulmonary TB with significant differences at initial clinical presentations. Further studies are necessary to validate our results and to assess their clinical implications.

Multidrug-Resistant Tuberculosis Treatment Outcome and Associated Factors at the University of Gondar Comprehensive Specialized Hospital: A Ten-Year Retrospective Study

Background

Multidrug-resistant tuberculosis (MDR-TB) remains a public health crisis and a health security threat worldwide. Poor public health infrastructure, inefficient infection control and mismanagement of TB treatment are among the reasons for the continuous emergence and spread of drug-resistant TB (DR-TB). The final treatment outcome is the most direct measurement of TB control programs. Therefore, this study sought to determine the proportions and predictors of TB treatment outcomes among MDR/RR-TB treated patients.

Methods

A 10-year, 2011 to 2021, hospital-based retrospective cohort study was conducted at the University of Gondar Comprehensive Specialized Hospital. The records of 408 MDR-TB patients, 389 with treatment outcome and 19 on treatment, were collected using a structured checklist.

Results

A total of 389 patients with a recorded MDR/RR-TB treatment outcome were included. The treatment success rate was 77.12%, with 58.35% cured and 18.76% treatment completed. The proportion of death rate, treatment default loss to follow-up, treatment failure, and unknown treatment outcome was 9.25%, 6.94%, 3.1%, and 3.6%, respectively. Regarding the patient category, the most successful treatment outcome (83.5%) came from patients diagnosed with relapse cases, followed by new cases (81.8%). An unsuccessful treatment outcome was significantly associated with patients aged >44 years (AOR, 3.3, 95% CI = 1.55–6.99).

Conclusion and Recommendations

This study indicated that nearly 23% of MDR/RR-TB patients had unsuccessful treatment outcomes and being older was significantly correlated with these outcomes. For better outcomes, it is recommended to strengthen combined treatment adherence interventions and evaluate treatment regimens and administration options. A prospective cohort study may be required to investigate the full range of potential causes of unfavorable outcomes.

Multidrug-resistant and extensively drug-resistant Mycobacterium tuberculosis strains in geriatrics: An analysis and its implications in tuberculosis control

Objective

This study aimed to analyze the trends of tuberculosis (TB) disease, drugs susceptibility patterns in geriatric TB over a period of three years (from 2010 to 2012).

Materials & methods

In this study, laboratory data on diagnosis of geriatric tuberculosis suspected patients (age ≥60 years) was analyzed retrospectively at National Reference Laboratory (NRL).

Results

Among 12,140 geriatric TB suspects, 1621 (13%) were acid-fast bacillus (AFB) smear-positive and 10,519 (87%) were smear-negative. Analysis of 915 culture results showed 470 (51%) as positive for Mycobacterium tuberculosis complex (MTBC), 63 (7%) contaminated and 36 (4%) identified as mycobacteria other than tuberculosis (MOTT). A total 210/470 (45%) were multidrug-resistant TB (MDR-TB) strains. Among the mono-resistant strains, isoniazid mono-resistant was found more frequently (134/470, 28%) whereas, it was least among rifampicin mono-resistant 5/470 (1%). The second-line drug susceptibility testing (DST) results showed 7% (17/240) extensively drug-resistant TB (XDR-TB) strains. Most common second line mono-resistant strain was observed with ofloxacin, 16% (38/240).

Conclusion

This study shows high number of MDR/XDR geriatric TB patients at tertiary care TB hospital. The study highlighted the need of separate line of early identification, diagnosis and treatment of geriatric TB patients. However, further study with improved sample size may needed to confirm the findings.

Host Metabolic Changes during Mycobacterium Tuberculosis Infection Cause Insulin Resistance in Adult Mice

Tuberculosis (TB) is a highly infectious bacterial disease that primarily attacks the lungs. TB is manifested either as latent TB infection (LTBI) or active TB disease, the latter posing a greater threat to life. The risk of developing active TB disease from LTBI is three times higher in individuals with type 2 diabetes mellitus (T2DM). The association between TB and T2DM is becoming more prominent as T2DM is rapidly increasing in settings where TB is endemic. T2DM is a chronic metabolic disorder characterized by elevated blood glucose, insulin resistance, and relative insulin deficiency. Insulin resistance and stress-induced hyperglycemia have been shown to be increased by TB and to return to normal upon treatment. Previously, we demonstrated that adipocytes (or fat tissue) regulate pulmonary pathology, inflammation, and Mycobacterium tuberculosis (Mtb) load in a murine model of TB. Metabolic disturbances of adipose tissue and/or adipocyte dysfunction contribute to the pathogenesis of T2DM. Thus, pathological adipocytes not only regulate pulmonary pathology, but also increase the risk for T2DM during TB infection. However, the cellular and molecular mechanisms driving the interaction between hyperglycemia, T2DM and TB remain poorly understood. Here, we report the impact of Mtb infection on the development of insulin resistance in mice fed on a regular diet (RD) versus high-fat diet (HFD) and, conversely, the effect of hyperglycemia on pulmonary pathogenesis in juvenile and adult mouse models. Overall, our study demonstrated that Mtb persists in adipose tissue and that Mtb infection induces irregular adipocyte lipolysis and loss of fat cells via different pathways in RD- and HFD-fed mice. In RD-fed mice, the levels of TNFα and HSL (hormone sensitive lipase) play an important role whereas in HFD-fed mice, ATGL (adipose triglyceride lipase) plays a major role in regulating adipocyte lipolysis and apoptosis during Mtb infection in adult mice. We also showed that Mtb infected adult mice that were fed an RD developed insulin resistance similar to infected adult mice that were overweight due to a HFD diet. Importantly, we found that a consequence of Mtb infection was increased lipid accumulation in the lungs, which altered cellular energy metabolism by inhibiting major energy signaling pathways such as insulin, AMPK and mToR. Thus, an altered balance between lipid metabolism and glucose metabolism in adipose tissue and other organs including the lungs may be an important component of the link between Mtb infection and subsequent metabolic syndrome.

Examining pulmonary TB patient management and healthcare workers exposures in two public tertiary care hospitals, Bangladesh

Implementation of tuberculosis (TB) infection prevention and control (IPC) guidelines in public tertiary care general hospitals remain challenging due to limited evidence of pulmonary TB (PTB) patients' duration of hospital stay and management. To fill this evidence gap, this study examined adult PTB patient management, healthcare workers' (HCWs) exposures and IPC practices in two public tertiary care hospitals in Bangladesh.Between December 2017 and September 2019, a multidisciplinary team conducted structured observations, a hospital record review, and in-depth interviews with hospital staff from four adult medicine wards.Over 20 months, we identified 1,200 presumptive TB patients through the hospital record review, of whom 263 were confirmed PTB patients who stayed in the hospital, a median of 4.7 days without TB treatment and possibly contaminated the inpatients wards. Over 141 observation hours, we found a median of 3.35 occupants present per 10 m2 of floor space and recorded a total of 17,085 coughs and 316 sneezes: a median of 3.9 coughs or sneezes per 10 m2 per hour per ward. Only 8.4% of coughs and 21% of sneezes were covered by cloths, paper, tissues, or by hand. The HCWs reportedly could not isolate the TB patients due to limited resources and space and could not provide them with a mask. Further, patients and HCWs did not wear any respirators.The study identified that most TB patients stayed in the hospitals untreated for some duration of time. These PTB patients frequently coughed and sneezed without any facial protection that potentially contaminated the ward environment and put everyone, including the HCWs, at risk of TB infection. Interventions that target TB patients screening on admission, isolation of presumptive TB patients, respiratory hygiene, and HCWs' use of personal protective equipment need to be enhanced and evaluated for acceptability, practicality and scale-up.

INERTIAL SENSOR-BASED MOTION ANALYSIS SYSTEM OF BRIDGE-STYLE MOVEMENT FOR REHABILITATION TREATMENTS

In the clinical course of the treatment, impartial representation of the patients’ rehabilitation state is a necessary condition for taking the best treatment to match the state of the current recovery. Bridge-style movement is one of the earliest training programs of the bed position change and is also the basis of successful standing and walking training because the bridge-style movement can inhibit the spasticity pattern of lower limb extensors and improve the control and coordination ability from the pelvis to lower limb. However, patients’ bridge-style movement planning for the current rehabilitation state largely depends on therapists’ clinical experience and subjective that may deteriorate the rehabilitation effect. Thus, it is necessary for hemiplegic patients to develop quantitative motor function assessment to judge its current rehabilitation state. This paper proposes a quantitative evaluating method to detect patients’ bridge-style movement posture and analyze their motion abilities. The real-time postural change of the bridge-style movement can be acquired by the inertial sensors attached to the waist, thigh, and crus. The bridge-style movement process of patients is recorded and analyzed by the software processing program. Finally, the experiment can be carried out to verify the feasibility and correctness of the evaluation method. The experimental results show that the evaluation method can judge patients’ current motion ability and rehabilitation state. And it is helpful for therapists to carry out targeted training for patients’ state.

Risk and characteristics of tuberculosis after anti-tumor necrosis factor therapy for inflammatory bowel disease: a hospital-based cohort study from Korea

BACKGROUND

Anti-tumor necrosis factor (TNF) treatment for inflammatory bowel disease (IBD) increases the risk of tuberculosis (TB) infection. In the present study, we analyzed the clinical characteristics and risks of TB in Korean patients with IBD who received anti-TNF treatment.

METHODS

The study included patients with IBD who were treated using anti-TNF agents between January 2001 and June 2018 at the Asan Medical Center. Overall, 1434 patients with ulcerative colitis or Crohn's disease were enrolled. We calculated the incidence of active TB infection after anti-TNF treatment and compared the clinical characteristics of the TB group with those of the non-TB group.

RESULTS

Twenty-one patients (1.46%) developed active TB infection, and the incidence rate of active TB was 366.73 per 100,000 person-years. In total, 198 patients (14.9%) were positive for latent tuberculosis infection (LTBI), of whom only eight (4%) did not complete LTBI treatment. The age at which the anti-TNF therapy was started was significantly higher in the TB group than in the non-TB group (HR 1.041, 95% CI 1.014-1.069, p = 0.002), and as age increased, so did the incidence rate of active TB infection (linearity p < 0.001). There was no significant difference in the incidence rate of LTBI between the TB and non-TB groups (HR 0.896, 95% CI 0.262-3.066, p = 0.862).

CONCLUSIONS

In patients with IBD, the incidence rate of TB increased with age at anti-TNF therapy initiation. Active treatment of LTBI may lower the incidence of TB in patients with IBD who are to undergo anti-TNF therapy.

Seasonality of tuberculosis in intermediate endemicity setting dominated by reactivation diseases in Hong Kong

Summer-spring predominance of tuberculosis (TB) has been widely reported. The relative contributions of exogenous recent infection versus endogenous reactivation to such seasonality remains poorly understood. Monthly TB notifications data between 2005 and 2017 in Hong Kong involving 64,386 cases (41% aged ≥ 65; male-to-female ratio 1.74:1) were examined for the timing, amplitude, and predictability of variation of seasonality. The observed seasonal variabilities were correlated with demographics and clinical presentations, using wavelet analysis coupled with dynamic generalised linear regression models. Overall, TB notifications peaked annually in June and July. No significant annual seasonality was demonstrated for children aged ≤ 14 irrespective of gender. The strongest seasonality was detected in the elderly (≥ 65) among males, while seasonal pattern was more prominent in the middle-aged (45–64) and adults (30–44) among females. The stronger TB seasonality among older adults in Hong Kong suggested that the pattern has been contributed largely by reactivation diseases precipitated by defective immunity whereas seasonal variation of recent infection was uncommon.

A scoping review on climate change and tuberculosis

Climate change is a global public health challenge. The changes in climatic factors affect the pattern and burden of tuberculosis, which is a worldwide public health problem affecting low and middle-income countries. However, the evidence related to the impact of climate change on tuberculosis is few and far between. This study is a scoping review following a five-stage version of Arksey and O'Malley's method. We searched the literature using the keywords and their combination in Google scholar, and PubMed. Climate change affects tuberculosis through diverse pathways: changes in climatic factors like temperature, humidity, and precipitation influence host response through alterations in vitamin D distribution, ultraviolet radiation, malnutrition, and other risk factors. The rise in extreme climatic events induces population displacement resulting in a greater number of vulnerable and risk populations of tuberculosis. It creates a conducive environment of tuberculosis transmission and development of active tuberculosis and disrupts tuberculosis diagnosis and treatment services. Therefore, it stands to reasons that climate change affects tuberculosis, particularly in highly vulnerable countries and areas. However, further studies and novel methodologies are required to address such a complex relationship and better understand the occurrence of tuberculosis attributable to climate change.

Acute Inflammation Confers Enhanced Protection against Mycobacterium tuberculosis Infection in Mice

Inflammation plays a crucial role in the control of Mycobacterium tuberculosis infection. In this study, we demonstrate that an inflammatory pulmonary environment at the time of infection mediated by lipopolysaccharide treatment in mice confers enhanced protection against M. tuberculosis for up to 6 months postinfection. This early and transient inflammatory environment was associated with a neutrophil and CD11b+ cell influx and increased inflammatory cytokines. In vitro infection demonstrated that neutrophils from lipopolysaccharide-treated mice exhibited increased association with M. tuberculosis and had a greater innate capacity for killing M. tuberculosis. Finally, partial depletion of neutrophils in lipopolysaccharide-treated mice showed an increase in M. tuberculosis burden, suggesting neutrophils played a part in the protection observed in lipopolysaccharide-treated mice. These results indicate a positive role for an inflammatory environment in the initial stages of M. tuberculosis infection and suggest that acute inflammation at the time of M. tuberculosis infection can positively alter disease outcome. IMPORTANCE Mycobacterium tuberculosis, the causative agent of tuberculosis disease, is estimated to infect one-fourth of the world's population and is one of the leading causes of death due to an infectious disease worldwide. The high-level variability in tuberculosis disease responses in the human populace may be linked to immune processes related to inflammation. In many cases, inflammation appears to exasperate tuberculosis responses; however, some evidence suggests inflammatory processes improve control of M. tuberculosis infection. Here, we show an acute inflammatory stimulus in mice provides protection against M. tuberculosis for up to 6 months, suggesting acute inflammation can positively affect M. tuberculosis infection outcome.

Estimating the burden of nosocomial exposure to tuberculosis in South Korea, a nationwide population based cross-sectional study

BACKGROUND/AIMS

The aim of the study was to investigate the current nationwide burden of nosocomial exposure to tuberculosis (TB) using national health insurance claims data.

METHODS

All patients who had claims for drug susceptibility testing for TB from 2012 to 2016, which indicated culture-proven TB, were included. The first day of the infectious period was defined as 3 months before a doctor's suspicion of TB in patients with respiratory symptoms and 1 month before in patients without symptoms. The last day of the infectious period was defined as one day before the prescription of anti-TB medications. Patients hospitalized during infectious periods were investigated and their hospitalization days were calculated. Records of medical procedures which increased the risk of nosocomial transmission by generating aerosols were also investigated.

RESULTS

A total of 7,186 cases with 94,636 person-days of hospitalization with unrecognized active TB were found. Patients above 60 years of age accounted for 63.99% of the total number and 69.70% of the total duration of hospitalization. TB patients in the older age group showed a trend toward higher risks for hospitalization with unrecognized active TB. Patients in their 80s showed the highest risk (12.65%). Bronchoscopy (28.86%), nebulizer therapy (28.48%), and endotracheal intubation (13.02%) were common procedures performed in these patients during hospitalization.

CONCLUSION

The burden of nosocomial exposure to TB in South Korea is still substantial. Hospitalization with unrecognized active TB, especially among the elderly TB patients could be a serious public health issue in South Korea.

Long-term trends of tuberculosis incidence and mortality in four central African countries

Tuberculosis (TB) incidence and mortality rates are still high in Sub-Saharan Africa, and the knowledge about the current patterns is valuable for policymaking to decrease the TB burden. Based on the Global Burden of Disease (GBD) study 2019, we used a Joinpoint regression analysis to examine the variations in the trends of TB incidence and mortality, and the age-period-cohort statistical model to evaluate their risks associated with age, period, and cohort in males and females from Cameroon (CAM), Central African Republic (CAR), Chad, and the Democratic Republic of the Congo (DRC). In the four countries, TB incidence and mortality rates displayed decreasing trends in men and women; except for the males from DRC that recorded an almost steady pattern in the trend of TB incidence between 1990 and 2019. TB incidence and mortality rates decreased according to the overall annual percentage changes over the adjusted age category in men and women of the four countries, and CAM registered the highest decrease. Although TB incidence and mortality rates increased with age between 1990 and 2019, the male gender was mainly associated with the upward behaviors of TB incidence rates, and the female gender association was with the upward behaviors of TB mortality rates. Males and females aged between 15–54 and 15–49 years old were evaluated as the population at high risks of TB incidence and mortality respectively in CAM, CAR, Chad, and DRC. The period and cohort relative risks (RRs) both declined in men and women of the four countries although there were some upward behaviors in their trends. Relatively to the period and cohort RRs, females and males from CAM recorded the most significant decrease compared to the rest of the countries. New public health approaches and policies towards young adults and adults, and a particular focus on elderlies’ health and life conditions should be adopted in CAM, CAR, DRC, and Chad to rapidly decrease TB incidence and mortality in both genders of the four countries.

A prospective cross-sectional study of tuberculosis in elderly Hispanics reveals that BCG vaccination at birth is protective whereas diabetes is not a risk factor

BACKGROUND

Aging increases the risk of tuberculosis (TB) and its adverse outcomes, but most studies are based on secondary analyses, and few are in Hispanics. Diabetes is a risk factor for TB in adults, but its contribution in the elderly is unknown. We aimed to identify the role of diabetes and other risk factors for TB in elderly Hispanics.

METHODS

Cross-sectional study among newly-diagnosed TB patients, recent contacts (ReC), or community controls (CoC) totaling 646 participants, including 183 elderly (>60 years; 43 TB, 80 ReC, 60 CoC) and 463 adults (18 to 50 years; 80 TB, 301 ReC and 82 CoC). Host characteristics associated with TB and latent Mycobacterium tuberculosis infection (LTBI) were identified in the elderly by univariable and confirmed by multivariable logistic regression.

RESULTS

LTBI was more prevalent among the elderly CoC (55% vs. 23.2% in adults; p<0.001), but not in ReC (elderly 71.3% vs. adult 63.8%); p = 0.213). Risk factors for TB in the elderly included male sex (adj-OR 4.33, 95% CI 1.76, 10.65), smoking (adj-OR 2.55, 95% CI 1.01, 6.45) and low BMI (adj-OR 12.34, 95% CI 4.44, 34.33). Unexpectedly, type 2 diabetes was not associated with TB despite its high prevalence (adj-OR 0.38, 95% CI 0.06, 2.38), and BCG vaccination at birth was protective (adj-OR 0.16, 95% CI 0.06, 0.45).

CONCLUSIONS

We report novel distinctions in TB risk factors in the elderly vs. adults, notably in diabetes and BCG vaccination at birth. Further studies are warranted to address disparities in this vulnerable, understudied population.

Immune age and biological age as determinants of vaccine responsiveness among elderly populations: the Human Immunomics Initiative research program

The Human Immunomics Initiative (HII), a joint project between the Harvard T.H. Chan School of Public Health and the Human Vaccines Project (HVP), focuses on studying immunity and the predictability of immuneresponsiveness to vaccines in aging populations. This paper describes the hypotheses and methodological approaches of this new collaborative initiative. Central to our thinking is the idea that predictors of age-related non-communicable diseases are the same as predictors for infectious diseases like COVID-19 and influenza. Fundamental to our approach is to differentiate between chronological, biological and immune age, and to use existing large-scale population cohorts. The latter provide well-typed phenotypic data on individuals’ health status over time, readouts of routine clinical biochemical biomarkers to determine biological age, and bio-banked plasma samples to deep phenotype humoral immune responses as biomarkers of immune age. The first phase of the program involves 1. the exploration of biological age, humoral biomarkers of immune age, and genetics in a large multigenerational cohort, and 2. the subsequent development of models of immunity in relation to health status in a second, prospective cohort of an aging population. In the second phase, vaccine responses and efficacy of licensed COVID-19 vaccines in the presence and absence of influenza-, pneumococcal- and pertussis vaccines routinely offered to elderly, will be studied in older aged participants of prospective population-based cohorts in different geographical locations who will be selected for representing distinct biological and immune ages. The HII research program is aimed at relating vaccine responsiveness to biological and immune age, and identifying aging-related pathways crucial to enhance vaccine effectiveness in aging populations.

Nontuberculous mycobacterial pulmonary disease and associated risk factors in China: A prospective surveillance study

BACKGROUND

We aimed to address the knowledge gap that exists regarding the epidemiological, demographic, and clinical characteristics of nontuberculous mycobacterial pulmonary diseases (NTM-PDs) among smear-positive patients with symptoms suggestive of pulmonary tuberculosis (PTB) in China.

METHODS

Prospective and national surveillance of NTM-PD was performed from 17 hospitals within the China Nontuberculous Mycobacteria Surveillance Study (CNTMS). Patients were eligible for inclusion if they had positive smears during hospitalization. Sputum specimens were collected for molecular species identification.

RESULTS

6,766 patients with valid results were included, consisting of 6,236 (92.2%) with PTB, 458 (6.8%) with NTM-PD, and 72 (1.0%) with colonization. The proportion of NTM-PD in PTB patients exhibited significant geographic diversity, ranging from 3.2% in the northwest to 9.2% in the south. The most prevalent species was Mycobacterium intracellulare, followed by Mycobacterium abscessus complex. Females, elderly people, and patients with bronchiectasis or COPD are at high risk for developing NTM-PD, while patients with diabetes have a lower risk of NTM-PD when compared with non-diabetic patients. Regarding clinical symptoms, lower rates of persistent cough and weight loss were noted in NTM-PD patients than in PTB patients.

CONCLUSIONS

Approximately one-fifteenth of PTB patients are afflicted with nontuberculous mycobacterial infections in China. The prevalence of NTM shows geographic diversity across the country, and it showed a gradual increase from north to south and from west to east. NTM-PD patients are prone to exhibit less severe clinical symptoms than PTB patients, highlighting the importance of raising awareness of NTM diseases to improve decision making on how to best screen, diagnose, and treat NTM in TB-endemic settings.

Time-dependent association between cancer and risk of tuberculosis: A population-based cohort study

BACKGROUND

We aimed to investigate the time-dependent association between cancer and the risk of tuberculosis (TB) before and after cancer diagnosis.

METHODS

This population-based cohort study incorporated the National Health Insurance Research Database and the National Health Interview Survey in Taiwan to estimate TB risk in cancer and noncancer populations. We estimated the period-specific incidence rate ratio (IRR) between cancer and risk of TB and used Cox proportional hazards models to estimate the average hazard ratio between cancer and TB during the peridiagnostic period.

RESULTS

From 2001 to 2015, 457 673 cancer and 3 738 122 noncancer individuals were enrolled. After stratifying the IRR of TB by year relative to the date of cancer diagnosis, the peak IRRs clustered in the year before and after the index date. In the peridiagnostic period of cancer, the adjusted hazard ratio was 2.29 (95% CI, 2.22-2.35) using the Cox model and 2.20 (95% CI, 2.09-2.32) after adjustment for missing confounders. Patients with cancers in the respiratory tract, upper digestive tract, and hematologic system were at the highest risk for TB.

CONCLUSIONS

Cancer is an independent risk factor for TB, with the highest risk observed around the time of cancer diagnosis.

[Unusual presentation of late reactivated tuberculosis in immunosenescence after nine decades latency]

INTRODUCTION

 Tuberculosis is an often underestimated infectious disease which can lead to manifest infections even after years of latency. Pulmonary manifestations are by far the most frequent, although any other organ can be equally affected.

HISTORY

 A 95-year old patient presented with a localized painful swelling of the right foot for further investigation. Despite her advanced age there were no pre-existing medical conditions, except for a club foot existing since early childhood.

FINDINGS AND DIAGNOSIS

 On physical examination we found a hyperemic fluctuant swelling of 5 cm diameter at the arch of the right foot. The X-ray showed a complete destruction of the regular osseous structures from the upper ankle joint to the proximal metatarsal bones.

THERAPY AND COURSE

 Intraoperatively the suspicion of an abscess was confirmed and material was obtained for microbiological investigation. Liquid cultures grew Mycobacterium tuberculosis. In an MRI-scan, involvement of the tarsal and metatarsal bones could not be excluded, thus the duration of the standard antituberculose treatment was set to 9 months.

CONCLUSIONS

 Tuberculosis, primary or reactivated, should always be considered as a potential cause of unclear infections; especially in patients with anticipated immunosenescence.

Assessment of Strategies and Epidemiological Characteristics of Tuberculosis in Henan Province, China: Observational Study

Background

In 2005, China established an internet-based Tuberculosis Information Management System (TBIMS) to monitor changes in tuberculosis (TB). Many scholars have conducted epidemiological research using TBIMS; however, few studies assessing control strategies have been performed based on this platform data. Henan province is a high TB incidence area in China where, in addition to following the nationwide TB strategies, a series of local intervention combinations have been implemented.

Objective

Our study aims to evaluate the impact of nationwide TB intervention combinations on epidemiological changes and determine whether Henan province can achieve the World Health Organization’s (WHO) goal of reducing TB incidence by 50% and TB mortality by 75% by the year 2025.

Methods

We used descriptive statistical methods to show the spatial and temporal distribution of pulmonary tuberculosis (PTB) reported to the TBIMS database from 2005 to 2018, and logistic regression analysis was performed to identify the risk factors of bacteriological-positive TB. The dynamic compartmental model and Bayesian melding approach was adopted to estimate the burden of TB under the impact of different TB control policies.

Results

In total, 976,526 PTB cases were notified to the TBIMS in Henan in a period of 14 years. Although the overall incidence of PTB declined from 91.4/10⁵ to 58.5/10⁵, and the overall incidence of bacteriological-positive PTB declined from 44.5/10⁵ to 14.7/10⁵, the WHO’s 2025 goal could not be met. The distribution of high incidence and poverty-stricken counties were basically overlapped. Men, farmers and herdsmen (in rural areas), and subjects aged ≥60 years were more likely to develop bacteriological-positive PTB. The increasing treatment success for drug-susceptible tuberculosis and multidrug-resistant tuberculosis has not provided the desired reduction in incidence and mortality.

Conclusions

To achieve the targeted goal, while improving the cure rate of TB, new active (rather than passive) detection and intervention strategies should be formulated based on epidemiological characteristics in Henan province.

The impact of the Xpert MTB/RIF screening among hospitalized patients with pneumonia on timely isolation of patients with pulmonary tuberculosis

In South Korea where the tuberculosis (TB) burden is intermediate, the risk of in-hospital transmission of TB remains high. We conducted a retrospective cohort study of 244 inpatients diagnosed with pulmonary TB (2015–2018) to evaluate the impact of the Xpert MTB/RIF assay (Xpert) screening on timely isolation. TB screening was performed with smear microscopy and a polymerase chain reaction test, and the Xpert was additionally used from November 2016. Among all patients with pulmonary TB, the median time-to-isolation was significantly reduced (22.6 vs. 69.7 h; p < 0.001) and segmented regression analysis adjusting for the time trend showed a reduction in time-to-isolation with the introduction of the Xpert (− 39.3 h; 95% CI − 85.6, 7.0; p = 0.096). Among 213 patients who were timely screened (≤ 72 h after admission), time-to-isolation decreased significantly (− 38.2 h; 95% CI − 70.6, − 5.8; p = 0.021) with the introduction of the Xpert, and its decreasing trend continued. The Xpert provided a shorter turnaround time (4.8 vs. 49.1 h; p < 0.001) and higher sensitivity (76.6% vs. 47.8%; p < 0.001) than smear microscopy. Thus, the Xpert can be a useful screening test for pulmonary TB in real-life hospital settings with an intermediate TB burden.

Diabetes Mellitus and Its Associated Factors in Tuberculosis Patients in Maekel Region, Eritrea: Analytical Cross-Sectional Study

BACKGROUND

Both diabetes mellitus (DM) and tuberculosis (TB) are among the leading causes of morbidity and mortality in Eritrea. TB-DM comorbidity is known to complicate TB care, control and prevention. However, systematically studied epidemiological data on TB-DM comorbidity and its associated risk factors are lacking in this country.

OBJECTIVE

This study aimed to assess the prevalence of DM and its associated factors among TB patients in the Maekel region, Eritrea.

METHODS

Analytical cross-sectional study was conducted in eleven TB diagnostic and treatment sites. Pretested data extraction tool was used to collect data from medical records. Prevalence data were analysed using frequencies, proportions and median. To determine DM risk factors, univariable and multivariable logistic regression analysis was done with 95% CI and p value < 0.05 considered significant.

RESULTS

Out of total eligible (1134) TB cases, DM prevalence was 9.88%. Age and BMI were identified as independent risk factors for DM among TB patients. Higher odds of DM were found among TB patients aged 45-54 (aOR: 4.85[1.39-16.94], p= 0.013) and those ≥55 (aOR: 6.99[2.12-23.04], p= 0.001). TB cases with normal BMI were two times more likely to have DM (aOR: 2.00[1.23-3.26], p= 0.005) compared to those underweight.

CONCLUSION

The prevalence of DM among TB cases observed in this study is high, a clarion call to scale up current efforts to integrate TB-DM services within routine care. Furthermore, age and BMI were identified as independent risk factors for DM in TB cases, pointing to the need to pay attention to age and BMI status when managing this co-morbidity.

Knowledge, Perceived Beliefs, and Preventive Behaviors Related to COVID-19 Among Chinese Older Adults: Cross-Sectional Web-Based Survey

BACKGROUND

The COVID-19 pandemic continues to pose an international public health threat. Prevention is of paramount importance to protect the high-risk group of older adults until specific treatments for COVID-19 become available; however, little work has been done to explore factors that promote preventive behaviors among this population.

OBJECTIVE

This study aims to investigate the knowledge, perceived beliefs, and preventive behaviors towards COVID-19 of older adults in China and determine the factors that influence their practice of preventive behaviors.

METHODS

From February 19 to March 19, 2020, a cross-sectional, web-based survey was administered to Chinese older adults in all 31 provinces of mainland China using a convenience sampling method to assess the respondents' knowledge, perceived beliefs, and preventive behaviors towards COVID-19. Standard descriptive statistics and hierarchical linear regression analyses were conducted to analyze the data.

RESULTS

A total of 1501 participants responded to the survey, and 1263 valid responses (84.1%) were obtained for further analysis. The overall correct rate on the knowledge questionnaire was 87%, overall positive beliefs regarding COVID-19 were found, and the mean behavior score was 13.73/15 (SD 1.62, range 5-15). The hierarchical linear regression showed that respondents who were married or cohabitating and who lived in areas with community-level control measures were more likely to practice preventive behaviors (P<.01). Knowledge (β=0.198, P<.001), perceived susceptibility (β=0.263, P=.03), perceived benefits (β=0.643, P<.001), and self-efficacy in preventing COVID-19 (β=0.468, P<.001) were also found to be significantly associated with preventive behaviors.

CONCLUSIONS

Most older residents had adequate knowledge and positive beliefs regarding COVID-19 and engaged in proactive behaviors to prevent the disease. Knowledge and beliefs were confirmed to be significantly associated with behavior responses. Our findings have significant implications in enhancing the effectiveness of COVID-19 prevention programs targeting the older population; these programs must be continued and strengthened as the epidemic continues.

A research agenda for ageing in China in the 21st century (2nd edition): Focusing on basic and translational research, long-term care, policy and social networks

One of the key issues facing public healthcare is the global trend of an increasingly ageing society which continues to present policy makers and caregivers with formidable healthcare and socio-economic challenges. Ageing is the primary contributor to a broad spectrum of chronic disorders all associated with a lower quality of life in the elderly. In 2019, the Chinese population constituted 18 % of the world population, with 164.5 million Chinese citizens aged 65 and above (65+), and 26 million aged 80 or above (80+). China has become an ageing society, and as it continues to age it will continue to exacerbate the burden borne by current family and public healthcare systems. Major healthcare challenges involved with caring for the elderly in China include the management of chronic non-communicable diseases (CNCDs), physical frailty, neurodegenerative diseases, cardiovascular diseases, with emerging challenges such as providing sufficient dental care, combating the rising prevalence of sexually transmitted diseases among nursing home communities, providing support for increased incidences of immune diseases, and the growing necessity to provide palliative care for the elderly. At the governmental level, it is necessary to make long-term strategic plans to respond to the pressures of an ageing society, especially to establish a nationwide, affordable, annual health check system to facilitate early diagnosis and provide access to affordable treatments. China has begun work on several activities to address these issues including the recent completion of the of the Ten-year Health-Care Reform project, the implementation of the Healthy China 2030 Action Plan, and the opening of the National Clinical Research Center for Geriatric Disorders. There are also societal challenges, namely the shift from an extended family system in which the younger provide home care for their elderly family members, to the current trend in which young people are increasingly migrating towards major cities for work, increasing reliance on nursing homes to compensate, especially following the outcomes of the 'one child policy' and the 'empty-nest elderly' phenomenon. At the individual level, it is important to provide avenues for people to seek and improve their own knowledge of health and disease, to encourage them to seek medical check-ups to prevent/manage illness, and to find ways to promote modifiable health-related behaviors (social activity, exercise, healthy diets, reasonable diet supplements) to enable healthier, happier, longer, and more productive lives in the elderly. Finally, at the technological or treatment level, there is a focus on modern technologies to counteract the negative effects of ageing. Researchers are striving to produce drugs that can mimic the effects of 'exercising more, eating less', while other anti-ageing molecules from molecular gerontologists could help to improve 'healthspan' in the elderly. Machine learning, 'Big Data', and other novel technologies can also be used to monitor disease patterns at the population level and may be used to inform policy design in the future. Collectively, synergies across disciplines on policies, geriatric care, drug development, personal awareness, the use of big data, machine learning and personalized medicine will transform China into a country that enables the most for its elderly, maximizing and celebrating their longevity in the coming decades. This is the 2nd edition of the review paper (Fang EF et al., Ageing Re. Rev. 2015).

Safety of Pyrazinamide for the Treatment of Tuberculosis in Older Patients Over 75 Years of Age: A Retrospective Monocentric Cohort Study

OBJECTIVES

Pyrazinamide (PZA) has a controversial safety profile in older patients. We aimed to assess the frequency and risk factors for adverse drug reactions (ADRs) in patients over 75 years of age treated for tuberculosis with or without PZA.

METHODS

We conducted a retrospective monocentric study including patients aged over 75 years treated for active tuberculosis between 2008 and 2018. The frequency, type, seriousness, and causality assessment of ADRs to anti-tuberculosis treatment were compared between patients receiving PZA or not. Risk factors for ADRs were investigated using univariable and multivariable analyses by logistic regression.

RESULTS

Among the 110 patients included, 54 (49.1%) received PZA (group 1) and 56 (50.9%) did not (group 2). ADRs to anti-tuberculosis drugs occurred in 31 patients (57.4%) in groups 1 and 15 (26.8%) in group 2 (p = 0.003). PZA-related ADRs occurred in 40.7% of exposed patients. Frequency of renal ADRs was higher in group 1 (9.3% vs 0%; p = 0.026). Rates of hepatic (18.5% vs 12.5%; p = 0.38), digestive (22.2% vs 8.9%; p = 0.054), and allergic (14.8% vs 5.4%; p = 0.12) ADRs were numerically higher in group 1 although the differences were not statistically significant. Serious ADRs occurred more frequently in group 1 (24.1% vs 8.9%; p = 0.03). The use of PZA was the only independent risk factor for ADRs to anti-tuberculosis drugs (odds ratio 3.75, 95% CI 1.5-9.6; p = 0.0056). No risk factors for PZA-related ADRs were identified.

CONCLUSION

In older French patients, the use of PZA was associated with more frequent ADRs to anti-tuberculosis drugs.

Potential impact of tuberculosis vaccines in China, South Africa, and India

More effective tuberculosis vaccines are needed to help reach World Health Organization tuberculosis elimination goals. Insufficient evidence exists on the potential impact of future tuberculosis vaccines with varying characteristics and in different epidemiological settings. To inform vaccine development decision making, we modeled the impact of hypothetical tuberculosis vaccines in three high-burden countries. We calibrated Mycobacterium tuberculosis (M.tb) transmission models to age-stratified demographic and epidemiological data from China, South Africa, and India. We varied vaccine efficacy to prevent infection or disease, effective in persons M.tb uninfected or infected, and duration of protection. We modeled routine early-adolescent vaccination and 10-yearly mass campaigns from 2025. We estimated median percentage population-level tuberculosis incidence rate reduction (IRR) in 2050 compared to a no new vaccine scenario. In all settings, results suggested vaccines preventing disease in M.tb-infected populations would have greatest impact by 2050 (10-year, 70% efficacy against disease, IRR 51%, 52%, and 54% in China, South Africa, and India, respectively). Vaccines preventing reinfection delivered lower potential impact (IRR 1, 12, and 17%). Intermediate impact was predicted for vaccines effective only in uninfected populations, if preventing infection (IRR 21, 37, and 50%) or disease (IRR 19, 36, and 51%), with greater impact in higher-transmission settings. Tuberculosis vaccines have the potential to deliver substantial population-level impact. For prioritizing impact by 2050, vaccine development should focus on preventing disease in M.tb-infected populations. Preventing infection or disease in uninfected populations may be useful in higher transmission settings. As vaccine impact depended on epidemiology, different development strategies may be required.

Prediction of treatment failure and compliance in patients with tuberculosis

Background

To improve treatment outcomes for tuberculosis (TB), efforts to reduce treatment failure are necessary. The aim of our study was to describe the characteristics of subjects who had failed treatment of tuberculosis and identify the risk factors for treatment failure and poor compliance using national data.

Methods

A multicenter cross-sectional study was performed on tuberculosis subjects whose final outcome was reported as treatment failure during 2015–2017. The same number of subjects with treatment success during the same study period were randomly selected for comparison. Demographics, microbiological, radiographic, and clinical data were collected based on in-depth interviews by TB nurse specialists at all Public Private Mix (PPM) participating hospitals in South Korea.

Results

A total of 52 tuberculosis patients with treatment failure were enrolled. In a multivariable analysis, the presence of diabetes, previous history of tuberculosis, and cavity were identified as risk factors for treatment failure; and Medicaid support was a favorable factor for treatment success (area under the curve [AUC]: 0.79). Age, low body mass index (BMI), presence of diabetes, preexisting lung disease, positive sputum acid-fast bacilli (AFB) smear result, and the presence of multidrug-resistant tuberculosis (MDR-TB) were significantly associated with presence of cavities. Younger age, lower BMI and previous history of TB were associated with poor compliance during treatment (AUC: 0.76).

Conclusion

To reduce treatment failure, careful evaluation of the presence of diabetes, previous TB history, underlying lung disease, cavity, results of sputum AFB smears, and socioeconomic status are needed. To enhance treatment compliance, more attention should be paid to younger patients with lower BMIs during follow-up.

Active Pulmonary Tuberculosis in Elderly Patients: A 2016-2019 Retrospective Analysis from an Italian Referral Hospital

Tuberculosis (TB) in the elderly (>65 years old) has increasingly become a global health problem. It has long been recognized that older people are vulnerable to developing tuberculosis. We retrospectively evaluated data from patients older than 65 years diagnosed with pulmonary TB admitted to the National Institute for Infectious Diseases L. Spallanzani, Rome, Italy, from 1 January 2016 to 31 December 2019. One hundred and six consecutive patients were diagnosed with pulmonary TB and 68% reported at least one comorbidity and 44% at least one of the TB risk-factors. Out of the 26 elderly patients who reported an adverse event, having risk factors for TB (O.R. (Odds Ratios) = 1.45; 95% CI 1.12-3.65) and the presence of cavities on Chest X-rays (O.R. = 1.42; 95% CI 1.08-2.73) resulted in being more likely to be associated with adverse events in elderly patients. Having weight loss (O.R. = 1.31; 95% CI 1.08-1.55) and dyspnea (O.R. = 1.23; 95% CI 1.13-1.41) resulted in being significant predictors of unsuccessful treatment outcome in elderly patients. Older people with TB represent a vulnerable group, with high mortality rate, with a challenging diagnosis. Hospitalizations in tertiary referral hospital with clinical expertise in TB management can be useful to improve the outcome of these fragile patients.

BCG vaccine protection from severe coronavirus disease 2019 (COVID-19)

A series of epidemiological explorations has suggested a negative association between national bacillus Calmette-Guérin (BCG) vaccination policy and the prevalence and mortality of coronavirus disease 2019 (COVID-19). However, these comparisons are difficult to validate due to broad differences between countries such as socioeconomic status, demographic structure, rural vs. urban settings, time of arrival of the pandemic, number of diagnostic tests and criteria for testing, and national control strategies to limit the spread of COVID-19. We review evidence for a potential biological basis of BCG cross-protection from severe COVID-19, and refine the epidemiological analysis to mitigate effects of potentially confounding factors (e.g., stage of the COVID-19 epidemic, development, rurality, population density, and age structure). A strong correlation between the BCG index, an estimation of the degree of universal BCG vaccination deployment in a country, and COVID-19 mortality in different socially similar European countries was observed (r2 = 0.88; P = 8 × 10-7), indicating that every 10% increase in the BCG index was associated with a 10.4% reduction in COVID-19 mortality. Results fail to confirm the null hypothesis of no association between BCG vaccination and COVID-19 mortality, and suggest that BCG could have a protective effect. Nevertheless, the analyses are restricted to coarse-scale signals and should be considered with caution. BCG vaccination clinical trials are required to corroborate the patterns detected here, and to establish causality between BCG vaccination and protection from severe COVID-19. Public health implications of a plausible BCG cross-protection from severe COVID-19 are discussed.