Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial.

Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome.

Pneumococcal serotypes and risk factors in adult community-acquired pneumonia 2018-20; a multicentre UK cohort study.

Background: Higher-valency pneumococcal vaccines are anticipated. We aimed to describe serotype distribution and risk factors for vaccine-serotype community-acquired pneumonia (CAP) in the two years pre-SARS-CoV-2 pandemic. Methods: We conducted a prospective cohort study of adults hospitalised with CAP at three UK sites between 2018 and 2020. Pneumococcal serotypes were identified using a 24-valent urinary-antigen assay and blood cultures. Risk factors associated with vaccine-type pneumonia caused by serotypes in the 13-, 15- and 20-valent pneumococcal conjugate vaccines (PCV13, PCV15, PCV20) and 23-valent pneumococcal polysaccharide vaccine (PPV23) were determined from multivariable analysis. Findings: Of 1921 adults hospitalised with CAP, 781 (40.7%, 95% confidence intervals (CI) 38.5-42.9%) had pneumococcal pneumonia. A single PCV13-serotype was detected in 242 (31.0%, 95% CI 27.8-34.3%) pneumococcal CAP patients, mostly serotype 3 (171/242, 70.7%, 95% CI 64.5-76.0%). The additional two PCV15-serotypes were detected in 31 patients (4%, 95% CI 2.8-5.6%), and PCV20-non13-serotypes in 192 (24.6%), with serotype 8 most prevalent (123/192, 64.1%, 95% CI 57.1-70.5%). Compared to PCV13-serotype CAP, people with PCV20-non13 CAP were younger (median age 62 versus 72 years, p < 0.001) and less likely to be male (44% versus 61%, p = 0.01). PPV23-non13-serotypes were found in 252 (32.3%, 95% CI 29.1-35.6%) pneumococcal CAP patients. Interpretation: Despite mature infant pneumococcal programmes, the burden of PCV13-serotype pneumonia remains high in older adults, mainly due to serotype 3. PCV20-non13-serotype pneumonia is more likely in younger people with fewer pneumococcal risk factors. Funding: Unrestricted investigator-initiated research grant from Pfizer, United Kingdom; support from National Institute for Health Research (NIHR) Biomedical Research Centre, Nottingham.

Readmission following hospital admission for community-acquired pneumonia in England.

INTRODUCTION: Readmission rates following hospital admission with community-acquired pneumonia (CAP) have increased in the UK over the past decade. The aim of this work was to describe the cohort of patients with emergency 30-day readmission following hospitalisation for CAP in England and explore the reasons for this. METHODS: A retrospective analysis of cases from the British Thoracic Society national adult CAP audit admitted to hospitals in England with CAP between 1 December 2018 and 31 January 2019 was performed. Cases were linked with corresponding patient level data from Hospital Episode statistics, providing data on the primary diagnosis treated during readmission and mortality. Analyses were performed describing the cohort of patients readmitted within 30 days, reasons for readmission and comparing those readmitted and primarily treated for pneumonia with other diagnoses. RESULTS: Of 8136 cases who survived an index admission with CAP, 1304 (15.7%) were readmitted as an emergency within 30 days of discharge. The main problems treated on readmission were pneumonia in 516 (39.6%) patients and other respiratory disorders in 284 (21.8%). Readmission with pneumonia compared with all other diagnoses was associated with significant inpatient mortality (15.9% vs 6.5%; aOR 2.76, 95% CI 1.86 to 4.09, p<0.001). A diagnosis of hospital-acquired infection was more frequent in readmissions treated for pneumonia than other diagnoses (22.1% vs 3.9%, p<0.001). CONCLUSION: Pneumonia is the most common condition treated on readmission following hospitalisation with CAP and carries a higher mortality than both the index admission or readmission due to other diagnoses. Strategies to reduce readmissions due to pneumonia are required.

Incidence of cognitive impairment and dementia after hospitalisation for pneumonia: a UK population-based matched cohort study.

Background: Survivors of common infections may develop cognitive impairment or dementia; however, the risk of these conditions in people hospitalised with pneumonia is not well established. Methods: A matched cohort study was conducted using Hospital Episode Statistics (HES) data linked to the Clinical Practice Research Database (CPRD). Adults with the first International Classification of Diseases (10th Revision) code for pneumonia recorded in the HES between 1 July 2002 and 30 June 2017 were included, and up to four controls without hospitalisation for pneumonia in the CPRD were matched by sex, age and practice. Cognitive impairment and dementia incidence rates were calculated and survival analysis was performed comparing those hospitalised with pneumonia to the general population. Results: The incidence rates of cognitive impairment and dementia were 18 (95% CI 17.3-18.7) and 13.2 (95% CI 13-13.5) per 1000 person-years among persons previously hospitalised with pneumonia and the matched cohort respectively. People previously hospitalised with pneumonia had 53% higher incidence of cognitive impairment and dementia (adjusted hazard ratio (aHR) 1.53, 95% CI 1.46-1.61) than their matched cohort. The highest incidence was observed within 1 year of hospitalisation for pneumonia compared to the general population (aHR 1.89, 95% CI 1.75-2.05). Age modified the effect of hospitalisation for pneumonia on cognitive impairment and dementia such that the size of effect was stronger in people between 45 and 60 years old (p-value for interaction <0.0001). Conclusion: Cognitive impairment and dementia are more likely to be diagnosed in people who have been hospitalised for pneumonia, especially in the first year after discharge, than in the general population.

Impact of social deprivation on clinical outcomes of adults hospitalised with community-acquired pneumonia in England: a retrospective cohort study.

INTRODUCTION: Socioeconomic deprivation has been associated with an increased incidence of infection and poorer clinical outcomes during influenza pandemics and the COVID-19 pandemic. The aim of this study was to determine the relationship between deprivation and adverse clinical outcomes following hospital admission with community-acquired pneumonia (CAP), specifically 30-day all-cause mortality and non-elective hospital readmission. METHODS: Data from the British Thoracic Society national CAP audit on patients admitted to hospital with CAP in England between 1 December 2018 and 31 January 2019 were linked to patient-level Hospital Episode Statistics data and Index of Multiple Deprivation (IMD) scores. Multivariable logistic regression models were used to examine the association between deprivation and (a) 30-day mortality and (b) 30-day readmission with p values for trend reported. Age was examined as a potential effect modifier on the effect of IMD quintile on mortality and subsequent subanalysis in those <65 and ≥65 years was performed. RESULTS: Of 9165 adults admitted with CAP, 24.7% (n=2263) were in the most deprived quintile. No significant trend between deprivation and mortality was observed (p trend=0.38); however, the association between deprivation and mortality differed by age group. In adults aged<65 years, 30-day mortality was highest in the most deprived and lowest in the least deprived quintiles (4.4% vs 2.5%, aOR 1.83, 95% CI 0.84 to 4.0) with a significant trend across groups (p trend=0.04). Thirty-day readmission was highest in the most deprived quintile (17.1%) with a significant p trend across groups (p trend 0.003). Age-adjusted odds of readmission were highest in the most deprived compared with the least deprived (aOR 1.41, 95% CI 1.16 to 1.73). CONCLUSIONS: In adults aged<65 years hospitalised with CAP in England, mortality varied inversely with indices of social deprivation. There was also a significant association between deprivation and 30-day readmission. Strategies are required to decrease health inequalities in pneumonia mortality and hospital readmissions associated with deprivation.

Dietary nitrate supplementation for preventing and reducing the severity of winter infections, including COVID-19, in care homes (BEET-Winter): a randomised placebo-controlled feasibility trial.

PURPOSE: Infections cause considerable care home morbidity and mortality. Nitric oxide (NO) has broad-spectrum anti-viral, bacterial and yeast activity in vitro. We assessed the feasibility of supplementing dietary nitrate (NO substrate) intake in care home residents. METHODS: We performed a cluster-randomised placebo-controlled trial in UK residential and nursing care home residents and compared nitrate containing (400 mg) versus free (0 mg daily) beetroot juice given for 60 days. Outcomes comprised feasibility of recruitment, adherence, salivary and urinary nitrate, and ordinal infection/clinical events. RESULTS: Of 30 targeted care homes in late 2020, 16 expressed interest and only 6 participated. 49 residents were recruited (median 8 [interquartile range 7-12] per home), mean (standard deviation) age 82 (8) years, with proxy consent 41 (84%), advance directive for hospital non-admission 8 (16%) and ≥ 1 doses of COVID-19 vaccine 37 (82%). Background dietary nitrate was < 30% of acceptable daily intake. 34 (76%) residents received > 50% of juice. Residents randomised to nitrate vs placebo had higher urinary nitrate levels, median 50 [18-175] v 18 [10-50] mg/L, difference 25 [0-90]. Data paucity precluded clinical between-group comparisons; the outcome distribution was as follows: no infection 32 (67%), uncomplicated infection 0, infection requiring healthcare support 11 (23%), all-cause hospitalisation 5 (10%), all-cause mortality 0. Urinary tract infections were most common. CONCLUSIONS: Recruiting UK care homes during the COVID-19 pandemic was partially successful. Supplemented dietary nitrate was tolerated and elevated urinary nitrate. Together, infections, hospitalisations and deaths occurred in 33% of residents over 60 days. A larger trial is now required. TRIAL REGISTRATION: ISRCTN51124684. Application date 7/12/2020; assignment date 13/1/2021.

The COVID-19 pandemic has highlighted the need to invest in care home research infrastructure.

The COVID-19 pandemic resulted in catastrophic levels of morbidity and mortality for care home residents. Despite this, research platforms for COVID-19 in care homes arrived late in the pandemic compared with other care settings. The Prophylactic Therapy in Care Homes Trial (PROTECT-CH) was established to provide a platform to deliver multi-centre cluster-randomized clinical trials of investigational medicinal products for COVID-19 prophylaxis in UK care homes. Commencing set-up in January 2021, this involved the design and development of novel infrastructure for contracting and recruitment, remote consent, staff training, research insurance, eligibility screening, prescribing, dispensing and adverse event reporting; such infrastructure being previously absent. By the time this infrastructure was in place, the widespread uptake of vaccination in care homes had changed the epidemiology of COVID-19 rendering the trial unfeasible. While some of the resources developed through PROTECT-CH will enable the future establishment of care home platform research, the near absence of care home trial infrastructure and nationally linked databases involving the care home sector will continue to significantly hamper progress. These issues are replicated in most other countries. Beyond COVID-19, there are many other research questions that require addressing to provide better care to people living in care homes. PROTECT-CH has exposed a clear need for research funders to invest in, and legislate for, an effective care home research infrastructure as part of national pandemic preparedness planning. Doing so would also invigorate care home research in the interim, leading to improved healthcare delivery specific to those living in this sector.

Non-invasive pneumococcal pneumonia due to vaccine serotypes: A systematic review and meta-analysis.

BACKGROUND: Non-invasive pneumococcal pneumonia causes significant morbidity and mortality in older adults. Understanding pneumococcal sero-epidemiology in adults ≥50 years is necessary to inform vaccination policies and the updating of pneumococcal vaccines. METHODS: We conducted a systematic review and random-effects meta-analysis to determine the proportion of community-acquired pneumonia (CAP) in people ≥50 years due to pneumococcus and the proportion caused by pneumococcal vaccine serotypes. We searched MEDLINE, EMBASE and PubMed from 1 January 1990 to 30 March 2021. Heterogeneity was explored by subgroup analysis according to a) patient group (stratified versus age) and depth of testing, b) detection/serotyping method, and c) continent. The protocol is registered with PROSPERO (CRD42020192002). FINDINGS: Twenty-eight studies were included (34,216 patients). In the period 1-5 years after introduction of childhood PCV10/13 immunisation, 18% of CAP cases (95% CI 13-24%) were attributable to pneumococcus, with 49% (43-54%) of pneumococcal CAP due to PCV13 serotypes. The estimated proportion of pneumococcal CAP was highest in one study that used 24-valent serotype-specific urinary-antigen detection (ss-UAD)(30% [28-31%]), followed by studies based on diagnostic serology (28% [24-33%]), PCR (26% [15-37%]), ss-UAD14 (17% [13-22%]), and culture alone (14% [10-19%]). A higher estimate was observed in Europe (26% [21-30%] than North America (11% [9-12%](p<0·001). PCV13-serotype estimates were also influenced by serotyping methods. INTERPRETATION: Non-invasive pneumococcal CAP and vaccine-type pneumococcal CAP remains a burden in older adults despite widespread introduction of pneumococcal infant immunisation. Studies heavily reliant on ss-UADs restricted to vaccine-type serotypes may overestimate the proportion of potentially vaccine-preventable pneumococcal pneumonia. Sero-epidemiological data from low-income countries are lacking.

Effects of tobacco smoking on recurrent hospitalisation with pneumonia: a population-based cohort study.

The incidence of and risk factors for recurrent hospitalisation for pneumonia were investigated using data from Hospital Episode Statistics, linked to a UK primary care database. Within 90 days and 1 year of follow-up, 1733 (3.1%) and 5064 (9.0%), developed recurrent pneumonia respectively. Smoking status at the time of hospitalisation with index pneumonia was associated with the risk of readmission with recurrent pneumonia within a year of discharge: current versus never smokers: adjusted subhazard ratio (sHR) 1.42, 95% CI 1.32 to 1.53, p<0.001, and ex smokers versus never smokers: adjusted sHR 1.24, 95% CI 1.15 to 1.34, p<0.001. Other independent risk factors associated with recurrent pneumonia were age, gender, deprivation and underlying comorbidities.

Splenic macrophages as the source of bacteraemia during pneumococcal pneumonia.

BACKGROUND: Severe community-acquired pneumococcal pneumonia is commonly associated with bacteraemia. Although it is assumed that the bacteraemia solely derives from pneumococci entering the blood from the lungs it is unknown if other organs are important in the pathogenesis of bacteraemia. Using three models, we tested the relevance of the spleen in pneumonia-associated bacteraemia. METHODS: We used human spleens perfused ex vivo to explore permissiveness to bacterial replication, a non-human primate model to check for splenic involvement during pneumonia and a mouse pneumonia-bacteraemia model to demonstrate that splenic involvement correlates with invasive disease. FINDINGS: Here we present evidence that the spleen is the reservoir of bacteraemia during pneumonia. We found that in the human spleen infected with pneumococci, clusters with increasing number of bacteria were detectable within macrophages. These clusters also were detected in non-human primates. When intranasally infected mice were treated with a non-therapeutic dose of azithromycin, which had no effect on pneumonia but concentrated inside splenic macrophages, bacteria were absent from the spleen and blood and importantly mice had no signs of disease. INTERPRETATION: We conclude that the bacterial load in the spleen, and not lung, correlates with the occurrence of bacteraemia. This supports the hypothesis that the spleen, and not the lungs, is the major source of bacteria during systemic infection associated with pneumococcal pneumonia; a finding that provides a mechanistic basis for using combination therapies including macrolides in the treatment of severe community-acquired pneumococcal pneumonia. FUNDING: Oxford University, Wolfson Foundation, MRC, NIH, NIHR, and MRC and BBSRC studentships supported the work.

Long Covid in adults discharged from UK hospitals after Covid-19: A prospective, multicentre cohort study using the ISARIC WHO Clinical Characterisation Protocol.

BACKGROUND: This study sought to establish the long-term effects of Covid-19 following hospitalisation. METHODS: 327 hospitalised participants, with SARS-CoV-2 infection were recruited into a prospective multicentre cohort study at least 3 months post-discharge. The primary outcome was self-reported recovery at least ninety days after initial Covid-19 symptom onset. Secondary outcomes included new symptoms, disability (Washington group short scale), breathlessness (MRC Dyspnoea scale) and quality of life (EQ5D-5L). FINDINGS: 55% of participants reported not feeling fully recovered. 93% reported persistent symptoms, with fatigue the most common (83%), followed by breathlessness (54%). 47% reported an increase in MRC dyspnoea scale of at least one grade. New or worse disability was reported by 24% of participants. The EQ5D-5L summary index was significantly worse following acute illness (median difference 0.1 points on a scale of 0 to 1, IQR: -0.2 to 0.0). Females under the age of 50 years were five times less likely to report feeling recovered (adjusted OR 5.09, 95% CI 1.64 to 15.74), were more likely to have greater disability (adjusted OR 4.22, 95% CI 1.12 to 15.94), twice as likely to report worse fatigue (adjusted OR 2.06, 95% CI 0.81 to 3.31) and seven times more likely to become more breathless (adjusted OR 7.15, 95% CI 2.24 to 22.83) than men of the same age. INTERPRETATION: Survivors of Covid-19 experienced long-term symptoms, new disability, increased breathlessness, and reduced quality of life. These findings were present in young, previously healthy working age adults, and were most common in younger females. FUNDING: National Institute for Health Research, UK Medical Research Council, Wellcome Trust, Department for International Development and the Bill and Melinda Gates Foundation.

Co-infection in critically ill patients with COVID-19: an observational cohort study from England.

Introduction. During previous viral pandemics, reported co-infection rates and implicated pathogens have varied. In the 1918 influenza pandemic, a large proportion of severe illness and death was complicated by bacterial co-infection, predominantly Streptococcus pneumoniae and Staphylococcus aureus.Gap statement. A better understanding of the incidence of co-infection in patients with COVID-19 infection and the pathogens involved is necessary for effective antimicrobial stewardship.Aim. To describe the incidence and nature of co-infection in critically ill adults with COVID-19 infection in England.Methodology. A retrospective cohort study of adults with COVID-19 admitted to seven intensive care units (ICUs) in England up to 18 May 2020, was performed. Patients with completed ICU stays were included. The proportion and type of organisms were determined at <48 and >48 h following hospital admission, corresponding to community and hospital-acquired co-infections.Results. Of 254 patients studied (median age 59 years (IQR 49-69); 64.6 % male), 139 clinically significant organisms were identified from 83 (32.7 %) patients. Bacterial co-infections/ co-colonisation were identified within 48 h of admission in 14 (5.5 %) patients; the commonest pathogens were Staphylococcus aureus (four patients) and Streptococcus pneumoniae (two patients). The proportion of pathogens detected increased with duration of ICU stay, consisting largely of Gram-negative bacteria, particularly Klebsiella pneumoniae and Escherichia coli. The co-infection/ co-colonisation rate >48 h after admission was 27/1000 person-days (95 % CI 21.3-34.1). Patients with co-infections/ co-colonisation were more likely to die in ICU (crude OR 1.78,95 % CI 1.03-3.08, P=0.04) compared to those without co-infections/ co-colonisation.Conclusion. We found limited evidence for community-acquired bacterial co-infection in hospitalised adults with COVID-19, but a high rate of Gram-negative infection acquired during ICU stay.

The feasibility and tolerability of using inspiratory muscle training with adults discharged from the hospital with community-acquired pneumonia.

INTRODUCTION: Patients experience substantial morbidity following discharge from hospital and during recovery from communi-ty-acquired pneumonia (CAP). Inspiratory muscle training (IMT) has demonstrated improved functional capacity and reduced patient-reported symptoms. To date the safety and tolerability of these methods have not been determined in CAP patients recovering following hospitalization. Accordingly, this study aimed to assess the safety and tolerability of IMT in adults discharged from hospital with CAP. MATERIAL AND METHODS: Participants received an IMT device (POWERbreathe KHP2) and completed 9-weeks IMT training with weekly follow-up. Frequency (twice daily) and load (50% PImax) were fixed throughout, but training volume increased incrementally (2-week habituation phase, 7-week training phase). Primary outcomes of interest included IMT safety and tolerability. RESULTS: Twenty-two participants were recruited; 16 were male, mean age 55.2 years (range 27.9-77.3). From 1183 possible training days, side effects were reported on 15 occasions by 10 individual participants. All reported side-effects were assessed as grade 1 and did not prevent further training. Participant-reported IMT acceptability was 99.4%. CONCLUSION: Inspiratory muscle training is safe and tolerable in patients following hospitalisation for CAP. Patient satisfaction with IMT is high and it is viewed by patients as being helpful in their recovery. Distinguishing CAP-related symptoms and device-related side effects is challenging. Symptom prevalence declined during follow-up with concurrent improvements in spirometry observed. Further research is required to determine the efficacy of IMT interventions following CAP and other acute respiratory infections.

Primary care consultations after hospitalisation for pneumonia: a large population-based cohort study.

BACKGROUND: Up to 70% of patients report ongoing symptoms 4 weeks after hospitalisation for pneumonia; the impact on primary care is poorly understood. AIM: To investigate the frequency of primary care consultations after hospitalisation for pneumonia, and the reasons for consultation. DESIGN AND SETTING: A population-based cohort study in England using a UK primary care database of anonymised medical records (Clinical Practice Research Datalink [CPRD]) linked to Hospital Episode Statistics (HES). METHOD: Adults with the first International Classification of Diseases, 10th Revision (ICD-10) code for pneumonia (J12-J18) recorded in HES between July 2002 and June 2017 were included. Primary care consultation within 30 days of discharge was identified as the recording of any medical Read code (excluding administration-related codes) in CPRD. Competing-risks regression analyses were conducted to determine the predictors of consultation and antibiotic use at consultation; death and readmission were competing events. Reasons for consultation were examined. RESULTS: Of 56 396 adults, 55.9% (n = 31 542) consulted primary care within 30 days of hospital discharge. The rate of consultation was highest within 7 days (4.7 per 100 person-days). The strongest predictor for consultation was a higher number of primary care consultations in the year before index admission (adjusted subhazard ratio [sHR] 8.98, 95% confidence interval [CI] = 6.42 to 12.55). The most common reason for consultation was for a respiratory disorder (40.7%, n = 12 840), 11.8% for pneumonia specifically. At consultation, 31.1% (n = 9823) received further antibiotics. Penicillins (41.6%, n = 5753/13 829) and macrolides (21.9%, n = 3029/13 829) were the most common antibiotics prescribed. CONCLUSION: Following hospitalisation for pneumonia, a significant proportion of patients consulted primary care within 30 days, highlighting the morbidity experienced by patients during recovery from pneumonia.

What is the recovery rate and risk of long-term consequences following a diagnosis of COVID-19? A harmonised, global longitudinal observational study protocol.

INTRODUCTION: Very little is known about possible clinical sequelae that may persist after resolution of acute COVID-19. A recent longitudinal cohort from Italy including 143 patients followed up after hospitalisation with COVID-19 reported that 87% had at least one ongoing symptom at 60-day follow-up. Early indications suggest that patients with COVID-19 may need even more psychological support than typical intensive care unit patients. The assessment of risk factors for longer term consequences requires a longitudinal study linked to data on pre-existing conditions and care received during the acute phase of illness. The primary aim of this study is to characterise physical and psychosocial sequelae in patients post-COVID-19 hospital discharge. METHODS AND ANALYSIS: This is an international open-access prospective, observational multisite study. This protocol is linked with the International Severe Acute Respiratory and emerging Infection Consortium (ISARIC) and the WHO's Clinical Characterisation Protocol, which includes patients with suspected or confirmed COVID-19 during hospitalisation. This protocol will follow-up a subset of patients with confirmed COVID-19 using standardised surveys to measure longer term physical and psychosocial sequelae. The data will be linked with the acute phase data. Statistical analyses will be undertaken to characterise groups most likely to be affected by sequelae of COVID-19. The open-access follow-up survey can be used as a data collection tool by other follow-up studies, to facilitate data harmonisation and to identify subsets of patients for further in-depth follow-up. The outcomes of this study will inform strategies to prevent long-term consequences; inform clinical management, interventional studies, rehabilitation and public health management to reduce overall morbidity; and improve long-term outcomes of COVID-19. ETHICS AND DISSEMINATION: The protocol and survey are open access to enable low-resourced sites to join the study to facilitate global standardised, longitudinal data collection. Ethical approval has been given by sites in Colombia, Ghana, Italy, Norway, Russia, the UK and South Africa. New sites are welcome to join this collaborative study at any time. Sites interested in adopting the protocol as it is or in an adapted version are responsible for ensuring that local sponsorship and ethical approvals in place as appropriate. The tools are available on the ISARIC website (www.isaric.org). PROTOCOL REGISTRATION NUMBER: osf.io/c5rw3/ PROTOCOL VERSION: 3 August 2020 EUROQOL ID: 37035.

Nitric oxide for the prevention and treatment of viral, bacterial, protozoal and fungal infections.

Although the antimicrobial potential of nitric oxide (NO) is widely published, it is little used clinically. NO is a key signalling molecule modulating vascular, neuronal, inflammatory and immune responses. Endogenous antimicrobial activity is largely mediated by high local NO concentrations produced by cellular inducible nitric oxide synthase, and by derivative reactive nitrogen oxide species including peroxynitrite and S-nitrosothiols. NO may be taken as dietary substrate (inorganic nitrate, L-arginine), and therapeutically as gaseous NO, and transdermal, sublingual, oral, intranasal and intravenous nitrite or nitrate. Numerous preclinical studies have demonstrated that NO has generic static and cidal activities against viruses (including ß-coronaviruses such as SARS-CoV-2), bacteria, protozoa and fungi/yeasts  in vitro. Therapeutic effects have been seen in animal models  in vivo, and phase II trials have demonstrated that NO donors can reduce microbial infection. Nevertheless, excess NO, as occurs in septic shock, is associated with increased morbidity and mortality. In view of the dose-dependent positive and negative effects of NO, safety and efficacy trials of NO and its donors are needed for assessing their role in the prevention and treatment of infections. Trials should test dietary inorganic nitrate for pre- or post-exposure prophylaxis and gaseous NO or oral, topical or intravenous nitrite and nitrate for treatment of mild-to-severe infections, including due to SARS-CoV-2 (COVID-19). This review summarises the evidence base from  in vitro, in vivo and early phase clinical studies of NO activity in viral, bacterial, protozoal and fungal infections.