[Disseminated infection caused by the bacillus Calmette-Guérin vaccine and SARS-CoV-2 coinfection in a patient with IL-12 receptor ß1 subunit deficiency]. / Infección diseminada por vacuna con bacilo de Calmette-Guérin y coinfección por SARS-CoV-2 en paciente con deficiencia de la subunidad ß1 del receptor de IL-12.

BACKGROUND: Inborn errors of immunity manifest with a greater susceptibility to infections, autoimmunity, autoinflammatory diseases, allergies, or malignancies. One of these is the mendelian susceptibility to mycobacterial disease. The most frequent etiology is the complete autosomal recessive deficiency of the ß1 subunit of the interleukin 12 receptor. CASE REPORT: A female patient who, by the age of six months, started with a nodular lesion in the right shoulder and ipsilateral axillary adenitis after the bacillus Calmette-Guérin vaccine was applied. Later, she developed a cutaneous fistula in the anterior thorax, the inframammary region, and chronic recidivant suppurative lymphadenitis. A disseminated infection caused by Mycobacterium bovis was diagnosed, therefore, individualized pharmacological treatment was required due to failure with the primary treatment. The patient was diagnosed with deficiency in the ß1 subunit of the interleukin 12 receptor at age six. During her last hospitalization, she presented fever, cough, and tachypnea, and SARS-CoV-2 was detected by quantitative polymerase chain reaction. The patient has had a favorable evolution. CONCLUSION: In patients with disseminated infections caused by bacillus Calmette-Guérin vaccination or by environmental mycobacteria, there should be suspicion of an inborn error of immunity and the patient should be referred to a third level hospital for an early immunological assessment.

Antecedentes: Los errores innatos de la inmunidad se manifiestan con una mayor susceptibilidad a infecciones, autoinmunidad, enfermedades autoinflamatorias, alergia o malignidad. Uno de estos es la susceptibilidad mendeliana a infecciones micobacterianas. La etiología más frecuente es la deficiencia completa autosómica recesiva de la subunidad ß1 del receptor de interleucina 12. Caso clínico: Paciente que comenzó a los seis meses de edad con una lesión nodular en hombro derecho y adenitis axilar ipsolateral posterior a la vacuna con bacilo de Calmette-Guérin. Posteriormente desarrolló una fistula cutánea en tórax anterior, región inframamaria y linfadenitis supurativa crónica recidivante. Se diagnosticó infección diseminada por Mycobacterium bovis, por lo que requirió tratamiento farmacológico individualizado debido al fracaso con el tratamiento primario. La paciente fue diagnosticada con deficiencia de la subunidad ß1 del receptor de interleucina 12 a los seis años. Durante su última hospitalización presentó fiebre, tos y taquipnea, detectándose SARS-CoV-2 por reacción en cadena de la polimerasa cuantitativa. La paciente evolucionó favorablemente. Conclusión: En los pacientes con infecciones diseminadas por la vacuna con bacilo de Calmette-Guérin o micobacterias ambientales, debe sospecharse un error innato de la inmunidad y derivarlos a tercer nivel de atención para la evaluación inmunológica temprana.

Recombinant Bacillus Calmette-Guérin Expressing SARS-CoV-2 Chimeric Protein Protects K18-hACE2 Mice against Viral Challenge.

COVID-19 has accounted for more than 6 million deaths worldwide. Bacillus Calmette-Guérin (BCG), the existing tuberculosis vaccine, is known to induce heterologous effects over other infections due to trained immunity and has been proposed to be a potential strategy against SARS-CoV-2 infection. In this report, we constructed a recombinant BCG (rBCG) expressing domains of the SARS-CoV-2 nucleocapsid and spike proteins (termed rBCG-ChD6), recognized as major candidates for vaccine development. We investigated whether rBCG-ChD6 immunization followed by a boost with the recombinant nucleocapsid and spike chimera (rChimera), together with alum, provided protection against SARS-CoV-2 infection in K18-hACE2 mice. A single dose of rBCG-ChD6 boosted with rChimera associated with alum elicited the highest anti-Chimera total IgG and IgG2c Ab titers with neutralizing activity against SARS-CoV-2 Wuhan strain when compared with control groups. Importantly, following SARS-CoV-2 challenge, this vaccination regimen induced IFN-γ and IL-6 production in spleen cells and reduced viral load in the lungs. In addition, no viable virus was detected in mice immunized with rBCG-ChD6 boosted with rChimera, which was associated with decreased lung pathology when compared with BCG WT-rChimera/alum or rChimera/alum control groups. Overall, our study demonstrates the potential of a prime-boost immunization system based on an rBCG expressing a chimeric protein derived from SARS-CoV-2 to protect mice against viral challenge.

Multisystem inflammatory syndrome in children associated with Bacille Calmette-Guérin scar: a case presentation.

BACKGROUND: During Coronavirus disease of 2019 (COVID-19) pandemic, the WHO reported a noticeable increase in Kawasaki disease prevalence in countries where Kawasaki disease is rare. This newly seen disease, unlike typical Kawasaki disease, tends to appear at a later age, has prominent gastrointestinal findings, higher rates of myocarditis and coronary artery involvement and a greater need for admission to the intensive care unit (ICU). Induration of the Bacillus Calmette-Guerin (BCG) scar is a rare finding seen in multisystem inflammatory syndrome (MIS-C). This is the second reported case of erythema and induration of the BCG scar in a 1-year-old boy with MIS-C. CASE PRESENTATION: The Arabic boy presented with high resistant fever, nausea/vomiting, diarrhea, erythematous lips, and conjunctivitis. He later developed induration of his BCG scar, diffuse rash and desquamation on fingers and toes. He had a history of COVID-19 exposure as his IgG antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were positive. Based on his clinical findings and repeated lab results, he was diagnosed with MIS-C with Kawasaki features and treated with intravenous immune globulin (IVIG) followed by methylprenisolone and aspirin. CONCLUSIONS: Reaction at the BCG inoculation site is not a diagnostic criteria for Kawasaki, but it is seen clinically in 30-50% of the patients. We report the case of a 1-year-old boy diagnosed with MIS-C presenting with erythema and induration of BCG scar. Further studies are needed to explore this clinical presentation, especially in the countries that have BCG vaccination programs, and to determine the mechanisms of MIS-C.

The effect of BCG vaccination on infection and antibody levels against SARS-CoV-2-The results of ProBCG: a multicenter randomized clinical trial in Brazil.

OBJECTIVES: Evatuate if Bacillus Calmette-Guérin (BCG) vaccine could be used as a tool against SARS-CoV-2 based on the concept of trained immunity. METHODS: A multicenter, double-blinded, randomized clinical trial recruited health care workers (HCWs) in Brazil. The incidence rates of COVID-19, clinical manifestations, absenteeism, and adverse events among HCWs receiving BCG vaccine (Moreau or Moscow strains) or placebo were compared. BCG vaccine-mediated immune response before and after implementing specific vaccines for COVID-19 (CoronaVac or COVISHIELD) was analyzed. Cox proportional hazard and linear mixed effect modeling were used. RESULTS: A total of 264 volunteers were included for analysis (BCG = 134 and placebo = 130). The placebo group presented a COVID-19 cumulative incidence of 0.75% vs 0.52% of BCG. The Moreau strain also presented a higher incidence rate (1.60% × 0.22%). BCG did not show a protective hazard ratio against COVID-19. In addition, the log (immunoglobulin G) level against SARS-CoV-2 presented a higher increase in the BCG group, whether or not participants had COVID-19, but also without statistical significance. CONCLUSION: Our results suggest that BCG has a tendency of protection against SARS-CoV-2 and higher immunoglobulin G levels than placebo. The clinical trial was registered at https://clinicaltrials.gov/ (NCT04659941).

BCG-induced trained immunity: history, mechanisms and potential applications.

The Bacillus Calmette-Guérin (BCG) vaccine was discovered a century ago and has since been clinically applicable. BCG can not only be used for the prevention of tuberculosis, but also has a non-specific protective effect on the human body called trained immunity that is mediated by innate immune cells such as monocytes, macrophages, and natural killer cells. Mechanisms of trained immunity include epigenetic reprogramming, metabolic reprogramming, and long-term protection mediated by hematopoietic stem cells. Trained immunity has so far shown beneficial effects on cancer, viral-infections, autoimmune diseases, and a variety of other diseases, especially bladder cancer, respiratory viruses, and type 1 diabetes. The modulation of the immune response by BCG has led to the development of a variety of recombinant vaccines. Although the specific mechanism of BCG prevention on diseases has not been fully clarified, the potential role of BCG deserves further exploration, which is of great significance for prevention and treatment of diseases.

The impact of circadian rhythm on Bacillus Calmette-Guérin vaccination effects on SARS-CoV-2 infections.

Background and objective: A recent study has suggested that circadian rhythm has an important impact on the immunological effects induced by Bacillus Calmette-Guérin (BCG) vaccination. The objective of this study was to evaluate whether the timing of BCG vaccination (morning or afternoon) affects its impact on severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infections and clinically relevant respiratory tract infections (RTIs). Methods: This is a post-hoc analysis of the BCG-CORONA-ELDERLY (NCT04417335) multicenter, placebo-controlled trial, in which participants aged 60 years and older were randomly assigned to vaccination with BCG or placebo, and followed for 12 months. The primary endpoint was the cumulative incidence of SARS-CoV-2 infection. To assess the impact of circadian rhythm on the BCG effects, participants were divided into four groups: vaccinated with either BCG or placebo in the morning (between 9:00h and 11:30h) or in the afternoon (between 14:30h and 18:00h). Results: The subdistribution hazard ratio of SARS-CoV-2 infection in the first six months after vaccination was 2.394 (95% confidence interval [CI], 0.856-6.696) for the morning BCG group and 0.284 (95% CI, 0.055-1.480) for the afternoon BCG group. When comparing those two groups, the interaction hazard ratio was 8.966 (95% CI, 1.366-58.836). In the period from six months until 12 months after vaccination cumulative incidences of SARS-CoV-2 infection were comparable, as well as cumulative incidences of clinically relevant RTI in both periods. Conclusion: Vaccination with BCG in the afternoon offered better protection against SARS-CoV-2 infections than BCG vaccination in the morning in the first six months after vaccination.

Trained Immunity, BCG and SARS-CoV-2 General Outline and Possible Management in COVID-19.

The Bacillus Calmette-Guérin (BCG) vaccine has been in use for over 100 years. It protects against severe, blood-borne forms of tuberculosis. Observations indicate that it also increases immunity against other diseases. The mechanism responsible for this is trained immunity, an increased response of non-specific immune cells in repeated contact with a pathogen, not necessarily of the same species. In the following review, we present the current state of knowledge on the molecular mechanisms responsible for this process. We also seek to identify the challenges facing science in this area and consider the application of this phenomenon in managing the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic.

Effects of intravesical BCG maintenance therapy duration on recurrence rate in high-risk non-muscle invasive bladder cancer (NMIBC): Systematic review and network meta-analysis according to EAU COVID-19 recommendations.

PURPOSE: During the coronavirus disease 2019 (COVID-19) pandemic, the European Association of Urology (EAU) recommended that courses of intravesical bacillus Calmette-Guérin (BCG) therapy lasting more than 1 year could be safely terminated for patients with high-risk non-muscle-invasive bladder cancer (NMIBC). Thus, we conducted a systematic review and network meta-analysis according to EAU's COVID-19 recommendations. MATERIALS AND METHODS: A systematic review was performed following the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. We conducted a network meta-analysis of recurrence rate in patients with NMIBC receiving induction therapy (M0) and those receiving maintenance therapy lasting 1 year (M1) and more than 1 year (M2). RESULTS: Nineteen studies of 3,957 patients were included for the network meta-analysis. In a node-split forest plot using Bayesian Markov Chain Monte Carlo (MCMC) modeling, there were no differences between the M1 and M2 groups in recurrence rate [odds ratio (OR) 0.95 (0.73-1.2)]. However, recurrence rate in the M0 group was higher than that in the M1 [OR 1.9 (1.5-2.5)] and M2 [OR 2.0 (1.7-2.4)] groups. P-score tests using frequentist inference to rank the treatments in the network demonstrated that the therapy used in the M2 group (P-score 0.8701) was superior to that used in the M1 (P-score 0.6299) and M0 groups (P-score 0). In rank-probability tests using MCMC modeling, the M2 group showed the highest rank, followed by the M1 and M0 groups. CONCLUSION: In the network meta-analysis, there were no differences between those receiving BCG maintenance therapies in terms of recurrence rate. In the rank tests, therapy lasting more than 1-year appears to be most effective. During the COVID-19 pandemic, 1-year maintenance therapy can be used, but after the COVID-19 pandemic, therapy lasting more than 1-year could be beneficial.

Prevalence and molecular characterization of Mycobacterium tuberculosis complex in cattle and humans, Maiduguri, Borno state, Nigeria: a cross-sectional study.

INTRODUCTION: Globally, the highest burden of bovine and human tuberculosis resides in Africa and Asia. Tuberculosis (TB) is the second leading single infectious killer after severe acute respiratory syndrome corona virus-2 (SARSCOV-2). Bovine TB remains a treat to wild and domesticated animals, humans and hinders international trade in endemic countries like Nigeria. We aimed at determining the prevalence of bovine and human tuberculosis, and the spoligotypes of Mycobacterium tuberculosis complex in cattle and humans in Maiduguri. METHODS: We conducted a cross sectional study on bovine and human tuberculosis in Maiduguri, Borno state. We calculated sample size using the method of Thrusfield. Lesions suggestive of TB from 160 slaughtered cattle were obtained from Maiduguri Central Abattoir. Sputum samples from humans; 82 abattoir workers and 147 suspected TB patients from hospitals/clinics were obtained. Lesions and sputum samples were cultured for the isolation of Mycobacterium spp. Positive cultures were subjected genus typing, deletion analysis and selected isolates were spoligotyped. Data was analysed using SPSS VERSION 16.0. RESULTS: Prevalence of 32.5% (52/160) was obtained in cattle. Damboa local government area (LGA), where majority of the infected animals were obtained from had 35.5% bTB prevalence. All categories analysed (breed, age, sex, body conformation and score) had P-values that were not significant (P > 0.05). Sputum culture revealed a prevalence of 3.7% (3/82) from abattoir workers and 12.2% from hospitals/clinics. A significant P-value (0.03) was obtained when positive culture from abattoir and that of hospitals/clinics were compared. Out of the 52 culture positive isolates obtained from cattle, 26 (50%) belonged to M. tuberculosis complex (MTC) and 17/26 (65.4%) were characterized as M. bovis. In humans, 7/12 (58.3%) MTC obtained were characterized as M. tuberculosis. Spoligotyping revealed SB0944 and SB1025 in cattle, while SIT838, SIT61 of LAM10_CAM and SIT1054, SIT46 of Haarlem (H) families were obtained from humans. CONCLUSIONS: Cattle in Damboa LGA need to be screened for bTB as majority of the infected animals were brought from there. Our findings revealed the presence of SB0944 and SB1025 spoligotypes from cattle in Borno state. We isolated M. tuberculosis strain of the H family mainly domiciled in Europe from humans.

Superinfection with SARS-CoV-2 Has Deleterious Effects on Mycobacterium bovis BCG Immunity and Promotes Dissemination of Mycobacterium tuberculosis.

An estimated one-third of the world's population is infected with Mycobacterium tuberculosis, with the majority being vaccinated with Mycobacterium bovis BCG. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains a threat, and we must understand how SARS-CoV-2 can modulate both BCG immunity and tuberculosis pathogenesis. Interestingly, neither BCG vaccination nor tuberculosis infection resulted in differences in clinical outcomes associated with SARS-CoV-2 in transgenic mice. Surprisingly, earlier M. tuberculosis infection resulted in lower SARS-CoV-2 viral loads, mediated by the heightened immune microenvironment of the murine lungs, unlike vaccination with BCG, which had no impact. In contrast, M. tuberculosis-infected tissues had increased bacterial loads and decreased histiocytic inflammation in the lungs following SARS-CoV-2 superinfection. SARS-CoV-2 modulated BCG-induced type 17 responses while decreasing type 1 and increasing type 2 cytokines in M. tuberculosis-infected mice. These findings challenge initial findings of BCG's positive impact on SARS-CoV-2 infection and suggest potential ramifications for M. tuberculosis reactivation upon SARS-CoV-2 superinfection. IMPORTANCE Prior to SARS-CoV-2, M. tuberculosis was the leading infectious disease killer, with an estimated one-third of the world's population infected and 1.7 million deaths a year. Here, we show that SARS-CoV-2 superinfection caused increased bacterial dissemination in M. tuberculosis-infected mice along with immune and pathological changes. SARS-CoV-2 also impacted the immunity of BCG-vaccinated mice, resulting in decreased interleukin-17 (IL-17) levels, while offering no protective effect against SARS-CoV-2. These results demonstrate that SARS-CoV-2 may have a deleterious effect on the ongoing M. tuberculosis pandemic and potentially limit BCG's efficacy.

A century of BCG vaccination: Immune mechanisms, animal models, non-traditional routes and implications for COVID-19.

Bacillus Calmette-Guerin (BCG) has been used as a vaccine against tuberculosis since 1921 and remains the only currently approved vaccine for this infection. The recent discovery that BCG protects against initial infection, and not just against progression from latent to active disease, has significant implications for ongoing research into the immune mechanisms that are relevant to generate a solid host defense against Mycobacterium tuberculosis (Mtb). In this review, we first explore the different components of immunity that are augmented after BCG vaccination. Next, we summarize current efforts to improve the efficacy of BCG through the development of recombinant strains, heterologous prime-boost approaches and the deployment of non-traditional routes. These efforts have included the development of new recombinant BCG strains, and various strategies for expression of important antigens such as those deleted during the M. bovis attenuation process or antigens that are present only in Mtb. BCG is typically administered via the intradermal route, raising questions about whether this could account for its apparent failure to generate long-lasting immunological memory in the lungs and the inconsistent level of protection against pulmonary tuberculosis in adults. Recent years have seen a resurgence of interest in the mucosal and intravenous delivery routes as they have been shown to induce a better immune response both in the systemic and mucosal compartments. Finally, we discuss the potential benefits of the ability of BCG to confer trained immunity in a non-specific manner by broadly stimulating a host immunity resulting in a generalized survival benefit in neonates and the elderly, while potentially offering benefits for the control of new and emerging infectious diseases such as COVID-19. Given that BCG will likely continue to be widely used well into the future, it remains of critical importance to better understand the immune responses driven by it and how to leverage these for the design of improved vaccination strategies against tuberculosis.

Highlights of the 3rd international BCG symposium: 100th anniversary of the first administration of BCG.

2021 was the year of the 100th anniversary of the first administration of the Bacillus Calmette-Guérin (BCG) to a human being. It was the start of a long journey of the world's most widely used vaccine and the oldest vaccine still in use. More than 4 billion children have been vaccinated with BCG for protection against tuberculosis. However, over the years it became apparent that BCG also has beneficial non-specific effects. As such, it provides protection against various heterologous infectious and non-infectious diseases and is used to treat non-muscle-invasive bladder cancer. As BCG was developed at the Institut Pasteur de Lille by Albert Calmette and Camille Guérin, the Institute has celebrated this important anniversary with an international scientific symposium on all aspects of BCG, held from November 17 to 19, 2021 at the Institut Pasteur de Lille. It covered BCG against tuberculosis and described novel vaccine approaches, the effect of BCG against heterologous infections, including BCG and COVID-19, the effect of BCG against cancer, and BCG against auto-immune and inflammatory diseases. To discuss these areas, the symposium gathered close to 200 participants from all five continents, 2/3 on-line. This article presents the highlights of this 3rd International Symposium on BCG.

Multiple BCG vaccinations for the prevention of COVID-19 and other infectious diseases in type 1 diabetes.

There is a need for safe and effective platform vaccines to protect against coronavirus disease 2019 (COVID-19) and other infectious diseases. In this randomized, double-blinded, placebo-controlled phase 2/3 trial, we evaluate the safety and efficacy of a multi-dose Bacillus Calmette-Guérin (BCG) vaccine for the prevention of COVID-19 and other infectious disease in a COVID-19-unvaccinated, at-risk-community-based cohort. The at-risk population is made of up of adults with type 1 diabetes. We enrolled 144 subjects and randomized 96 to BCG and 48 to placebo. There were no dropouts over the 15-month trial. A cumulative incidence of 12.5% of placebo-treated and 1% of BCG-treated participants meets criteria for confirmed COVID-19, yielding an efficacy of 92%. The BCG group also displayed fewer infectious disease symptoms and lesser severity and fewer infectious disease events per patient, including COVID-19. There were no BCG-related systemic adverse events. BCG's broad-based infection protection suggests that it may provide platform protection against new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants and other pathogens.

Bacillus Calmette-Guérin vaccine to reduce healthcare worker absenteeism in COVID-19 pandemic, a randomized controlled trial.

OBJECTIVES: The COVID-19 pandemic increases healthcare worker (HCW) absenteeism. The bacillus Calmette-Guérin (BCG) vaccine may provide non-specific protection against respiratory infections through enhancement of trained immunity. We investigated the impact of BCG vaccination on HCW absenteeism during the COVID-19 pandemic. METHODS: HCWs exposed to COVID-19 patients in nine Dutch hospitals were randomized to BCG vaccine or placebo in a 1:1 ratio, and followed for one year using a mobile phone application. The primary endpoint was the self-reported number of days of unplanned absenteeism for any reason. Secondary endpoints included documented COVID-19, acute respiratory symptoms or fever. This was an investigator-funded study, registered at ClinicalTrials.gov (NCT03987919). RESULTS: In March/April 2020, 1511 HCWs were enrolled. The median duration of follow-up was 357 person-days (interquartile range [IQR], 351 to 361). Unplanned absenteeism for any reason was observed in 2.8% of planned working days in the BCG group and 2.7% in the placebo group (adjusted relative risk 0.94; 95% credible interval, 0.78-1.15). Cumulative incidences of documented COVID-19 were 14.2% in the BCG and 15.2% in the placebo group (adjusted hazard ratio (aHR) 0.94; 95% confidence interval (CI), 0.72-1.24). First episodes of self-reported acute respiratory symptoms or fever occurred in 490 (66.2%) and 443 (60.2%) participants, respectively (aHR: 1.13; 95% CI, 0.99-1.28). Thirty-one serious adverse events were reported (13 after BCG, 18 after placebo), none considered related to study medication. CONCLUSIONS: During the COVID-19 pandemic, BCG-vaccination of HCW exposed to COVID-19 patients did not reduce unplanned absenteeism nor documented COVID-19.

Tuberculosis vaccines in the era of Covid-19 - what is taking us so long?

The Mycobacterium bovis BCG vaccine was first used in 1921, but has not controlled the global spread of tuberculosis (TB). There are still no new licensed tuberculosis vaccines, although there much active research and a vaccine development pipeline, with vaccines designed to prevent infection, prevent disease, or accelerate TB treatment. These vaccines are of different types, and designed to replace BCG, or to boost immunity following BCG vaccination. This viewpoint discusses why, when it has been possible to develop new vaccines for SARS-CoV-2 so quickly, it is taking so long to develop new tuberculosis vaccines.

Efficacy and Safety of BCG Revaccination With M. bovis BCG Moscow to Prevent COVID-19 Infection in Health Care Workers: A Randomized Phase II Clinical Trial.

The Bacillus Calmette-Guérin (BCG) vaccine, which is widely used to protect children against tuberculosis, can also improve immune response against viral infections. This unicentric, randomized-controlled clinical trial assessed the efficacy and safety of revaccination with BCG Moscow in reducing the positivity and symptoms of COVID-19 in health care workers (HCWs) during the COVID-19 pandemic. HCWs who had negative COVID-19 IgM and IgG and who dedicated at least eight hours per week in facilities that attended to individuals suspected of having COVID-19 were included in the study and were followed for 7, 15, 30, 60, and 180 days by telemedicine. The HCWs were randomly allocated to a revaccinated with BCG group, which received the BCG vaccine, or an unvaccinated group. Revaccination with BCG Moscow was found to be safe, and its efficacy ranged from 30.0% (95.0%CI -78.0 to 72.0%) to 31.0% (95.0%CI -74.0 to 74.0%). Mycobacterium bovis BCG Moscow did not induce NK cell activation at 15-20 days post-revaccination. As hypothesized, revaccination with BCG Moscow was associated with a lower incidence of COVID-19 positivity, though the results did not reach statistical significance. Further studies should be carried out to assess whether revaccination with BCG is able to protect HCWs against COVID-19. The protocol of this clinical trial was registered on August 5th, 2020, at REBEC (Registro Brasileiro de Ensaios Clínicos, RBR-4kjqtg - ensaiosclinicos.gov.br/rg/RBR-4kjqtg/1) and the WHO (# U1111-1256-3892). The clinical trial protocol was approved by the Comissão Nacional de ética de pesquisa- CONEP (CAAE 31783720.0.0000.5078).

BCG vaccination strategies against tuberculosis: updates and perspectives.

Bacillus Calmette-Guérin (BCG) is the only licensed vaccine against tuberculosis (TB). However, BCG has variable efficacy and cannot completely prevent TB infection and transmission. Therefore, the worldwide prevalence of TB calls for urgent development of a more effective TB vaccine. In the absence of other approved vaccines, it is also necessary to improve the efficacy of BCG itself. Intravenous (IV) BCG administration and BCG revaccination strategies have recently shown promising results for clinical usage. Therefore, it is necessary for us to revisit the BCG vaccination strategies and summarize the current research updates related to BCG vaccination. This literature review provides an updated overview and perspectives of the immunization strategies against TB using BCG, which may inspire the following research on TB vaccine development.

Exploring the role of bacillus calmette-guerin vaccination in protection against COVID-19.

BACKGROUND: In recent studies, it has been established that countries having Bacillus Calmette-Guerin (BCG) vaccination programs reported less COVID-19 cases and deaths per population Preliminary studies suggest that BCG vaccination could upregulate the vaccine-induced immunity against SARS-CoV-2. Hence, the recent study was aimed to determine the association of BCG vaccine with the development of COVID-19 in health care workers. METHODS: The participants included in the study were healthcare workers (doctors, paramedics, and other supporting staff) working in the high and low-risk zones of COVID-19 in the hospital. The Graph Pad statistical analysis tool was used to determine the association of preliminary BCG vaccination with their COVID-19 status. RESULTS: A total of 200 health care workers working in different departments of the hospital were enrolled in the study. The relative risk of COVID-19 positivity in BCG vaccinated versus unvaccinated was 0.79 (0.50-1.25). There was also a significant negative correlation between two groups. The relative risk of COVID-19 positivity in those with a BCG scar was 0.63 (0.44-0.92). The relative risk of COVID-19 infection in those with a history of tuberculosis was 1.08 (0.56-2.09). CONCLUSION: The present study did not support the beneficial effect of BCG vaccine in protection against the development of COVID-19 disease.

miR-495 Regulates Cellular Reactive Oxygen Species Levels by Targeting sod2 To Inhibit Intracellular Survival of Mycobacterium tuberculosis in Macrophages.

Mycobacterium tuberculosis is a chronic infectious disease pathogen. To date, tuberculosis is a major infectious disease that endangers human health. To better prevent and treat tuberculosis, it is important to study the pathogenesis of M. tuberculosis. Based on early-stage laboratory research results, in this study, we verified the upregulation of sod2 in Bacillus Calmette-Guérin (BCG) and H37Rv infection. By detecting BCG/H37Rv intracellular survival in sod2-silenced and sod2-overexpressing macrophages, sod2 was found to promote the intracellular survival of BCG/H37Rv. miR-495 then was determined to be downregulated by BCG/H37Rv. BCG/H37Rv can upregulate sod2 expression by miR-495 to promote the intracellular survival of BCG/H37Rv through a decline in ROS levels. This study provides a theoretical basis for developing new drug targets and treating tuberculosis.