A quick guide to #PPE (personal protective equipment) for non-professionals. This is NOT medical advice.

PPE includes masks, face shields, hoods, respirators, gloves, etc. PPE is used to protect healthcare workers and patients from spreading and catching infectious diseases.
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METHODS OF DISEASE TRANSMISSION:
Different infectious diseases are transmitted in different ways:

* Direct Contact
* Indirect Contact (fomites)
* Fecal-oral Route
* Droplet Transmission
* Airborne (Aerosol) Transmission
* Vector-borne transmission (fleas, mosquitos, etc)
#PPE 2/

Methods of infectious disease transmission are NOT mutually exclusive.

Many diseases, like #SARS_COV_2, the virus causing #COVID19, spread by droplets, aerosols, indirect contact, and the fecal-oral route.

The difference between droplets & aerosols can be blurry in practice. 3/

In healthcare settings, workers require different combinations of #PPE depending on the specific infectious organism(s) (known or suspected), as well as the specific scenario or procedure.

Some procedures, like bronchoscopies, generate fine mists or aerosols by their nature. 4/

DIRECT CONTACT:
Direct contact refers to transmission of an infectious organism via skin-to-skin contact with an infected person. In a non-healthcare setting, it includes kissing or sexual intercourse.

Dangerous bacteria like MRSA, c. difficile, etc. can spread this way. 5/

INDIRECT CONTACT:

Indirect contact means transmission of an infectious organism by contact with a non-living object (a "fomite") like a doorknob, a bed or pillow, cups/dishes/silverware, a water fountain, children’s toys, a catheter, a pen, etc. 6/ https://www.nih.gov/news-events/news-releases/new-coronavirus-stable-hours-surfaces

The longer an organism survives on surfaces, the more transmissible it is.

Influenza survives up to 24-48 hours on hard, nonporous surfaces (and 8-12hr. on cloth, tissues, etc).

SARS-NCoV2 survives 72-96 hours on hard surfaces (we think).

Norwalk Virus survives for WEEKS! 7/

DROPLET TRANSMISSION

The flu, common cold, and SARS-CoV2 can be spread by droplets. When an infected person sneezes or coughs, infected droplets can fly through the air and land on someone or something nearby (usually within 6ft./2m).

Droplets can land in your eyes or mouth! 8/

AIRBORNE (AEROSOL) TRANSMISSION

Ever looked at a sunbeam shining in through the window? All those fine particles of dust floating around, never seeming to land? Those are aerosols.

Tuberculosis, chickenpox, measles (and we think SARS-CoV2) can survive in aerosols for hours. 9/

If an infectious organism has:

* an ability to survive for a long time in airborne (aerosol) form
* a high "infectivity" (ability to infect hosts)
* high "virulence" (ability to harm)

It's a BIG problem when that organism enters a population of hosts who share the same air. 10/

Without adequate #PPE, healthcare workers cannot protect their patients, themselves, and their own families from infection.

Dozens, perhaps over 100 doctors, nurses, & hospital staff have already died from #COVID19 worldwide. #GetMePPE OR #PPEShortage 11/ https://www.nytimes.com/2020/03/19/health/coronavirus-masks-shortage.html

TYPES OF #PPE: MASKS & RESPIRATORS

A "respirator" generally refers to a mask that seals tight to the face & provides protection from airborne diseases, whereas a "mask" might refer to a simple surgical mask with no seal.

A respirator requires skilled, careful fit-testing. 12/

#PPE: SURGICAL MASK
Basic design. Doesn’t form to face. Loops around ears

Uses:
* Keep internal droplets IN
* Keep external droplets OUT

Who wears:
* Infected people, to keep their coughs contained.
* Workers in lower-risk exposure situations (check-in desk, unit secretary) 13/

#PPE: N95 MASK, NO VALVE
Airtight with proper fit. Comes in regular, small, and duckbill

Uses:
Keeps 95% of airborne particles out
Keeps external droplets out
Keeps internal droplets and air in

Who wears:
Healthcare workers involved in direct patient care (aerosols or not). 14/

#PPE: N95 MASK W/ VALVE
Keeps 95% of airborne out; has unfiltered 1-way exhaust valve (wildfire & construction)

Uses:
* Keeps external droplets & airborne particles out
* Doesn’t keep ANYTHING in
* Protects wearer; nobody else

Who wears:
* Healthcare worker who is NOT sick
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#PPE: FACE SHIELD
Protects wearer from fluids landing in eyes or face.

Certain procedures, as well as coughing, sneezing, or talking propel droplets.

Face shields are meant to be used with a mask & goggles. Face shield also extends the life of a mask by protecting its surface.

Face shields are generally not used alone, but in conjunction with other PPE and are therefore classified as "adjunctive personal protective equipment".

Healthcare workers use face shields, combined with N95 respirators, in droplet (not aerosol) precaution zones and common areas

Don't assume that droplets and aerosols can't coexist. If there's droplets there may be aerosols, even up close.

Face shields provided a 96% reduction in risk of inhalational exposure from influenza (aerosol diameter 8.5 μm) at a distance of 18 in.(46cm). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4734356/

A face shield provides some temporary protection from close-up aerosols, but the adjunct protective effect lessens the farther away and more diffuse the aerosol is.

A face shield with an N95 mask is no substitute for a PAPR (power, air-purifying respirator - pronounced "papper")

Safety note: when you take off your mask, take it off from the straps, not from the mask.

DO NOT TOUCH YOUR MASK. Not ever. Not when you're wearing it. Not when you take it off.

The outside of the mask is loaded with virus and bacteria. That's its job. @SCMPNews video explains: