Effect of portable HEPA filters on COVID-19 period prevalence: an observational quasi-interventional study in German kindergartens User AndrewHeard, in the LockdownSkepticism subreddit, 25 Jan 2024
Effect of portable HEPA filters on COVID-19 period prevalence: an observational quasi-interventional study in German kindergartens User open_reading_frame, in the Novel Coronavirus (COVID-19) subreddit, 22 Nov 2023