RESUMO
Wearing respirators and face masks is effective for protecting the public from COVID-19 infection. Thus, there is a need to evaluate the performance of the commonly used respirators and face masks. Two experimental systems were developed to investigate seven different mask materials, which have a fiber size range from 0.1 µm (100 nm) to 20 µm (20,000 nm). One of the systems is a computer-controlled setup for measuring the filtration performance, including size-dependent filtration efficiency and pressure drop, while the other system is for testing the fiber shedding behavior of the materials. The technique of scanning electron microscope (SEM) was applied to observe the dimensions and structures of those materials, which are made of nonwoven-fabrics electret-treated media, cotton woven fabrics, or nanofiber media. The study indicated that the 3M N95 respirator has the best overall filtration performance with over 95% efficiency and low pressure drop of 74.1 Pa. The two commercial cotton face masks have the worst filtration performance in general, with a filtration efficiency of around 25%. No broken fibers from by the seven tested respirator and face mask materials were discovered;however, dendrite structures likely shed by the SHEMA97 face mask with a size comparable to its nanoscale fibers were identified. The reason for this phenomena is presented. © 2023, AAGR Aerosol and Air Quality Research. All rights reserved.
RESUMO
Objectives: To investigate the risk of flare-ups after COVID-19 vaccination in patients with rheumatic disease. Method(s): A total of 1,617 patients with rheumatic diseases were identified from three rheumatology clinics. Patients were interviewed for demographic data, disease activity, and vaccination status. Disease flare-up was determined clinically by independent rheumatologists. Change of serum markers and medications were retrieved from medical records. The risk of exacerbation of rheumatic disease, change in serum markers, and escalation of rheumatic medications between vaccinated and nonvaccinated patients were determined using Cox, linear, and logistic regression models, respectively. Possible confounding factors were also taken into consideration. Result(s): Among 562 (34.76%) patients who received COVID-19 vaccination, rheumatic disease (HR = 2.10, P < 0.001), inflammatory arthritis (HR = 2.71, P < 0.001), rheumatoid arthritis (RA) (HR = 2.03, P = 0.002), spondyloarthritis (SpA) (HR = 4.78, P < 0.001), autoimmune disease (HR = 1.77, P = 0.01), and systemic lupus erythematosus (SLE) (HR = 1.99, P = 0.02) were associated with postvaccination clinical flare-up. Adult Still's disease (B = 12.76, P = 0.03) was associated with increased serum C-reactive protein (CRP). No association was found between vaccination and escalation of rheumatic medication. Subgroup analyses showed that only the mRNA vaccine was associated with flare-ups. Conclusion(s): COVID-19 vaccination was associated with minor disease flare-up but not escalation of rheumatic medications. In the absence of absolute contraindications, COVID-19 vaccination is recommended in patients with rheumatic disease. KEY MESSAGES 1. Vaccination is effective in the prevention of morbidity due to COVID-19 in patients with autoimmune diseases. 2. The mRNA vaccine was associated with mild rheumatic disease flare-up. 3. Inactivated virus vaccine is preferable to mRNA vaccine in patients with active autoimmune disease. Copyright © 2023 The Author(s).