Guidelines from the CDC and the WHO recommend the wearing of face masks to prevent the spread of coronavirus (CoV) disease 2019 (COVID-19); however, the protective efficiency of such masks against airborne transmission of infectious severe acute respiratory syndrome CoV-2 (SARS-CoV-2) droplets/aerosols is unknown. Here, we developed an airborne transmission simulator of infectious SARS-CoV-2-containing droplets/aerosols produced by human respiration and coughs and assessed the transmissibility of the infectious droplets/aerosols and the ability of various types of face masks to block the transmission. We found that cotton masks, surgical masks, and N95 masks all have a protective effect with respect to the transmission of infective droplets/aerosols of SARS-CoV-2 and that the protective efficiency was higher when masks were worn by a virus spreader. Importantly, medical masks (surgical masks and even N95 masks) were not able to completely block the transmission of virus droplets/aerosols even when completely sealed. Our data will help medical workers understand the proper use and performance of masks and determine whether they need additional equipment to protect themselves from infected patients. IMPORTANCE Airborne simulation experiments showed that cotton masks, surgical masks, and N95 masks provide some protection from the transmission of infective SARS-CoV-2 droplets/aerosols; however, medical masks (surgical masks and even N95 masks) could not completely block the transmission of virus droplets/aerosols even when sealed.

a b s t r a c t Background: Coronavirus 229E (HCoV-229E), one of the causes of the common cold, exacerbates chronic obstructive pulmonary disease (COPD) and bronchial asthma. Longacting muscarinic antagonists and b 2 -agonists and inhaled corticosteroids inhibit the exacerbation of COPD and bronchial asthma caused by infection with viruses, including Please cite this article as: Yamaya M et al., Inhibitory effects of glycopyrronium, formoterol, and budesonide on coronavirus HCoV-229E replication and cytokine production by primary cultures of human nasal and tracheal epithelial cells, Respiratory Investigation, https:// Available online xxx Keywords: Airway epithelial cells HCoV-229E CD13 Long-acting b 2 agonist Long-acting muscarinic antagonist HCoV-229E. However, the effects of these drugs on HCoV-229E replication and infectioninduced inflammation in the human airway are unknown. Methods: Primary human nasal (HNE) and tracheal (HTE) epithelial cell cultures were infected with HCoV-229E. Results: Pretreatment of HNE and HTE cells with glycopyrronium or formoterol decreased viral RNA levels and/or titers, the expression of the HCoV-229E receptor CD13, the number and fluorescence intensity of acidic endosomes where HCoV-229E RNA enters the cytoplasm, and the infection-induced production of cytokines, including IL-6, IL-8, and IFN-b.Treatment of the cells with the CD13 inhibitor 2 0 2 0 -dipyridyl decreased viral titers.Pretreatment of the cells with a combination of three drugs (glycopyrronium, formoterol, and budesonide) exerted additive inhibitory effects on viral titers and cytokine production.Pretreatment of HNE cells with glycopyrronium or formoterol reduced the susceptibility to infection, and pretreatment with the three drugs inhibited activation of nuclear factorkappa B p50 and p65 proteins. Pretreatment with formoterol increased cAMP levels and treatment with cAMP decreased viral titers, CD13 expression, and the fluorescence intensity of acidic endosomes.Conclusions: These findings suggest that glycopyrronium, formoterol, and a combination of glycopyrronium, formoterol, and budesonide inhibit HCoV-229E replication partly by inhibiting receptor expression and/or endosomal function and that these drugs modulate infection-induced inflammation in the airway.

To examine the effects of erythromycin on rhinovirus (RV) infection in airway epithelium, primary cultures of human tracheal epithelial cells were infected with the RV major subgroup, RV14, and the minor subgroup, RV2. Infection was confirmed by increases in viral RNA of the infected cells and viral titers of the supernatants. RV14 upregulated the expression of the mRNA and protein of intercellular adhesion molecule-1 (ICAM-1), the major RV receptor, and it increased the cytokine production. Erythromycin reduced the supernatant RV14 titers, RV14 RNA, the susceptibility to RV14 infection, and the production of ICAM-1 and cytokines. Erythromycin also reduced the supernatant RV2 titers, RV2 RNA, the susceptibility to RV2 infection, and cytokine production, although the inhibitory effects of erythromycin on the expression of the low-density lipoprotein receptor, the minor RV receptor, were small. Erythromycin reduced the nuclear factor-kappaB activation by RV14 and decreased the number of acidic endosomes in the epithelial cells. These results suggest that erythromycin inhibits infection by the major RV subgroup by reducing ICAM-1 and infection by both RV subgroups by blocking the RV RNA entry into the endosomes. Erythromycin may also modulate airway inflammation by reducing the production of proinflammatory cytokines and ICAM-1 induced by RV infection.