Vaccine protection against the SARS-CoV-2 Omicron variant in macaques.

The rapid spread of the SARS-CoV-2 Omicron (B.1.1.529) variant, including in highly vaccinated populations, has raised important questions about the efficacy of current vaccines. In this study, we show that the mRNA-based BNT162b2 vaccine and the adenovirus-vector-based Ad26.COV2.S vaccine provide robust protection against high-dose challenge with the SARS-CoV-2 Omicron variant in cynomolgus macaques. We vaccinated 30 macaques with homologous and heterologous prime-boost regimens with BNT162b2 and Ad26.COV2.S. Following Omicron challenge, vaccinated macaques demonstrated rapid control of virus in bronchoalveolar lavage, and most vaccinated animals also controlled virus in nasal swabs. However, 4 vaccinated animals that had moderate Omicron-neutralizing antibody titers and undetectable Omicron CD8+ T cell responses failed to control virus in the upper respiratory tract. Moreover, virologic control correlated with both antibody and T cell responses. These data suggest that both humoral and cellular immune responses contribute to vaccine protection against a highly mutated SARS-CoV-2 variant.

Autism-related dietary preferences mediate autism-gut microbiome associations.

There is increasing interest in the potential contribution of the gut microbiome to autism spectrum disorder (ASD). However, previous studies have been underpowered and have not been designed to address potential confounding factors in a comprehensive way. We performed a large autism stool metagenomics study (n = 247) based on participants from the Australian Autism Biobank and the Queensland Twin Adolescent Brain project. We found negligible direct associations between ASD diagnosis and the gut microbiome. Instead, our data support a model whereby ASD-related restricted interests are associated with less-diverse diet, and in turn reduced microbial taxonomic diversity and looser stool consistency. In contrast to ASD diagnosis, our dataset was well powered to detect microbiome associations with traits such as age, dietary intake, and stool consistency. Overall, microbiome differences in ASD may reflect dietary preferences that relate to diagnostic features, and we caution against claims that the microbiome has a driving role in ASD.

A Human IgSF Cell-Surface Interactome Reveals a Complex Network of Protein-Protein Interactions.

Cell-surface protein-protein interactions (PPIs) mediate cell-cell communication, recognition, and responses. We executed an interactome screen of 564 human cell-surface and secreted proteins, most of which are immunoglobulin superfamily (IgSF) proteins, using a high-throughput, automated ELISA-based screening platform employing a pooled-protein strategy to test all 318,096 PPI combinations. Screen results, augmented by phylogenetic homology analysis, revealed ∼380 previously unreported PPIs. We validated a subset using surface plasmon resonance and cell binding assays. Observed PPIs reveal a large and complex network of interactions both within and across biological systems. We identified new PPIs for receptors with well-characterized ligands and binding partners for "orphan" receptors. New PPIs include proteins expressed on multiple cell types and involved in diverse processes including immune and nervous system development and function, differentiation/proliferation, metabolism, vascularization, and reproduction. These PPIs provide a resource for further biological investigation into their functional relevance and may offer new therapeutic drug targets.

Mucosal boosting enhances vaccine protection against SARS-CoV-2 in macaques.

A limitation of current SARS-CoV-2 vaccines is that they provide minimal protection against infection with current Omicron subvariants1,2, although they still provide protection against severe disease. Enhanced mucosal immunity may be required to block infection and onward transmission. Intranasal administration of current vaccines has proven inconsistent3-7, suggesting that alternative immunization strategies may be required. Here we show that intratracheal boosting with a bivalent Ad26-based SARS-CoV-2 vaccine results in substantial induction of mucosal humoral and cellular immunity and near-complete protection against SARS-CoV-2 BQ.1.1 challenge. A total of 40 previously immunized rhesus macaques were boosted with a bivalent Ad26 vaccine by the intramuscular, intranasal and intratracheal routes, or with a bivalent mRNA vaccine by the intranasal route. Ad26 boosting by the intratracheal route led to a substantial expansion of mucosal neutralizing antibodies, IgG and IgA binding antibodies, and CD8+ and CD4+ T cell responses, which exceeded those induced by Ad26 boosting by the intramuscular and intranasal routes. Intratracheal Ad26 boosting also led to robust upregulation of cytokine, natural killer, and T and B cell pathways in the lungs. After challenge with a high dose of SARS-CoV-2 BQ.1.1, intratracheal Ad26 boosting provided near-complete protection, whereas the other boosting strategies proved less effective. Protective efficacy correlated best with mucosal humoral and cellular immune responses. These data demonstrate that these immunization strategies induce robust mucosal immunity, suggesting the feasibility of developing vaccines that block respiratory viral infections.

Isoform-specific functions of PPARγ in gene regulation and metabolism.

Peroxisome proliferator-activated receptor γ (PPARγ) is a nuclear receptor that is a vital regulator of adipogenesis, insulin sensitivity, and lipid metabolism. Activation of PPARγ by antidiabetic thiazolidinediones (TZD) reverses insulin resistance but also leads to weight gain that limits the use of these drugs. There are two main PPARγ isoforms, but the specific functions of each are not established. Here we generated mouse lines in which endogenous PPARγ1 and PPARγ2 were epitope-tagged to interrogate isoform-specific genomic binding, and mice deficient in either PPARγ1 or PPARγ2 to assess isoform-specific gene regulation. Strikingly, although PPARγ1 and PPARγ2 contain identical DNA binding domains, we uncovered isoform-specific genomic binding sites in addition to shared sites. Moreover, PPARγ1 and PPARγ2 regulated a different set of genes in adipose tissue depots, suggesting distinct roles in adipocyte biology. Indeed, mice with selective deficiency of PPARγ1 maintained body temperature better than wild-type or PPARγ2-deficient mice. Most remarkably, although TZD treatment improved glucose tolerance in mice lacking either PPARγ1 or PPARγ2, the PPARγ1-deficient mice were protected from TZD-induced body weight gain compared with PPARγ2-deficient mice. Thus, PPARγ isoforms have specific and separable metabolic functions that may be targeted to improve therapy for insulin resistance and diabetes.

A pan-influenza antibody inhibiting neuraminidase via receptor mimicry.

Rapidly evolving influenza A viruses (IAVs) and influenza B viruses (IBVs) are major causes of recurrent lower respiratory tract infections. Current influenza vaccines elicit antibodies predominantly to the highly variable head region of haemagglutinin and their effectiveness is limited by viral drift1 and suboptimal immune responses2. Here we describe a neuraminidase-targeting monoclonal antibody, FNI9, that potently inhibits the enzymatic activity of all group 1 and group 2 IAVs, as well as Victoria/2/87-like, Yamagata/16/88-like and ancestral IBVs. FNI9 broadly neutralizes seasonal IAVs and IBVs, including the immune-evading H3N2 strains bearing an N-glycan at position 245, and shows synergistic activity when combined with anti-haemagglutinin stem-directed antibodies. Structural analysis reveals that D107 in the FNI9 heavy chain complementarity-determinant region 3 mimics the interaction of the sialic acid carboxyl group with the three highly conserved arginine residues (R118, R292 and R371) of the neuraminidase catalytic site. FNI9 demonstrates potent prophylactic activity against lethal IAV and IBV infections in mice. The unprecedented breadth and potency of the FNI9 monoclonal antibody supports its development for the prevention of influenza illness by seasonal and pandemic viruses.

The Dysregulated IL-23/TH17 Axis in Endometriosis Pathophysiology.

Endometriosis is a chronic inflammatory disease in which endometrial-like tissue grows ectopically, resulting in pelvic pain and infertility. IL-23 is a key contributor in the development and differentiation of TH17 cells, driving TH17 cells toward a pathogenic profile. In a variety of inflammatory and autoimmune disorders, TH17 cells secrete proinflammatory cytokines, including IL-17, contributing to disease pathophysiology. Our studies and others have implicated IL-17 and TH17 cell dysregulation in endometriosis, which is associated with disease severity. In this article, we address whether IL-23-driven TH17 cells contribute to cardinal features of lesion proliferation, vascularization, and inflammation in endometriosis using patient samples, representative cell lines, and our established mouse model of endometriosis. The results indicated dysregulated expression of key genes in the IL-23/TH17 axis in patient ectopic and eutopic endometrial samples and increased IL-23 protein in patient plasma compared with controls. In vitro studies using primary human TH cells determined that rIL-23 mixture treatment increased pathogenic TH17 cell frequency. Similarly, rIL-23 treatment of cell lines (12Z cells, EECCs, HUVECs, and hESCs) representative of the endometriotic lesion microenvironment increased cytokines and growth factors, which play a role in lesion establishment and maintenance. In a syngeneic mouse model of endometriosis, rIL-23 treatment altered numbers of myeloid and T cell subsets in peritoneal fluid and increased giant cells within the lesion. Lesions from rIL-23-treated mice did not reveal significant alterations in proliferation/vascularization, although trends of increased proliferation and vascularization were observed. Collectively, these findings provide insights into the impact of the IL-23/TH17 axis on local immune dysfunction and broadly on endometriosis pathophysiology.

Prediction of acute myeloid leukaemia risk in healthy individuals.

The incidence of acute myeloid leukaemia (AML) increases with age and mortality exceeds 90% when diagnosed after age 65. Most cases arise without any detectable early symptoms and patients usually present with the acute complications of bone marrow failure1. The onset of such de novo AML cases is typically preceded by the accumulation of somatic mutations in preleukaemic haematopoietic stem and progenitor cells (HSPCs) that undergo clonal expansion2,3. However, recurrent AML mutations also accumulate in HSPCs during ageing of healthy individuals who do not develop AML, a phenomenon referred to as age-related clonal haematopoiesis (ARCH)4-8. Here we use deep sequencing to analyse genes that are recurrently mutated in AML to distinguish between individuals who have a high risk of developing AML and those with benign ARCH. We analysed peripheral blood cells from 95 individuals that were obtained on average 6.3 years before AML diagnosis (pre-AML group), together with 414 unselected age- and gender-matched individuals (control group). Pre-AML cases were distinct from controls and had more mutations per sample, higher variant allele frequencies, indicating greater clonal expansion, and showed enrichment of mutations in specific genes. Genetic parameters were used to derive a model that accurately predicted AML-free survival; this model was validated in an independent cohort of 29 pre-AML cases and 262 controls. Because AML is rare, we also developed an AML predictive model using a large electronic health record database that identified individuals at greater risk. Collectively our findings provide proof-of-concept that it is possible to discriminate ARCH from pre-AML many years before malignant transformation. This could in future enable earlier detection and monitoring, and may help to inform intervention.

Neurocognitive effects a combined polyphenolic-rich herbal extract in healthy middle-aged adults - a randomised, double-blind, placebo-controlled study.

Objective: This study assessed whether polyphenolic rich supplement containing Bacopa monnieri (BM: 300 mg), Panax quinquefolius ginseng (PQ: 100 mg) and whole coffee fruit extract (WCFE: 100 mg) could enhance cognitive performance, affect and cerebral-cortical activation over 28-days of intervention.Method: A randomised, double-blind, placebo-controlled, between-group study of 52 healthy adults between 35 and 65 years (M = 50.20, SD = 9.37) was conducted. Measures of cognition, affect and brain activity were measured at three time points: baseline, 28 days post intervention and 14 days post washout. At each time point, haemodynamic response in the prefrontal cortex (PFC) was measured using functional near-infrared spectroscopy (fNIRS), and serum brain-derived neurotrophic factor (BDNF).Results: The polyphenolic-rich supplement reliably improved positive affect and delayed recall compared to placebo following 28 days of supplementation. For the brain, those in the active condition showed greater PFC activation on performance of the 2-back tasks post supplementation compared to placebo (p < .05, d = 0.6).Discussion: This is the first report of a 28-day supplement intervention and 2-week follow-up study to assess changes in affect, cognition, cerebral haemodynamic response and BDNF in healthy middle-aged adults. The potential synergistic effects of polyphenolic compounds on neurocognitive function in middle-aged adults through emotional-cognitive processing and cognitive reserve are important for promoting brain and cognitive health.

Self-management intervention for patients following hospitalization for acute exacerbation of chronic obstructive pulmonary disease (AECOPD): A pilot randomized controlled trial.

The purpose of this study was to evaluate the handoff guidance (HG) self-management intervention for multimorbid chronic obstructive pulmonary disease (COPD) patients following hospitalization for acute exacerbation of COPD (AECOPD) using HG self-management intervention compared to a control group on COPD self-management outcomes (self-care, self-efficacy, health engagement) and assess feasibility, acceptability, and healthcare utilization. A randomized pilot study used a 2-group with repeated measures design. Adults with COPD who had been hospitalized for AECOPD were recruited. After discharge, the HG self-management intervention employed health coaching delivered at: 1-3, 10-12, and 20-22 days after hospital discharge. Follow-up data collected was collected at 1-3, 10-12, 20-22, 30, 60, and 90 days after hospital discharge. A total of 29 subjects participated, with a mean age of 66 (+8.7) years old, the majority were females (n = 18). Intervention participants reported the acceptability of the HG self-management intervention. Participants in both groups continued to report COPD symptoms after discharge, which decreased over time, although not significantly different by group. The use of COPD maintenance, monitoring, and management behaviors was higher in the treatment group, although not significantly different.

Case series of cefiderocol for salvage therapy in carbapenem-resistant Gram-negative infections.

PURPOSE: This case series describes real-world utilization of cefiderocol and associated clinical outcomes in the setting of carbapenem-resistant Gram-negative bacterial infections. METHODS: Adult hospitalized patients administered at least 5 days of cefiderocol as definitive treatment from October 1, 2020 to September 16, 2021 were included in this retrospective cohort analysis. The primary outcome was clinical success defined as a composite of 30 day survival, resolution of infection, and absence of 30 day recurrence of the same organism. RESULTS: Among 24 patients, pneumonia (19, 79%) was the most common source of infection with Acinetobacter baumannii (14, 58%) and P. aeruginosa (10, 42%) as the predominant organisms isolated. Cefiderocol monotherapy was used as definitive treatment in 16 (67%) patients. Eleven patients (46%) met clinical success. Thirty-day mortality occurred in ten (42%) patients while seven (29%) patients had recurrence of infection. Thirteen out of 21 total isolates (62%) tested for susceptibility were deemed susceptible. Of the 16 patients with available susceptibility, 9 (56%) had an infection where all isolated organisms were susceptible to cefiderocol. CONCLUSIONS: Our results provide additional insight into the in vivo activity of cefiderocol. Cefiderocol remains a salvage option for carbapenem-resistant Gram-negative organisms.

Evaluation of hemolysis, lipemia, and icterus interference with common clinical immunoassays.

OBJECTIVES: Hemolysis, icterus, and lipemia (HIL) are common sources of endogenous interference in clinical laboratory testing. Defining the threshold of interference for immunoassays enables appropriate reporting of their results when they are affected by HIL. METHODS: Pools of residual patient serum samples were spiked with a known amount of interferent to create samples with varying concentrations of hemolysate, bilirubin, and Intralipid that mimicked the effects of endogenous HIL. Samples were analysed on the Alinity i analyser (Abbott Diagnostics) for more than 25 immunoassays. The average recovery relative to the non-spiked sample was calculated for each interference level and was compared to a predefined allowable bias. RESULTS: C-peptide, estradiol, serum folate, free T4, homocysteine, insulin, and vitamin B12 were found to be affected by hemolysis, at hemoglobin concentrations between 0.3 to 20 g/L. Immunoassays for BNP, estradiol, free T3, and homocysteine were affected by icterus at conjugated bilirubin concentrations between 50 to 1,044 µmol/L. BNP, serum folate, and homocysteine were affected by Intralipid with measured triglyceride concentrations between 0.8 to 10 mmol/L. Lastly, serological immunoassays for HIV and hepatitis A, B and C were also affected by interferences. CONCLUSIONS: Immunoassays are impacted by varying degrees of HIL interference. Some measurands, in the presence of interference, are affected in a manner not previously indicated. The data presented herein provide an independent evaluation of HIL thresholds and will be of aid to resource-limited clinical laboratories that are unable to internally verify endogenous interferences when implementing the Alinity i analyser.

Antimicrobial prescribing after rapid influenza PCR implementation in the emergency department.

INTRO: Influenza shares common symptoms with bacterial pneumonia, which may result in unnecessary antibiotic prescriptions in the emergency department (ED) when the diagnosis is unknown. Rapid influenza polymerase chain reaction (PCR) tests have reduced turnaround times compared to standard multiplex PCR respiratory panels allowing for earlier diagnosis, which may improve antimicrobial stewardship outcomes in the ED. This study aims to compare antibiotic and antiviral use before and after deployment of the rapid influenza PCR in the ED. METHODS: This single-center, retrospective, cohort study included pediatric and adult patients discharged from the ED with a positive influenza test using a standard multiplex PCR respiratory panel (January 2017 - July 2019) or rapid PCR (July 2019 - February 2020). The primary endpoint was number of antibiotic prescriptions pre- and post-implementation of the rapid influenza PCR in the ED. Secondary endpoints included number of antiviral prescriptions, duration of antimicrobial therapy, test turnaround time, ED length of stay, 30-day readmission, and adverse events. A multivariable logistic regression evaluated patient factors associated with antimicrobial prescribing. RESULTS: A total of 620 positive influenza results were identified with 280 patients (standard multiplex PCR = 33; rapid PCR = 247) meeting inclusion criteria. Patients were less likely to be prescribed antibiotics (39.4% vs 8.9%, OR 0.15, 95% CI 0.067-0.34) and more likely to be prescribed antivirals (24.2% vs 61.1%, OR 4.92, 95% CI 2.13-11.34) with the rapid influenza PCR. Rapid influenza PCR significantly reduced ED length of stay (4.9 vs 3.4 h, p < 0.01) and test turnaround time (27 h vs 3.5 h, p < 0.01). Patients at high risk for complications associated with influenza were more likely to be prescribed antiviral therapy (22.7% vs 67.8%, OR 7.16, 95% CI 2.52-20.40). Based on the regression analysis conducted, asthma, (OR 3.5, 95% CI 1.48-8.26), immunosuppression (OR 9.6, 95% CI 1.18-78.2), and age <5 years old (OR 3.1, 95% CI 1.80-5.45) were predictors of antiviral prescribing. CONCLUSION: Implementation of a rapid influenza PCR in the ED reduced antibiotic use and optimized antiviral therapy for patients with influenza including those at higher risk of complications.

Understanding amphidromy in Hawai'i: 'O'opu nakea (Awaous stamineus).

Hawai'i is home to 'o'opu nakea (Awaous stamineus), a culturally significant, endemic, goby that exhibits an amphidromous life cycle characterized by a marine larval stage followed by post-larval recruitment to streams, where they live to become reproductive adults. However, it was recently suggested that their migration to the ocean might not be obligatory, as originally thought. Despite their importance in Hawaiian traditions and the ecology of Hawaiian freshwater ecosystems, we still lack a full understanding of their migratory patterns and life history due to the difficulties in determining the environmental migratory cues that set the timing and location of their migratory paths. This study examined environmental factors, such as mean annual rainfall, streamflow, and water chemistry, to determine if they play a role in whether A. stamineus spend their larval period in the ocean or their entire life cycle in freshwater streams. We sampled A. stamineus (n = 90) from three streams (Kahana, Kahalu'u, and Waimanalo) on the island of O'ahu, Hawai'i that represented the range of hydroclimatic gradient in wet-habitat conditions on the windward side of the island and characterized their migratory pattern using elemental analysis of sagittae, the largest pair of otoliths (calcareous ear structures). Based on otolith strontium:calcium and barium:calcium ratios, we determined if individuals spent their larval period in the ocean or the stream. We found that 100% of individuals displayed clear evidence of marine residence during their larval phase, regardless of the environmental factors the fish experienced. This study highlights the necessity of stream-ocean connectivity for the survival of A. stamineus and emphasizes the importance of stream-mouth conservation and management as it is a critical transition zone in stream-ocean-stream migratory pathways.

Genetic evidence for an inhibitory role of tomosyn in insulin-stimulated GLUT4 exocytosis.

Exocytosis is a vesicle fusion process driven by soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs). A classic exocytic pathway is insulin-stimulated translocation of the glucose transporter type 4 (GLUT4) from intracellular vesicles to the plasma membrane in adipocytes and skeletal muscles. The GLUT4 exocytic pathway plays a central role in maintaining blood glucose homeostasis and is compromised in insulin resistance and type 2 diabetes. A candidate regulator of GLUT4 exocytosis is tomosyn, a soluble protein expressed in adipocytes. Tomosyn directly binds to GLUT4 exocytic SNAREs in vitro but its role in GLUT4 exocytosis was unknown. In this work, we used CRISPR-Cas9 genome editing to delete the two tomosyn-encoding genes in adipocytes. We observed that both basal and insulin-stimulated GLUT4 exocytosis was markedly elevated in the double knockout (DKO) cells. By contrast, adipocyte differentiation and insulin signaling remained intact in the DKO adipocytes. In a reconstituted liposome fusion assay, tomosyn inhibited all the SNARE complexes underlying GLUT4 exocytosis. The inhibitory activity of tomosyn was relieved by NSF and α-SNAP, which act in concert to remove tomosyn from GLUT4 exocytic SNAREs. Together, these studies revealed an inhibitory role for tomosyn in insulin-stimulated GLUT4 exocytosis in adipocytes. We suggest that tomosyn-arrested SNAREs represent a reservoir of fusion capacity that could be harnessed to treat patients with insulin resistance and type 2 diabetes.

A role for bioinorganic chemistry in the reactivation of mutant p53 in cancer.

Metal ion dysregulation has been implicated in a number of diseases from neurodegeneration to cancer. While defective metal ion transport mechanisms are known to cause specific diseases of genetic origin, the role of metal dysregulation in many diseases has yet to be elucidated due to the complicated function (both good and bad!) of metal ions in the body. A breakdown in metal ion speciation can manifest in several ways from increased reactive oxygen species (ROS) generation to an increase in protein misfolding and aggregation. In this review, we will discuss the role of Zn in the proper function of the p53 protein in cancer. The p53 protein plays a critical role in the prevention of genome mutations via initiation of apoptosis, DNA repair, cell cycle arrest, anti-angiogenesis, and senescence pathways to avoid propagation of damaged cells. p53 is the most frequently mutated protein in cancer and almost all cancers exhibit malfunction along the p53 pathway. Thus, there has been considerable effort dedicated to restoring normal p53 expression and activity to mutant p53. This includes understanding the relative populations of the Zn-bound and Zn-free p53 in wild-type and mutant forms, and the development of metallochaperones to re-populate the Zn binding site to restore mutant p53 activity. Parallels will be made to the development of multifunctional metal binding agents for modulating the aggregation of the amyloid-beta peptide in Alzheimer's Disease (AD).

Posttraumatic stress disorder and complex posttraumatic stress disorder in UK police officers.

BACKGROUND: We investigated work-related exposure to stressful and traumatic events in police officers, including repeated exposure to traumatic materials, and predicted that ICD-11 complex PTSD (CPTSD) would be more prevalent than posttraumatic stress disorder (PTSD). The effects of demographic variables on exposure and PTSD were examined, along with whether specific types of exposure were uniquely associated with PTSD or CPTSD. METHODS: An online survey covering issues about trauma management, wellbeing and working conditions was disseminated via social media and official policing channels throughout the UK. In total, 10 401 serving police officers self-identified as having been exposed to traumatic events. Measurement of PTSD and CPTSD utilised the International Trauma Questionnaire. RESULTS: The prevalence of PTSD was 8.0% and of CPTSD was 12.6%. All exposures were associated with PTSD and CPTSD in bivariate analyses. Logistic regression indicated that both disorders were more common in male officers, and were associated independently with frequent exposure to traumatic incidents and traumatic visual material, and with exposure to humiliating behaviours and sexual harassment, but not to verbal abuse, threats or physical violence. Compared to PTSD, CPTSD was associated with exposure to humiliating behaviours and sexual harassment, and also with lower rank and more years of service. CONCLUSIONS: CPTSD was more common than PTSD in police officers, and the data supported a cumulative burden model of CPTSD. The inclusion in DSM-5 Criterion A of work-related exposure to traumatic materials was validated for the first time. Levels of PTSD and CPTSD mandate enhanced occupational mental health services.

Changes in antibiotic prescribing following COVID-19 restrictions: Lessons for post-pandemic antibiotic stewardship.

AIMS: Public health responses to reduce SARS-CoV-2 transmission have profoundly affected the epidemiology and management of other infections. We examined the impact of COVID-19 restrictions on antibiotic dispensing in Australia. METHODS: We used national claims data to investigate antibiotic dispensing trends from November 2015 to October 2020 and whether changes reflected reductions in primary care consultations. We used interrupted time series analysis to quantify changes in monthly antibiotic dispensing and face-to-face and telehealth GP consultations and examined changes by recipient age, pharmacy State and prescriber specialty. RESULTS: Over the study period, an estimated 19 921 370 people had 125 495 137 antibiotic dispensings, 71% prescribed by GPs. Following COVID-19 restrictions, we observed a sustained 36% (95% CI: 33-40%) reduction in antibiotic dispensings from April 2020. Antibiotics recommended for managing respiratory tract infections showed large reductions (range 51-69%), whereas those recommended for non-respiratory infections were unchanged. Dispensings prescribed by GPs decreased from 63.5 per 1000 population for April-October 2019 to 37.0 per 1000 for April-October 2020. Total GP consultation rates remained stable, but from April 2020, 31% of consultations were telehealth. CONCLUSION: In a setting with a low COVID-19 incidence, restrictions were associated with a substantial reduction in community dispensings of antibiotics primarily used to treat respiratory infections, coincident with reported reductions in respiratory viral infections. Our findings are informative for post-pandemic antimicrobial stewardship and highlight the potential to reduce inappropriate prescribing by GPs and specialists for respiratory viral infections.