Nebulization and COVID-19:Is the risk of spread actual?

The airborne transmission of SARS-CoV-2 has been quickly suggested based on the stability of SARS-CoV-2 in aerosol for 3 hours. Nebulization, by a possible microorganisms contamination and/or by the aerosolization of contaminated particles, may expose health care workers. Thus, various guidelines on nebulization emerged during the SARS-CoV-2 pandemic to ensure a maximal protection. This study aimed to address the risk of airborne transmission in patients hospitalized with severe COVID-19. Ten severe COVID-19 patients were recruited at the admission in the hospital. They were treated by nebulization with a standard single-use jet nebulizer operating at 8 L/min with a T piece connected to a mouthpiece and a filter. Immediately after the first nebulization, the residual solution of each nebulizer was sampled. Then, the nebulizers were refilled with isotonic saline solution to complete the residual volume. The filter was replaced by a BioSampler (SKC 20-mL) loaded with 20 mL phosphatebuffered saline and 0.5% bovine serum albumin. The nebulizer was driven by a compressed air supply, and a 10minnebulization was performed again on the bench. The emitted aerosol was continuously collected during the nebulization. The nominal and emitted dose were sampled. The SARS-CoV-2 viral load was quantified in all samples by RT-PCR. No SARS-CoV-2 RNA was found in any sample for all nebulizations. The result of this study shows no SARS-CoV-2 nebulizers contamination by COVID-19 patients at hospital and does not support the role of nebulizers in terms of aerosol virus dissemination in air. Nevertheless, exhaled virus by the patient itself remains and must be considered independently to the nebulizer.

Development of an alternative predictive model of aerosol deposition in macaque monkeys and associated means of administration

The respiratory system is a preferred entry point for pathogens and non-pathogens agents (pollens, dusts etc). Furthermore, the inhaled route is also used for the administration of therapeutics for the treatment of respiratory pathologies. Preclinical studies using animal models are essential and sometimes undisputable (development of inhale drugs, FDA rule) in order to study, understand and predict toxic and therapeutics aerosols effect in the upper and lower respiratory tract. In this context, the quantity of deposited aerosol and its distribution in the respiratory tract is a key factor influencing the results. Moreover, with the 21st century challenges regarding the SARS-COV-2 pandemic, potential air transmitted pathogens and increase of respiratory diseases, having robust tools to study aerosols deposition is necessary. The macaque has been identified as a relevant animal model in terms of anatomy, physiopathology for inhalation studies but the complexity and availability of this animal, make it, among other things, a valuable but difficult and expensive model to access It therefore appears necessary and fundamental to use alternative methods for preliminary studies without animal in order to reduce the number of animal studies and increase the quality of studies. In our project, we have developed an in vitro 3D model anatomical model of the macaque airway. We use a high precision CT-scans of Non-Human Primates and the 3D printing technique with stereolithography method. We have developed a refined in vitro 3D Cast model, which accurately mimics the upper airway of 3 macaques and the lower airway down to the second bronchial division. However, the 3D model needs to be validated. To validate this model, a comparative study between the aerosol deposition obtained with the 3D model and the deposition obtained with the three macaques was carried out by scintigraphy imaging. Aerosols will be generated using three nebulizers generating three different particle sizes in order to target and study three different deposition areas in the airways: the first nebulizer with a 10μm in terms of Volume Median Diameter (VMD) predicting a major deposition in the upper airways (90%), the second nebulizer with a 1, 35pm in terms of Mass Median Aerodynamic Diameter (MMAD) predicting a deposition in upper and lower airways (50%) and the third with a 0, 36pm of MMAD predicting a major deposition in lower airways (90%). If the 3D model is validated by the comparison between in vitro and in vivo results in terms of scintigraphy deposition measurement, it will allow to reduce the number of experiments on macaques and will participate to the improvement of the quality of studies.

Development of airways protection against respiratory nipah virus infection by inhalation of antiviral peptides

Introduction: Nipah virus (NiV) is a recently emerged zoonotic paramyxovirus, capable of inter-human transmission and listed byWHO among the top eight emerging pathogens, based on the probability of causing severe outbreaks and a pandemic potential. In humans, NiV induces acute respiratory distress and encephalitis with a lethality of 40-100%.Anovel antiviral approach, based on peptideswhich interferewith the fusion of NiV with host cells has been recently developed. Research hypothesis: The project aims to develop a new approach to administer aerosolized peptides capable of inhibiting respiratory NiV infection, which may be applied to the other respiratory viruses using similar fusion mechanism for viral entry. Methods: We have developed an inhalation strategy using nebulized antiviral peptide in African Green Monkey (AGM), an animal model shown to well reproduce human NiV infection. Results and discussion: A customized nebuliser with a specific mesh size and interface to produce an aerosol of peptides while ensuring the upkeep of >90% of antiviral activity after nebulisation was assessed. Lung deposition was measured by in vivo scintigraphy (8-16% in terms of nebulizer charge). Toxicology analysis in AGM demonstrated the absence of adverse lung findings from nebulised peptides after several consecutive administrations of 10 min. Immunofluorescence assays, using peptide specific antibodies on lung slices, revealed the presence of peptides along the respiratory tract 24 h after administration. Conclusion: Developed nebulisers are now ready for the first proof-of-concept study with the infectious NiV in a Biosafety level 4 laboratory. The results may open new perspectives for antiviral prevention against respiratory viruses and the strategy could be further extended to the ongoing SARS-CoV-2 outbreak (funded by DGAANR-Astrid-Maturation).

[Good practice for aerosol therapy by nebulization in 2020]. / Bonnes pratiques de l'aérosolthérapie par nébulisation en 2020.

Nebulization is a drug delivery mode whose prescription and application remain uncertain. A guide to good practice has been proposed by the work group on aerosol therapy of the French Society for Respiratory Diseases, so-called GAT. The previous recommendations date from 2007. In addition to an update of data on nebulization, these expert recommendations aim to be of real help to the prescriber.