Nicotine patches in patients on mechanical ventilation for severe COVID-19: a randomized, double-blind, placebo-controlled, multicentre trial

Systematic review and meta analysis of cross immunity and the smokers paradox in COVID19

COVID-19 pandemic, caused by the novel SARS-CoV-2 virus, has raised significant interest in understanding potential cross-immunity mechanisms. Recent evidence suggests that T-cells associated with common cold coronaviruses (229E, NL63, OC43, HKU1) may provide some level of cross-immunity against SARS-CoV-2. It is also known that the prevalence of smokers among patients admitted to hospital for COVID-19 is lower than expected according to the corresponding country's smoking prevalence, which is known as smoker's paradox in COVID-19. No clear consensus to explain it has yet been reached. This phenomenon suggests a complex interaction between smoking and immune response. Nonetheless, very few works have studied the prevalence of smokers in those infected by common cold coronaviruses, and its relation to COVID-19 has not been investigated. We performed a systematic review and meta-analysis to study the prevalence of smokers among patients infected by common cold coronaviruses, and to compare them to the corresponding country's smoking prevalence. L'Abbé plots were used to visually assess the consistency of the observed effects across the different studies included in the meta-analysis. Additionally, significant differences were found in smoking prevalence among the various types of ccCoV, indicating the need for further research into the biological mechanisms driving these disparities. The results show that smoking prevalence is higher among those patients infected by these coronaviruses than in the general population (OR = 1.37, 95% CI: 0.81-2.33). A study was separately done for the four coronavirus types, and the prevalence of smokers was higher in three of the four than that corresponding to country, gender and study year: OC43 (OR = 1.93, 95% CI: 0.64-5.82); HKU1 (OR = 3.62, 95% CI: 1.21-10.85); NL63 (OR = 1.93, 95% CI: 0.64-5.82); 229E (OR = 0.97, 95% CI: 0.50-1.90). The heterogeneity of the studies was assessed using the Cochrane Chi-squared test, I-squared (I2), and Tau-squared (τ2). This detailed statistical analysis enhances the robustness of our findings and highlights the variations in smoking prevalence among different ccCoVs. Our data suggest that COVID-19 might be less prevalent among smokers due to greater cross-immunity from a larger number or more recent infections by common cold coronaviruses than the non-smoking population, which would explain smoker's paradox in COVID-19. IMPLICATIONS. The low prevalence of current smokers among SARS-CoV-2 patients is a finding recurrently repeated, even leading to postulate the "smoker's paradox" in COVID-19. This fact compelled us to study the prevalence of smokers among patients infected by common cold coronaviruses, and to compare them to the corresponding country's smoking prevalence. Our data could explain smoker's paradox in COVID-19 by a greater cross immunity due to a larger number, or more recent infections by common cold coronaviruses than the non-smoking population. This manuscript allow understand potential unrevealed mechanism for low prevalence of current smokers among SARS-CoV-2 patients.

Nicotine exposure decreases likelihood of SARS-CoV-2 RNA expression and neuropathology in the hACE2 mouse brain but not moribundity

Individuals infected by SARS-CoV-2 are at risk of developing neurological-related post-acute disorders. Disputed epidemiological data indicated nicotine may reduce the severity of infection. Here we find exposure to nicotine in drinking water does not alter the moribundity of hACE2 mice. However, pre-exposure to nicotine decreased the likelihood of SARS-CoV-2 RNA expression and pathology in the brain. These results suggest mechanisms involving targets of nicotine could be leveraged to prevent the neurovirulence of SARS-CoV-2.

Current tobacco use and COVID-19 diagnoses in a cohort of adult clients of public dental clinics in Sweden

Smoking has been linked with both increased and decreased risk of COVID-19, prompting the hypothesis of a protective role of nicotine in the pathogenesis of the disease. Studies of the association between use of smokeless tobacco and COVID-19 would help refining this hypothesis. We analysed data from 424,386 residents in the Stockholm Region, Sweden, with information on smoking and smokeless tobacco (snus) use prior to the pandemic obtained from dental records. Diagnoses of COVID-19 between February and October 2020 were obtained from health-care registers. We estimated the risk of receiving a diagnosis of COVID-19 for current smokers and for current snus users relative to non-users of tobacco, adjusting for potential confounders (aRR). The aRR of COVID -19 was elevated for current snus users (1.09 ;95%CI = 0.99-1.21 among men and 1.15; 95%CI = 1.00-1.33 among women). The risk for women consuming more than 1 can/day was twice as high as among non-users of tobacco. Current smoking was negatively associated with risk of COVID-19 (aRR = 0.68; 95% CI = 0.61-0.75); including hospital admission (aRR = 0.60; 95% CI = 0.47-0.76) and intensive care (aRR = 0.43; 95% CI = 0.21-0.89). The hypothesis of a protective effect of tobacco nicotine on COVID-19 was not supported by the findings. The negative association between smoking and COVID-19 remains unexplained.

Nicotine exposure decreases likelihood of SARS-CoV-2 RNA expression and neuropathology in the hACE2 mouse brain but not moribundity

Individuals infected by SARS-CoV-2 are at risk of developing neurological-related post-acute disorders. Disputed epidemiological data indicated nicotine may reduce the severity of infection. Here we find exposure to nicotine in drinking water does not alter the moribundity of hACE2 mice. However, pre-exposure to nicotine decreased the likelihood of SARS-CoV-2 RNA expression and pathology in the brain. These results suggest mechanisms involving targets of nicotine could be leveraged to prevent the neurovirulence of SARS-CoV-2.

Assessment of plasma Catestatin in COVID-19 reveals a hitherto unknown inflammatory activity with impact on morbidity-mortality

Introduction

Neuroendocrine cells release Catestatin (CST) from Chromogranin A (CgA) to regulate stress responses. As regards COVID-19 patients (COVID+) requiring oxygen supply, to date nobody has studied CST as a potential mediator in the regulation of immunity.

Patients & Methods

Admission plasma CST and CgA - its precursor - concentrations were measured (ELISA test) in 73 COVID+ and 27 controls. Relationships with demographics, comorbidities, disease severity and outcomes were analysed (Mann-Whitney, Spearman correlation tests, ROC curves).

Results

Among COVID+, 49 required ICU-admission (COVID+ICU+) and 24 standard hospitalization (COVID+ICU-). Controls were either healthy staff (COVID-ICU-, n=11) or COVID-ICU+ patients (n=16). Median plasma CST were higher in COVID+ than in controls (1.6 [1.02; 3.79] vs 0.87 [0.59; 2.21] ng/mL, p<0.03), with no difference between COVID+ and COVID-ICU+. There was no difference between groups in either CgA or CST/CgA ratios, but these parameters were lower in healthy controls (p<0.01). CST did not correlate with either hypoxia- or usual inflammation-related parameters. In-hospital mortality was similar whether COVID+ or not, but COVID+ had longer oxygen support and more complications (p<0.03). CST concentrations and the CST/CgA ratio were associated with in-hospital mortality (p<0.01) in COVID+, whereas CgA was not. CgA correlated with care-related infections (p<0.001).

Conclusion

Respiratory COVID patients release significant amounts of CST in the plasma making this protein widely available for the neural regulation of immunity. If confirmed prospectively, plasma CST will reliably help in predicting in-hospital mortality, whereas CgA will facilitate the detection of patients prone to care-related infections.

Assessing Smoking Status and Risk of SARS-CoV-2 Infection: A Machine Learning Approach among Veterans

The role of smoking in the risk of SARS-CoV-2 infection is unclear. We used a retrospective cohort design to study data from veterans’ Electronic Medical Record to assess the impact of smoking on the risk of SARS-CoV-2 infection. Veterans tested for the SARS-CoV-2 virus from 02/01/2020 to 02/28/2021 were classified as: Never Smokers (NS), Former Smokers (FS), and Current Smokers (CS). We report the adjusted odds ratios (aOR) for potential confounders obtained from a cascade machine learning algorithm. We found a 19.6% positivity rate among 1,176,306 veterans tested for SARS-CoV-2 infection. The positivity proportion among NS (22.0%) was higher compared with FS (19.2%) and CS (11.5%). The adjusted odds of testing positive for CS (aOR:0.51; 95%CI: 0.50, 0.52) and FS (aOR:0.89; 95%CI:0.88, 0.90) were significantly lower compared with NS. Four pre-existing conditions, including dementia, lower respiratory infections, pneumonia, and septic shock, were associated with a higher risk of testing positive, whereas the use of the decongestant drug phenylephrine or having a history of cancer were associated with a lower risk. CS and FS compared with NS had lower risks of testing positive for SARS-CoV-2. These findings highlight our evolving understanding of the role of smoking status on the risk of SARS-CoV-2 infection.

Comparison of Clinical Profiles and Mortality Outcomes Between Influenza and COVID-19 Patients Invasively Ventilated in the ICU: A Retrospective Study From All Paris Public Hospitals From 2016 to 2021

Studies comparing outcomes of ICU patients admitted for either COVID-19 or seasonal influenza are limited. Our objective was to describe baseline clinical profiles, care procedures, and mortality outcomes by infection status (influenza vs COVID-19) of patients who received invasive mechanical ventilation in the ICU.