Update per CDC:3-11-20...Persistence of Coronavirus on Inanimate Surfaces and its Effective Treatment

According to the CDC, COVID-19 is likely to remain infectious on surfaces for approximately 1 week. That timing varies for different types of surface materials. Measurable moisture droplets are emitted from our mouths by simple talking and open mouth breathing in addition to coughing and sneezing. This virus only has cell receptors for lung cells (it only infects your lungs). The only way for the virus to infect you is through your nose or mouth via your hands or an infected laugh, cough or sneeze onto or into your nose or mouth.

Open Mouth Heavy Breathing and Talking: Saliva Spray travels as much as 2-3 feet before dropping on surfaces.

Coughing: Saliva Spray travels approx. 4-6 feet

Sneezing: Air and moisture droplets exit at approx. 200 mph and travel as much as 10-15 ft., emitting approx. 1,400,000 moisture particles into the air & on surfaces.

The transmission or transportation routes of coronavirus include two forms:

1. Direct Transmission
2. Indirect Transmission

Direct Transmission occurs person-to-person, when one receives exhaled respiratory droplets in the air, from another’s breathing, talking, laughing, coughing and sneezing.

Indirect Transmission occurs with the touch or contact of any surface contaminated with an infected person’s respiratory droplets. When we touch an infected object and then re-touch our own nose or mouth we can be infected.

There is a wide variation in survival times for coronaviruses on different surfaces: metals, plastics, ceramic, formica, glass, wood, woven and non-woven fabrics, paper (including money, magazine pages). The smoother the surface the shorter the survival time. Temperature and relative humidity affect survival times as well, with cooler temperatures and higher levels of humidity providing the more optimal conditions for survival.

Fortunately, all contaminated surfaces can be effectively made safe by “correct” surface cleaning and disinfection procedures, and laundering practices. Facilities personnel should use EPA-registered disinfectants labeled to be effective against the pathogens, i.e.coronaviruses that are targeted for elimination. Follow manufacturer’s recommendations for use – dilution (i.e., concentration), contact or dwell time, and care in handling.

Infected surfaces should be treated with a two-step process involving cleaning, followed by disinfection.

The distinction is as follows:

1. Cleaning: The physical removal of soil, organic debris and particulate from surfaces.
2. Disinfection: The application of a chemical onto a surface to kill or inhibit microorganisms. It eliminates virtually all recognized pathogenic micro-organisms but not necessarily all microbial forms (e.g., bacterial spores) on inanimate objects. *Critical- Many disinfectants take 5 minutes to kill coronavirus on surfaces. Each brand has its own test data, which must be followed!

The Center for Disease Control (CDC) warns that all cleaning personnel treating suspected contaminated surfaces should wear proper Personal Protective Equipment (PPE): Goggles, N95 Respirator or better, and nitrile or latex gloves. All fabrics should be laundered in Hot Water and dried in a clothes dryer to fully rid them of the coronavirus.

Airborne “droplet nuclei” develop when the fluid of pathogenic moisture droplets from an infected person (1-5 microns) evaporates. (1 micron= one-thousandth of a millimeter). They are so small and light they may remain suspended in the air long after droplets have succumbed to gravitational forces and fallen on surfaces.

A recent edition of Nature Magazine reports that, “Since December 2019, the newly discovered coronavirus (Covid-19) has caused the outbreak of pneumonia in Wuhan and throughout China. Covid-19 enters host cells through human cell receptor ACE2, the same with SARS-CoV, but with higher binding affinity. The rapidly increasing number of cases and evidence of human-to-human transmission suggested that the virus was more contagious than SARS-CoV and MERS-Co.”

The science of cleaning and disinfection is clear and must be trusted and followed. Many, many lives depend on it.

Ian M Wallis

Wallis & Associates

Contamination Control Scientist wallisassociates.orghttps://www.linkedin.com/in/ian-wallis-6a0b9118/ 978-270-9882