It is known that COVID-19 spreads through droplet transmission.  Centers for Disease Control indicates early reports suggest person-to-person transmission most commonly happens during close exposure to a person infected with   COVID-19, primarily via respiratory droplets produced when the infected person coughs, sneezes, or talks. Droplets can land in the mouths, noses, or eyes of people who are nearby or possibly be inhaled into the lungs of those within close proximity. Evidence also suggests that people who are infected, but remain asymptomatic play a role in the spread of COVID-19.

Droplets are heavy, think of a wet cough, typically the heavy particle will not carry far.  The droplets which are generated by a patient who is coughing, sneezing, or talking can land on surfaces and you can also contaminate yourself by touching the surface followed by touching your face.

Patients in droplet isolation require healthcare workers to wear surgical mask, gloves, and gown.  During times when available PPE is limited, it is recommended, if possible, to cohort COVID positive patients, one measure to preserve limited PPE.  Other diseases that require droplet precautions include seasonal flu, bacterial meningitis, and pertussis.

There is much discussion about COVID-19 also having properties which require airborne precautions due to aerosolized particles.  An aerosol, which are micro-droplets, weigh much less, these may stay suspended in the air for longer period of time or even have the ability to travel by air currents.  These small droplets are produced during normal breathing. Evidence also suggests that people who are infected, but remain asymptomatic play a role in the spread of COVID-19.   In addition, certain medical procedures, such as collecting respiratory specimens are considered aerosol generating procedures and would require airborne precautions.

When airborne transmission is known, the isolation protocols are stricter. Precautions include wearing an N95 or higher level respirator, eye covering, gloves, and gown, and if possible, isolating the patient in a negative pressure airborne infection isolation room. Other diseases requiring airborne precautions include measles, chickenpox, and TB.

The attached picture are the recommendations for COVID.  When N95 masks are in limited supply, they should be reserved for use when known aerosolized generating procedures will be performed.


Author: Lisa Chadwick, RN, MS, Director of Safety and Risk Management, Privacy Officer