The Science of COVID-19

Advocacy News
March 26, 2020
By Chuck White, Vice President of Regulatory Affairs

It seems that today it’s Coronavirus all day, every day, and that has been particularly true at PHCC. Just to add some fact to the issue, here are some science elements from a DHS Master Question List, plus others to consider.

The Wuhan novel coronavirus is called SARS-CoV-2; the disease it causes is called COVID-19. SARS is an acronym for severe acute respiratory syndrome, and there are many variants of the SARS virus.

Could We Stop Spitting Please?

SARS-CoV-2 is consistently present in infected patient saliva and mucous membranes. It can persist on plastic and stainless steel surfaces up to 3 days (at 21 – 23 degrees C, 40% RH) with a half-life of 13 to 16 hours. SARS-CoV-2 has an aerosol half-life of 2.7 hours. Studies suggest that other coronaviruses can survive on non-porous surfaces up to 9 to 10 days and porous surfaces for up to 3 to 5 days in air-conditioned environments (20 to 25 degree C, 0 to 50% RH). SARS can persist with trace infectivity for up to 28 days at refrigerated temperatures (4 degrees C) on surfaces.

Watch Out When Drain Cleaning!

SARS-CoV-2 has been isolated from human feces. Coronavirus may be resistant to thermal inactivation for up to 7 days when stabilized in stool.

Wear a Mask!

PPE effectiveness for SARS-CoV-2 is currently unknown, but using comparable information from SARS yields the best suggested practice. The use of face masks is not recommended for healthy people unless they are in close contact with infected people. Standard precautions for entering rooms where close contact may happen should include eye protection, a face shield, gloves, long sleeve gowns and respirators (Certified NIOSH N95 is acceptable). Porous hospital materials including paper and cotton cloth maintain SARS-CoV (not -2 as that is of unknown certainty) for a shorter time than non-porous materials. 

Filtration Questions Abound!

NIOSH N95 masks are an acceptable protection. N95 masks are rated to capture 95% of NaCl particles 0.3 microns in diameter per CDC. HEPA filters capture 99.97% of particles 0.3 microns in diameter per EPA ratings. The size of the Most Penetrating Particle (MPP) is used in rating these products. In general, SARS-CoVs have a particle diameter of 0.12 microns per the National Library of Medicine. Those sizes do not seem to indicate an acceptable use of N95 masks but, in reality, the percentage of capture does not go down significantly, and, most importantly, the virus is typically attached to other material in droplet form making a much larger particle in the range of 5 microns. Caution should be used for masks with exhale valves; contaminated air may be exhausted to the surrounding room air or occupants.

Disinfect Surfaces Often!

No decontamination data for SARS-CoV-2 have been identified. EPA has released a list of disinfectants, but solutions were not tested on live viruses. The list includes brand names and directions for usage.

Vice President of Regulatory Affairs
, PHCC-National Association
Charles “Chuck” R. White serves as Vice President of Regulatory Affairs for PHCC—National Association. White works closely with government regulatory bodies, such as the DOE, and serves on a number of councils and coalitions including NSPC, PERC, ABPA and IAPMO as a representative of PHCC’s contractors.

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