medRxiv preprint Dear editor, 10The unprecedented pandemic of COVID-19 has created worldwide shortages of personal protective 11 equipment, in particular respiratory protection such as N95 respirators(1). SARS-CoV-2 transmission is 12 frequently occurring in hospital settings, with numerous reported cases of nosocomial transmission 13 highlighting the vulnerability of healthcare workers(2). The environmental stability of SARS-CoV-2 14 underscores the need for rapid and effective decontamination methods. In general, N95 respirators are 15 designed for single use prior to disposal. Extensive literature is available for decontamination procedures 16 for N95 respirators, using either bacterial spore inactivation tests, bacteria or respiratory viruses (e.g. 17 influenza A virus)(3-6). Effective inactivation methods for these pathogens and surrogates include UV, 18 ethylene oxide, vaporized hydrogen peroxide (VHP), gamma irradiation, ozone and dry heat(3-7). The 19 filtration efficiency and N95 respirator fit has typically been less well explored, but suggest that both 20 filtration efficiency and N95 respirator fit can be affected by the decontamination method used (7, 8). For 21 a complete list of references see supplemental information. 23Here, we analyzed four different decontamination methods -UV radiation (260 -285 nm), 70ºC dry heat, 24 70% ethanol and vaporized hydrogen peroxide (VHP) -for their ability to reduce contamination with 25 infectious SARS-CoV-2 and their effect on N95 respirator function. For each of the decontamination 26 methods, we compared the normal inactivation rate of SARS-CoV-2 on N95 filter fabric to that on 27 stainless steel, and we used quantitative fit testing to measure the filtration performance of the N95 28 respirators after each decontamination run and 2 hours of wear, for three consecutive decontamination 29 and wear sessions (see supplemental information). VHP and ethanol yielded extremely rapid inactivation 30 both on N95 and on stainless steel ( Figure 1A). UV inactivated SARS-CoV-2 rapidly from steel but more 31 slowly on N95 fabric, likely due its porous nature. Heat caused more rapid inactivation on N95 than on 32 steel; inactivation rates on N95 were comparable to UV. 33 34 for use under a CC0 license.Quantitative fit tests showed that the filtration performance of the N95 respirator was not markedly 35 reduced after a single decontamination for any of the four decontamination methods ( Figure 1B). 36Subsequent rounds of decontamination caused sharp drops in filtration performance of the ethanol-treated 37 masks, and to a slightly lesser degree, the heat-treated masks. The VHP and UV treated masks retained 38 comparable filtration performance to the control group after two rounds of decontamination, and 39 maintained acceptable performance after three rounds. 41Taken together, our findings show that VHP treatment exhibits the best combination of rapid inactivation 42 of SARS-CoV-2 and preservation of N95 respirator integrity, under the experimental conditions used here 43 (...

Diet modulates immune functions in different ways and affects host resistance to infections. In addition to the essential nutrients in food, nonessential food constituents such as nondigestible carbohydrates also affect the immune system. First results from human intervention studies suggest that the intake of inulin (IN) and oligofructose (OF) has beneficial effects on the gut-associated lymphoid tissue. At the level of the systemic immune system, however, only minor effects have been observed in healthy adult human subjects. In contrast, data from studies with infants suggest that supplementation with a prebiotic mixture positively affects postnatal immune development and increases fecal secretory IgA. Animal studies confirm the observations from human trials and give more insight into the immune tissue- specific effects of IN/OF. A clear outcome of the animal studies is that the intestinal immune system and especially the immune cells associated with the Peyer's patches are responsive to a dietary supplement of IN/OF and/or their metabolites. The mechanisms of IN/OF include indirect effects such as a shift in the composition of the intestinal flora and the enhanced production of immunoregulatory SCFA and perhaps other bacterial metabolites. Few data suggest direct effects of IN/OF via carbohydrate receptors on intestinal epithelial cells and immune cells. In conclusion, prebiotic IN/OF clearly modulate immunological processes at the level of the gut-associated lymphoid tissue, which may be associated with significant health benefits in infants and patients with intestinal inflammatory diseases.

The unprecedented pandemic of SARS-CoV-2 has created worldwide shortages of personal protective equipment, in particular respiratory protection such as N95 respirators. SARS-CoV-2 transmission is frequently occurring in hospital settings, with numerous reported cases of nosocomial transmission highlighting the vulnerability of healthcare workers. In general, N95 respirators are designed for single use prior to disposal. Several groups have addressed the potential for re-use of N95 respirators from a mechanical or from a decontamination perspective. Here, we analyzed four different decontamination methods – UV radiation (260 – 285 nm), 70ºC heat, 70% ethanol and vaporized hydrogen peroxide (VHP) – for their ability to reduce contamination with infectious SARS-CoV-2 and their effect on N95 respirator function.

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