How many sites should an orthopedic trauma prospective multicenter trial have? A marginal analysis of the Major Extremity Trauma Research Consortium completed trials.

BACKGROUND: Multicenter trials in orthopedic trauma are costly, yet crucial to advance the science behind clinical care. The number of sites is a key cost determinant. Each site has a fixed overhead cost, so more sites cost more to the study. However, more sites can reduce total costs by shortening the study duration. We propose to determine the optimal number of sites based on known costs and predictable site enrollment. METHODS: This retrospective marginal analysis utilized administrative and financial data from 12 trials completed by the Major Extremity Trauma Research Consortium. The studies varied in size, design, and clinical focus. Enrollment across the studies ranged from 1054 to 33 patients. Design ranged from an observational study with light data collection to a placebo-controlled, double-blinded, randomized controlled trial. Initial modeling identified the optimal number of sites for each study and sensitivity analyses determined the sensitivity of the model to variation in fixed overhead costs. RESULTS: No study was optimized in terms of the number of participating sites. Excess sites ranged from 2 to 39. Excess costs associated with extra sites ranged from $17K to $330K with a median excess cost of $96K. Excess costs were, on average, 7% of the total study budget. Sensitivity analyses demonstrated that studies with higher overhead costs require more sites to complete the study as quickly as possible. CONCLUSIONS: Our data support that this model may be used by clinical researchers to achieve future study goals in a more cost-effective manner. TRIAL REGISTRATION: Please see Table 1 for individual trial registration numbers and dates of registration.

The VANCO Trial Findings Are Generalizable to a North American Trauma Registry.

OBJECTIVES: To estimate the generalizability of treatment effects observed in the VANCO trial to a broader population of patients with tibial plateau or pilon fractures. METHODS: Design and Setting: Clinical trial data from 36 United States trauma centers and Trauma Quality Programs registry data from more than 875 Level I-III trauma centers in the United States and Canada.Patient Selection Criteria: Patients enrolled in the VANCO trial treated with intrawound vancomycin powder from January 2015 to June 2017 and 31,924 VANCO-eligible TQP patients admitted in 2019 with tibial plateau and pilon fractures.Outcome Measure and Comparisons: Deep surgical site infection and gram-positive deep surgical site infection estimated in the TQP sample weighed by the inverse probability of trial participation. RESULTS: The 980 patients in the VANCO trial were highly representative of 31,924 TQP VANCO-eligible patients (Tipton generalizability index 0.96). It was estimated that intrawound vancomycin powder reduced the odds of deep surgical infection by odds ratio (OR) = 0.46 (95% confidence interval [CI] 0.25-0.86) and gram-positive deep surgical infection by OR = 0.39 (95% CI, 0.18-0.84) within the TQP sample of VANCO-eligible patients. For reference, the trial average treatment effects for deep surgical infection and gram-positive deep surgical infection were OR = 0.60 (95% CI, 0.37-0.98) and OR = 0.44 (95% CI, 0.23-0.80), respectively. CONCLUSIONS: This generalizability analysis found that the inferences of the VANCO trial generalize and might even underestimate the effects of intrawound vancomycin powder when observed in a wider population of patients with tibial plateau and pilon fractures. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Predictors of participation in online self-management programs: A longitudinal observational study.

PURPOSE/OBJECTIVE: Lack of patient participation and engagement remains a barrier to implementing effective online self-management and behavioral health interventions. Identifying patient characteristics associated with engagement rates may lead to interventions that improve engagement in traditional and online self-management programs. In this study, two online self-management and recovery programs were evaluated to identify factors that predict patient engagement. RESEARCH METHOD/DESIGN: Predictors were collected in a questionnaire at baseline before 435 participants started either of the two interventions. One or two online lessons were completed per week with seven or eight total lessons to complete in each program, and each lesson took about 20-30 min to finish. Full patient engagement was defined as completing all lessons and assessments in the program and partial engagement as attempting at least one lesson or assessment. RESULTS: Predictors of full patient engagement were self-rated confidence in completing the program or being over 60 years of age. Predictors of at least partial patient engagement were experienced ordering online or being over 50 years of age. CONCLUSIONS/IMPLICATIONS: Identifying profiles of individuals who predict poor engagement may improve implementation and the health outcomes of intervention programs. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Development of A Standardized Opsonophagocytosis Killing Assay for Group B Streptococcus and Assessment in an Interlaboratory Study.

The placental transfer of antibodies that mediate bacterial clearance via phagocytes is likely important for protection against invasive group B Streptococcus (GBS) disease. A robust functional assay is essential to determine the immune correlates of protection and assist vaccine development. Using standard reagents, we developed and optimized an opsonophagocytic killing assay (OPKA) where dilutions of test sera were incubated with bacteria, baby rabbit complement (BRC) and differentiated HL60 cells (dHL60) for 30 min. Following overnight incubation, the surviving bacteria were enumerated and the % bacterial survival was calculated relative to serum-negative controls. A reciprocal 50% killing titer was then assigned. The minimal concentrations of anti-capsular polysaccharide (CPS) IgG required for 50% killing were 1.65-3.70 ng/mL (depending on serotype). Inhibition of killing was observed using sera absorbed with homologous CPS but not heterologous CPS, indicating specificity for anti-CPS IgG. The assay performance was examined in an interlaboratory study using residual sera from CPS-conjugate vaccine trials with international partners in the Group B Streptococcus Assay STandardisatiON (GASTON) Consortium. Strong correlations of reported titers between laboratories were observed: ST-Ia r = 0.88, ST-Ib r = 0.91, ST-II r = 0.91, ST-III r = 0.90 and ST-V r = 0.94. The OPKA is an easily transferable assay with accessible standard reagents and will be a valuable tool to assess GBS-specific antibodies in natural immunity and vaccine studies.

The Rates of Postmastectomy Immediate Breast Reconstruction during the Initial Months of the COVID-19 Pandemic.

Background: Coronavirus disease 2019 (COVID-19) pandemic-related changes may have led to changes in immediate breast reconstruction (IBR) rates. We aimed to evaluate these changes before, during, and after the initial wave of COVID-19. Methods: We retrospectively reviewed women who underwent mastectomy with or without IBR from January 1 to September 30, 2019 and from January 1 to September 30, 2020, and compared demographic, clinical, and surgical variables between defined time periods. Results: A total of 202 mastectomies were included. Fewer patients underwent IBR during the initial surge of COVID-19 (surge period) compared with the months before (presurge period; 38.46% versus 70.97%, P = 0.0433). When comparing the postsurge period with a year before (postsurge control), fewer patients underwent reconstruction even after the initial surge had passed (53.13% versus 81.25%, P = 0.0007). Those who underwent IBR were older than the year before (59.34 versus 53.06, P = 0.0181). The median number of postoperative visits in the postsurge period was 8.50 (interquartile range: 6-12) compared with 14 (interquartile range: 8-20.50) in the year before (P = 0.0017). The overall incidences of complications and unanticipated resource utilization were also significantly lower in the postsurge period compared with the year before [5.88% versus 30.77% (P = 0.0055), and 14.71% versus 28.85% (P = 0.0103), respectively]. Conclusions: IBR rates were lower even after the initial surge than at the year before. Furthermore, during the pandemic, IBR patients were older, had fewer follow-up visits, and fewer reported complications.

Clinical outcomes of non-surgical root canal obturations using NeoMTA: A retrospective series of case reports.

NeoMTA is a commercially available tricalcium silicate-based cement intended for contact with pulp and periradicular tissues. The purpose of this study was to retrospectively evaluate the outcomes of non-surgical root canal treatments with NeoMTA obturations. Patients were treated in a private endodontic practice between 2015 and 2018. All cases, including initial treatments and retreatments, were either fully obturated with NeoMTA, or using gutta-percha with NeoMTA as an endodontic sealer. Outcomes were assessed using follow-up examination data with digital periapical radiographs with a minimum of a 1-year recall. Teeth were classified based on the clinical examination as: healed/healing (success), or non-healed (failure). 265 teeth were included with an average follow-up time of 1.3 years. The overall success rate was 91.7%. Only the presence of a pre-operative periapical radiolucency was found to significantly affect success. Comparison of obturation techniques demonstrated no effect on outcomes. NeoMTA is suitable for endodontic obturation.

Application of Bayesian Methods to Help Interpret the VANCO Trial Results.

OBJECTIVE: To determine whether a Bayesian analysis changes the results of the VANCO trial. DESIGN: A secondary analysis of a randomized clinical trial using Bayesian methods. SETTING: Thirty-six US trauma centers. PATIENTS: Patients ages 18-80 years with a tibial plateau or pilon fracture deemed high risk of infection and definitively treated with plate and screw fixation. INTERVENTION: Patients were randomly allocated to receive 1000 mg of intrawound vancomycin powder at their definitive fixation or to a control group that received no topical antibiotics. MAIN OUTCOME MEASUREMENTS: A deep surgical site infection requiring operative treatment within 6 months of definitive fixation. Secondary outcomes included gram-positive and gram-negative-only deep surgical site infections. RESULTS: Of the 980 patients randomized, 874 (89%) had at least 140 days of follow-up and were included in this Bayesian analysis. The estimated probability that intrawound vancomycin powder reduces the risk of a deep surgical site infection is >98% [relative risk (RR), 0.66; 95% credible interval (CrI), 0.46-0.98]. There is a >99% chance intrawound vancomycin powder reduces gram-positive infections and an 80% chance the magnitude of this risk reduction exceeds 35% (RR, 0.52; 95% CrI, 0.33-0.84) exists. It is unlikely (44%) that intrawound vancomycin powder prevents gram-negative surgical site infections (RR, 1.06; 95% CrI, 0.48-2.45). CONCLUSIONS: There is a high probability (>98%) that intrawound vancomycin powder reduces deep surgical site infections in patients with tibial plateau or pilon fractures at high risk of infection and even more likely it reduces deep infections with gram-positive pathogens (>99%). LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Delivery of Lung-protective Ventilation for Acute Respiratory Distress Syndrome: A Hybrid Implementation-Effectiveness Trial.

Rationale: Lung-protective ventilation (LPV) improves outcomes for patients with acute respiratory distress syndrome (ARDS), but adherence remains inadequate. Objectives: To measure the process and clinical impacts of implementation of a science-based intervention to improve LPV adherence for patients with ARDS, in part by increased use of clinical decision support (CDS). Methods: We conducted a type III hybrid implementation/effectiveness pilot trial enrolling adult patients with ARDS admitted to three hospitals before and after the launch of a multimodal implementation intervention to increase the use of mechanical ventilation CDS and improve LPV adherence. The primary outcome was patients' percentage of time adherent to low tidal volume (⩽6.5 ml/kg predicted body weight) ventilation (LTVV). Secondary outcomes included adherence to prescribed oxygenation settings, the use of the CDS tool's independent oxygenation and ventilation components, ventilator-free days, and mortality. Analyses employed multivariable regression to compare adjusted pre- versus postintervention outcomes after the exclusion of a postintervention wash-in period. A sensitivity analysis measured process outcomes' level and trend change postintervention using segmented regression. Results: The 446 included patients had a mean age of 60 years, and 43% were female. Demographic and clinical characteristics were similar pre- versus postintervention. The adjusted proportion of adherent time increased postintervention for LTVV (9.2%; 95% confidence interval [CI], 3.8-14.5%) and prescribed oxygenation settings (11.9%; 95% CI, 7.2-16.5%), as did the probability patients spent ⩾90% of ventilated time on LTVV (adjusted odds ratio [aOR] 2.58; 95% CI, 1.64-4.10) and use of ventilation CDS (aOR, 41.3%; 95% CI, 35.9-46.7%) and oxygenation CDS (aOR, 54.3%; 95% CI, 50.9-57.7%). Ventilator-free days (aOR, 1.15; 95% CI, 0.81-1.62) and 28-day mortality (aOR, 0.78; 95% CI, 0.50-1.20) did not change significantly after intervention. Segmented regression analysis supported a causal relationship between the intervention and improved CDS usage but suggested trends before intervention rather than the studied intervention could explain increased LPV adherence after the intervention. Conclusions: In this pilot trial, a multimodal implementation intervention was associated with increased use of ventilator management CDS for patients with ARDS but was not associated with differences in clinical outcomes and may not have independently caused the observed postintervention improvements in LPV adherence. Clinical trial registered with www.clinicaltrials.gov (NCT03984175).

Enhanced immunogenicity of Mycobacterium bovis BCG through CRISPRi mediated depletion of AftC.

Mycobacterium tuberculosis causes the disease tuberculosis and affects a third of the world's population. The recent COVID-19 pandemic exacerbated the situation with a projected 27% increase in tuberculosis related deaths. M. tuberculosis has an elaborate cell wall consisting of peptidoglycan, arabinogalactan and mycolic acids which shield the bacilli from the toxic bactericidal milieu within phagocytes. Amongst, the numerous glycosyltransferase enzymes involved in mycobacterial cell wall biosynthesis, arabinofuranosyltransferase C (aftC) is responsible for the branching of the arabinan domain in both arabinogalactan and lipoarabinomannan. Using Clustered Regularly Interspaced Short Palindromic Repeats interference (CRISPRi) we have generated aftC knockdowns in Mycobacterium bovis BCG and demonstrated the generation of a truncated, immunogenic lipoarabinomannan within its cell envelope. The aftC depleted BCG mutants were unable to form characteristic mycobacterial pellicular biofilms and elicit a potent immunostimulatory phenotype compared to wild type M. bovis BCG in a THP1 cell line. This study paves the way to further explore novel BCG mutants as promising vaccine boosters in preventing pulmonary tuberculosis.

Impact of narrowing perioperative antibiotic prophylaxis for left ventricular assist device implantation.

BACKGROUND: Although infections are a significant potential complication among patients undergoing left ventricular assist device (LVAD) implantation, standardized surgical infection prophylaxis (SIP) regimens are not well defined. At Montefiore Medical Center, a 4-drug SIP regimen containing fluconazole, ciprofloxacin, rifampin, and vancomycin was previously utilized. In January 2020, the antimicrobial stewardship program implemented a 2-drug SIP regimen of vancomycin and cefazolin to limit exposure to broad-spectrum antibiotics. This study evaluated LVAD-associated infection rates prior to and following the SIP revision. METHODS: A retrospective review of patients who underwent LVAD implantation from 1/2018 to 4/2021 was performed. Infections were classified using the International Society for Heart and Lung Transplantation definitions. Infection rates at 2 weeks, 30 days, and 90 days post-implantation in the 4-drug SIP regimen (1/2018-12/2019) and the 2-drug SIP regimen (1/2020 to 4/2021) were compared. RESULTS: A total of 71 patients were included. The number of patients with LVAD-associated infections (including surgical site infections) was not significantly different in either SIP group at 2 weeks (9% vs. 4%, p = .64), 30 days (9% vs. 11%, p = .99), or 90 days (19% vs. 14%, p = .75). There was no statistically significant difference in 30 or 90-day mortality. LVAD-associated gram-negative (7% vs. 7%; p > .99) and fungal (5% vs. 0%; p = .51) infections were uncommon. The most common organism isolated was Staphylococcus aureus, and the most common type of infection was pneumonia in both SIP groups. CONCLUSION: No significant difference in LVAD-associated infections or infection-related mortality was observed with de-escalation of perioperative antibiotics. Additional studies with larger sample sizes are needed to endorse the findings of this study.

An alert tool to promote lung protective ventilation for possible acute respiratory distress syndrome.

Objective: Computer-aided decision tools may speed recognition of acute respiratory distress syndrome (ARDS) and promote consistent, timely treatment using lung-protective ventilation (LPV). This study evaluated implementation and service (process) outcomes with deployment and use of a clinical decision support (CDS) synchronous alert tool associated with existing computerized ventilator protocols and targeted patients with possible ARDS not receiving LPV. Materials and Methods: We performed an explanatory mixed methods study from December 2019 to November 2020 to evaluate CDS alert implementation outcomes across 13 intensive care units (ICU) in an integrated healthcare system with >4000 mechanically ventilated patients annually. We utilized quantitative methods to measure service outcomes including CDS alert tool utilization, accuracy, and implementation effectiveness. Attitudes regarding the appropriateness and acceptability of the CDS tool were assessed via an electronic field survey of physicians and advanced practice providers. Results: Thirty-eight percent of study encounters had at least one episode of LPV nonadherence. Addition of LPV treatment detection logic prevented an estimated 1812 alert messages (41%) over use of disease detection logic alone. Forty-eight percent of alert recommendations were implemented within 2 h. Alert accuracy was estimated at 63% when compared to gold standard ARDS adjudication, with sensitivity of 85% and positive predictive value of 62%. Fifty-seven percent of survey respondents observed one or more benefits associated with the alert. Conclusion: Introduction of a CDS alert tool based upon ARDS risk factors and integrated with computerized ventilator protocol instructions increased visibility to gaps in LPV use and promoted increased adherence to LPV.

Generation of a Universal Human Complement Source by Large-Scale Depletion of IgG and IgM from Pooled Human Plasma.

Complement is a key component of functional immunological assays used to evaluate vaccine-mediated immunity to a range of bacterial and viral pathogens. However, standardization of these assays is complicated due to the availability of a human complement source that lacks existing antibodies acquired either through vaccination or natural circulation of the pathogen of interest. We have developed a method for depleting both IgG and IgM in 200 mL batches from pooled hirudin-derived human plasma by sequential affinity chromatography using a Protein G Sepharose column followed by POROS™ CaptureSelect™ IgM Affinity resin. The production of large IgG- and IgM-depleted batches of human plasma that retains total hemolytic and alternative pathway activities allows for improved assay standardization and comparison of immune responses in large clinical trials.

Effect of Vitamin D Supplementation on Outcomes in People With Early Psychosis: The DFEND Randomized Clinical Trial.

Importance: People with psychotic disorders have an increased risk of vitamin D deficiency, which is evident during first-episode psychosis (FEP) and associated with unfavorable mental and physical health outcomes. Objective: To examine whether vitamin D supplementation contributes to improved clinical outcomes in FEP. Design, Setting, and Participants: This multisite, double-blind, placebo-controlled, parallel-group randomized clinical trial from the UK examined adults 18 to 65 years of age within 3 years of a first presentation with a functional psychotic disorder who had no contraindication to vitamin D supplementation. A total of 2136 patients were assessed for eligibility, 835 were approached, 686 declined participation or were excluded, 149 were randomized, and 104 were followed up at 6 months. The study recruited participants from January 19, 2016, to June 14, 2019, with the final follow-up (after the last dose) completed on December 20, 2019. Interventions: Monthly augmentation with 120 000 IU of cholecalciferol or placebo. Main Outcomes and Measures: The primary outcome measure was total Positive and Negative Syndrome Scale (PANSS) score at 6 months. Secondary outcomes included total PANSS score at 3 months; PANSS positive, negative, and general psychopathology subscale scores at 3 and 6 months; Global Assessment of Function scores (for symptoms and disability); Calgary Depression Scale score, waist circumference, body mass index, and glycated hemoglobin, total cholesterol, C-reactive protein, and vitamin D concentrations at 6 months; and a planned sensitivity analysis in those with insufficient vitamin D levels at baseline. Results: A total of 149 participants (mean [SD] age, 28.1 (8.5) years; 89 [59.7%] male; 65 [43.6%] Black or of other minoritized racial and ethnic group; 84 [56.4%] White [British, Irish, or of other White ethnicity]) were randomized. No differences were observed in the intention-to-treat analysis in the primary outcome, total PANSS score at 6 months (mean difference, 3.57; 95% CI, -1.11 to 8.25; P = .13), or the secondary outcomes at 3 and 6 months (PANSS positive subscore: mean difference, -0.98; 95% CI, -2.23 to 0.27 at 3 months; mean difference, 0.68; 95% CI, -0.69 to 1.99 at 6 months; PANSS negative subscore: mean difference, 0.68; 95% CI, -1.39 to 2.76 at 3 months; mean difference, 1.56; 95% CI, -0.31 to 3.44 at 6 months; and general psychopathology subscore: mean difference, -2.09; 95% CI, -4.36 to 0.18 at 3 months; mean difference, 1.31; 95% CI, -1.42 to 4.05 at 6 months). There also were no significant differences in the Global Assessment of Function symptom score (mean difference, 0.02; 95% CI, -4.60 to 4.94); Global Assessment of Function disability score (mean difference, -0.01; 95% CI, -5.25 to 5.23), or Calgary Depression Scale score (mean difference, -0.39; 95% CI, -2.05 to 1.26) at 6 months. Vitamin D levels were very low in the study group, especially in Black participants and those who identified as another minoritized racial and ethnic group, 57 of 61 (93.4%) of whom had insufficient vitamin D. The treatment was safe and led to a significant increase in 25-hydroxyvitamin D concentrations. Conclusions and Relevance: In this randomized clinical trial, no association was found between vitamin D supplementation and mental health or metabolic outcomes at 6 months. Because so few patients with FEP were vitamin D replete, the results of this study suggest that this group would benefit from active consideration in future population health strategies. Trial Registration: isrctn.org Identifier: ISRCTN12424842.

Increased rates of respiratory disease in schizophrenia: A systematic review and meta-analysis including 619,214 individuals with schizophrenia and 52,159,551 controls.

INTRODUCTION: Despite respiratory disease being a major cause of excess mortality in people with schizophrenia, the prevalence of respiratory conditions in this population is poorly defined. A systematic review and meta-analysis were conducted to establish the prevalence and association of respiratory diseases in people with schizophrenia. MATERIAL AND METHODS: Major electronic databases were searched from inception to 27 April 2020 for articles reporting respiratory disease (asthma, chronic obstructive pulmonary disease [COPD], pneumonia, and tuberculosis) in people with schizophrenia and, where possible, a control group. A random-effects meta-analysis was conducted. The study was registered with PROSPERO (CRD42018115137). RESULTS: Of 1569 citations, 21 studies consisting of 619,214 individuals with schizophrenia and 52,159,551 controls were included in the meta-analysis. Compared to the general population, people with schizophrenia had significantly higher rates of COPD (odds ratio [OR]: 1.82, 95% CI: 1.28-2.57), asthma (OR: 1.70, 95% CI: 1.02-2.83), and pneumonia (OR: 2.62, 95% CI: 1.10-6.23). In people with schizophrenia, the prevalence of COPD was 7.7% (95% CI: 4.0-14.4), asthma 7.5% (95% CI: 4.9-11.3), pneumonia 10.3% (95% CI 5.4-18.6), and tuberculosis 0.3% (95% CI 0.1 -0.8). After adjusting for publication bias, the prevalence of COPD increased to 19.9% (95% CI: 9.6-36.7). DISCUSSION: All respiratory diseases examined were significantly more prevalent in people with schizophrenia compared with the general population. Future studies should focus on improving the prevention and management of respiratory disease in this group to reduce associated excess mortality.

Immunological and pathological outcomes of SARS-CoV-2 challenge following formalin-inactivated vaccine in ferrets and rhesus macaques.

There is an urgent requirement for safe and effective vaccines to prevent COVID-19. A concern for the development of new viral vaccines is the potential to induce vaccine-enhanced disease (VED). This was reported in several preclinical studies with both SARS-CoV-1 and MERS vaccines but has not been reported with SARS-CoV-2 vaccines. We have used ferrets and rhesus macaques challenged with SARS-CoV-2 to assess the potential for VED in animals vaccinated with formaldehyde-inactivated SARS-CoV-2 (FIV) formulated with Alhydrogel, compared to a negative control vaccine. We showed no evidence of enhanced disease in ferrets or rhesus macaques given FIV except for mild transient enhanced disease seen 7 days after infection in ferrets. This increased lung pathology was observed at day 7 but was resolved by day 15. We also demonstrate that formaldehyde treatment of SARS-CoV-2 reduces exposure of the spike receptor binding domain providing a mechanistic explanation for suboptimal immunity.

Post-severe Acute Respiratory Syndrome Coronavirus 2 Monoclonal Antibody Treatment Hospitalizations as a Sentinel for Emergence of Viral Variants in New York City.

We partnered with the US Department of Health and Human Services to treat high-risk, nonadmitted coronavirus disease 2019 (COVID-19) patients with bamlanivimab in the Bronx, New York per Emergency Use Authorization criteria. Increasing posttreatment hospitalizations were observed monthly between December 2020 and March 2021 in parallel to the emergence of severe acute respiratory syndrome coronavirus 2 variants in New York City.

A recombinant commensal bacteria elicits heterologous antigen-specific immune responses during pharyngeal carriage.

The human nasopharynx contains a stable microbial ecosystem of commensal and potentially pathogenic bacteria, which can elicit protective primary and secondary immune responses. Experimental intranasal infection of human adults with the commensal Neisseria lactamica produced safe, sustained pharyngeal colonization. This has potential utility as a vehicle for sustained release of antigen to the human mucosa, but commensals in general are thought to be immunologically tolerated. Here, we show that engineered N. lactamica, chromosomally transformed to express a heterologous vaccine antigen, safely induces systemic, antigen-specific immune responses during carriage in humans. When the N. lactamica expressing the meningococcal antigen Neisseria Adhesin A (NadA) was inoculated intranasally into human volunteers, all colonized participants carried the bacteria asymptomatically for at least 28 days, with most (86%) still carrying the bacteria at 90 days. Compared to an otherwise isogenic but phenotypically wild-type strain, colonization with NadA-expressing N. lactamica generated NadA-specific immunoglobulin G (IgG)- and IgA-secreting plasma cells within 14 days of colonization and NadA-specific IgG memory B cells within 28 days of colonization. NadA-specific IgG memory B cells were detected in peripheral blood of colonized participants for at least 90 days. Over the same period, there was seroconversion against NadA and generation of serum bactericidal antibody activity against a NadA-expressing meningococcus. The controlled infection was safe, and there was no transmission to adult bedroom sharers during the 90-day period. Genetically modified N. lactamica could therefore be used to generate beneficial immune responses to heterologous antigens during sustained pharyngeal carriage.

ChAdOx1 nCoV-19 protection against SARS-CoV-2 in rhesus macaque and ferret challenge models.

Vaccines against SARS-CoV-2 are urgently required, but early development of vaccines against SARS-CoV-1 resulted in enhanced disease after vaccination. Careful assessment of this phenomena is warranted for vaccine development against SARS CoV-2. Here we report detailed immune profiling after ChAdOx1 nCoV-19 (AZD1222) and subsequent high dose challenge in two animal models of SARS-CoV-2 mediated disease. We demonstrate in rhesus macaques the lung pathology caused by SARS-CoV-2 mediated pneumonia is reduced by prior vaccination with ChAdOx1 nCoV-19 which induced neutralising antibody responses after a single intramuscular administration. In a second animal model, ferrets, ChAdOx1 nCoV-19 reduced both virus shedding and lung pathology. Antibody titre were boosted by a second dose. Data from these challenge models on the absence of enhanced disease and the detailed immune profiling, support the continued clinical evaluation of ChAdOx1 nCoV-19.

Streptococcus salivarius Isolates of Varying Acid Tolerance Exhibit F1F0-ATPase Conservation.

Genes encoding the subunits of the membrane-bound F1F0-ATPase (responsible for exporting protons from the cytoplasm and contributing to acid tolerance) were sequenced for 24 non-mutans streptococci isolated from carious lesions. Isolates, mostly Streptococcus salivarius, displayed a continuum of acid tolerance thresholds ranging from pH 4.55 to 3.39, but amino acid alignments of F1F0-ATPase subunits revealed few non-synonymous substitutions and these were unrelated to acid tolerance. Thus, the F1F0-ATPase is highly-conserved among S. salivarius isolates despite varying acid tolerance thresholds, supporting the contention that acid tolerance is determined by the level of gene/protein expression rather than variation in molecular structure.