SARS-CoV-2 is viable for several days after being deposited on both nonporous surfaces (e.g. stainless steel, plastic) and more than 24 h on porous surfaces (e.g. cloth). Recently, there has been increased interest for products that are continuously active and can provide efficacy in between regular cleaning and disinfection. Previously, we have developed an N-halamine-based polymer coating that provides long-lasting disinfection efficacy through extending the shelf-life of chlorine on surface. This current effort focused on determining whether HaloFilm can extend the efficacy of chlorine for enabling residual decontamination efficacy on both non-porous and porous surfaces against an isolate of SARS-CoV-2 (USA-WA1/2020) over time. For the non-porous surface, the time-course study showed that increased exposure time with the coated-treated stainless steel resulted in significant improvement of log reduction compared to coupons treated with household bleach alone (Figure A). A log reduction of 2.25 was observed when the virus was in contact with the coated-treated stainless steel surface for 2 hours and the 8-hour time-point resulted in complete inactivation within the detection limit (&gt;3.63 log reduction). For the porous surface, uncoated fabric resulted in 5.95 mean log recovery of viruses while the HaloFilm-coated, chlorinated fabric only recovered &lt; 1.59 mean log of viruses (detection limit 1.42 log), which is &gt; 4.36 mean log reduction in 2 hours (Figure B). We further simulated the decay rates of SARS-CoV-2 on the HaloFilm-coated stainless-steel surface using a Bayesian regression model and found a median estimated half-life of just short of 14 minutes (Figure C&D). This study reports the best-known efficacy data against SARS-CoV-2 within the category of residual antimicrobial coating products to date. This new technology, in concert with chlorine-based disinfectant products (e.g. household bleach), can be adopted as an immediate and cost-effective strategy for mitigating the transmission of SARS-CoV-2 from all types of surfaces.

Rapid inactivation of SARS-CoV-2 on surfaces treated with N-halamine chlorine-extending polymer coating

ACS Fall 2021

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