This post covers the changes I’ve made to the N95 vs FFP3 & FFP2 masks article over time.

May 22, 2020 – Updated:

  • Added section and research on indoor vs outdoor spread.

May 13, 2020 – Updated:

  • Added section on selenium

May 12, 2020 – Updated:

  • Added section on shaving when using disposable respirators
  • Updated Vitamin D section to include the 2 latest studies on Covid-19 and vitamin D status – including listing what are considered normal, insufficient and deficient blood levels of 25(OH)D in those studies.
  • Add list from European Safety Federation of fake/suspicious PPE certificates.

Posted by John

Note: Not a Medical Doctor or PhD. I'm a researcher and writer, with a focus on the subjects of health and longevity. My intent is to write about scientific research in an accessible, understandable way. If you believe something I've stated needs a reference, and I haven't done so, please let me know in the comments. Follow on: Twitter

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    Excellent work – thanks so much for this!


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    So very helpful. Thank you very much! Cleared up confusion on masks and respirators. Also going to increase my selenium intake and get D3 supplements to beef up immune system!


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    thank you 🙂