Objectives The BCG vaccine, widely used in Brazil in new-borns, induces adjuvant protection for several diseases, including childhood virus infections. BCG activates monocytes and innate memory NK cells which are crucial for the antiviral immune response. Therefore, strategies to prevent COVID-19 in health workers (HW) should be carried out to prevent them becoming unwell so that they can continue to work during the pandemic. The hypothesis is that BCG will improve the innate immune response and prevent symptomatic infection or COVID-19 severity. The primary objective is to verify the effectiveness and safety of the BCG vaccine to prevent or reduce incidence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection in the city of Goiânia (Brazil) among HW previously vaccinated with BCG and also its severity and mortality during the pandemic of the disease. Secondary objectives are to estimate the incidence of COVID-19 among these professionals and the innate immune response elicited to BCG. Trial design This a phase II trial for repositioning BCG as a preventive strategy against COVID-19. The trial is an open-label, parallel-group randomised clinical trial, comparing HW vaccinated with BCG and HW not vaccinated. Participants The trial will recruit 800 HW of Goiânia - Goiás, Brazil to reach a total of 400 HW included after comorbidities questioning and laboratorial evaluation. Eligibility criteria: Any HW presenting BCG vaccination scar with direct contact with suspected COVID-19 patients for at least 8 hours per week, whether in hospital beds, ICU, or in transportation or admission (nurses, doctors, physiotherapists, nutritionists, receptionists, etc.) who have negative IgM and IgG COVID-19 test. Participants with any of the following characteristics will be excluded: - Have had in the last fifteen days any signs or symptoms of virus infection, including COVID-19; - Have had fever in the last fifteen days; - Have been vaccinated fifteen days before the inclusion; - Have a history or confirmation of any immunosuppressive disease such as HIV, presented solid tumour in the last two years or autoimmune diseases; - Are under preventive medication with antibiotics, steroid anti-inflammatories, or chemotherapy; - Have less than 500 neutrophils per mL of blood; - Have previously been diagnosed with tuberculosis; - Are breastfeeding or pregnant; - Are younger than 18 years old; - Are participating as an investigator in this clinical trial. Intervention and comparator HW will be randomized into the BCG vaccinated group or the BCG unvaccinated control group. The BCG vaccinated group will receive in the right arm, intradermally, a one off dose of 0.1 mL corresponding to approximately 2 x105 to 8 x105 CFU of live, freeze-dried, attenuated BCG Moscow 361-I, Bacillus Calmette Guerin vaccine (Serum Institute of India PVT. LTD.). The unvaccinated control group will not be vaccinated. The HW allocated in both groups will be followed up at specific times points until 180 days post inclusion. The vaccinated and control groups will be compared according to COVID-19 related outcomes. Main outcomes The primary outcomes are the incidence coefficient of infection by SARS-CoV-2 determined by RT-PCR of naso-oropharyngeal swab specimen or rapid lateral flow IgG and IgM test, and presence of general COVID-19 symptoms, disease severity and admission to hospital during the 180 days of follow up. The secondary outcome is the innate immune response elicited 15-20 days after vaccination. Randomisation The vaccine vial contains approximately 10 doses. In order to optimize the vaccine use, the randomisation was performed in blocks of 20 participants using the platform randomization.com [http://www.jerrydallal.com/random/permute.htm]. The randomization was prepared before any HW inclusion. The results were printed and inserted in sealed envelopes that were numbered with BCG-001 to BCG-400. The printed results as well the envelopes had the same numbers. At the time of the randomisation, each participant that meets the inclusion criteria will receive a consecutive participant number [BCG-001-BCG-400]. The sealed envelope with the assigned number, blinded to the researchers, will be opened in front of the participant and the arm allocation will be known. Blinding (masking) There is no masking for the participants or for the healthcare providers. The study will be blinded to the laboratory researchers and to those who will be evaluating the outcomes and performing the statistical analyses. In this case, only the participant identification number will be available. Numbers to be randomised (sample size) Four hundred heath workers will be randomised in two groups. Two hundred participants will be vaccinated, and 200 participants will not be vaccinated. Trial Status The protocol approved by the Brazilian Ethical Committee is the seventh version, number CAAE: 31783720.0.0000.5078. The trial has been recruiting since September 20th, 2020. The clinical trial protocol was registered on August 5th, 2020. It is estimated that recruitment will finish by March 2021. Trial registration The protocol number was registered on August 5th, 2020 at REBEC (Registro Brasileiro de Ensaios Clínicos). Register number: RBR-4kjqtg and WHO trial registration number UTN: U1111-1256-3892. Full protocol The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol.

Tuberculosis is an infectious disease that affects millions of people worldwide with an annual mortality rate of 1.3 million. The mechanisms contributing to the loss of balance of immune responses and progression to active tuberculosis disease are unknown. Although CD4+ and CD8+ T cells and the cytokines they produce are crucial for protection against tuberculosis they have different roles in tuberculosis immunology. The function of CD4+ T cells has been extensively studied; however, less is known about the phenotype and function of CD8+ T cells. This study evaluated the specific expression of IFN-γ, IL-17, IL-10, and TGF-β and ex vivo expression of perforin and granzyme-B by CD8+ T cells from active tuberculosis individuals compared with latent infected individuals and non-latent infected individuals. Tuberculosis responses were correlated with the baciloscopy score. We observed that the presence of IL-10 and TGF-β expression and down-expression of granzyme-B in CD8+ T cells correlated with increased sputum bacillary load in active tuberculosis individuals. These findings provide new insights into the role of CD8+ T cells in Mycobacterium tuberculosis disease.

Intravascular stent infection is a rare complication with a high morbidity and high mortality; bacteria from the hospital environment form biofilms and are often multidrug-resistant (MDR). Antimicrobial peptides (AMPs) have been considered as alternatives to bacterial infection treatment. We analyzed the formation of the bacterial biofilm on the vascular stents and also tested the inhibition of this biofilm by AMPs to be used as treatment or coating. Antimicrobial activity and antibiofilm were tested with wasp (Agelaia-MPI, Polybia-MPII, Polydim-I) and scorpion (Con10 and NDBP5.8) AMPs against Acinetobacter baumannii clinical strains. A. baumannii formed a biofilm on the vascular stent. Agelaia-MPI and Polybia-MPII inhibited biofilm formation with bacterial cell wall degradation. Coating biofilms with polyethylene glycol (PEG 400) and Agelaia-MPI reduced 90% of A. baumannii adhesion on stents. The wasp AMPs Agelaia-MPI and Polybia-MPII had better action against MDR A. baumannii adherence and biofilm formation on vascular stents, preventing its formation and treating mature biofilm when compared to the other tested peptides.

Mycobacterium massiliense is a rapid growing, multidrug-resistant, non-tuberculous mycobacteria that is responsible for a wide spectrum of skin and soft tissue infections, as well as other organs, such as the lungs. Antimicrobial peptides had been described as broad-spectrum antimicrobial, chemotactic, and immunomodulator molecules. In this study we evaluated an antimicrobial peptide derived from scorpion Tityus obscurus as an anti-mycobacterial agent in vitro and in vivo. Bioinformatics analyses demonstrated that the peptide ToAP2 have a conserved region similar to several membrane proteins, as well as mouse cathelicidin. ToAP2 inhibited the growth of four M. massiliense strains (GO01, GO06, GO08, and CRM0020) at a minimal bactericidal concentration (MBC) of 200 µM. MBC concentration used to treat infected macrophages was able to inhibit 50% of the bacterial growth of all strains. ToAP2 treatment of infected mice with bacilli reduced the bacterial load in the liver, lung, and spleen, similarly to clarithromycin levels (90%). ToAP2 alone recruited monocytes (F4/80low Gr1), neutrophils (F4/80− Gr1), and eosinophils (F4/80+ Gr1+). ToAP2, together with M. massiliense infection, was able to increase F4/80low and reduce the percentage of F4/80high macrophages when compared with infected and untreated mice. ToAP2 has in vitro anti-microbial activity that is improved in vivo due to chemotactic activity.

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