Here's a study using a different coronavirus.

Brasses containing at least 70% copper were very effective at inactivating HuCoV-229E (Fig. 2A), and the rate of inactivation was directly proportional to the percentage of copper. Approximately 103 PFU in a simulated wet-droplet contamination (20 µl per cm2) was inactivated in less than 60 min. Analysis of the early contact time points revealed a lag in inactivation of approximately 10 min followed by very rapid loss of infectivity (Fig. 2B).

5Nick_Tarleton4moOn the other hand: [https://www.medrxiv.org/content/10.1101/2020.03.09.20033217v1]

Extract from that paper

SurfacesHCOV19Survival

HCOV-19 is a (unusual?) name for the nCOV/SARS-CoV-2 virus responsible for COVID19. It's the one in red.

[ Question ]

How long does SARS-CoV-2 survive on copper surfaces

by ChristianKl 1 min read7th Mar 202015 comments

25


I wrapped copper tape around a wood stick:



I will use this stick to push any buttons in public and press door handles. How reasonable is it to touch the copper-coated stick after it touching potentially contaminated surfaces? Do I have to pay attention to not touch the stick at places where it touches other surfaces?

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6 Answers

Here's a study using a different coronavirus.

Brasses containing at least 70% copper were very effective at inactivating HuCoV-229E (Fig. 2A), and the rate of inactivation was directly proportional to the percentage of copper. Approximately 103 PFU in a simulated wet-droplet contamination (20 µl per cm2) was inactivated in less than 60 min. Analysis of the early contact time points revealed a lag in inactivation of approximately 10 min followed by very rapid loss of infectivity (Fig. 2B).

From the Justified Advice Thread Summary

An important update for me was that the halflife on copper is ~3.5 hours, which means that it's actually quite awhile before copper will kill coronavirus thoroughly enough to be "safe". I think it's more useful as something that "becomes clean overnight" than something like "you can reliably use a copper thing without having to clean it."

This was the clear winner of JPA Olympics– it’s cheap, effective, and very few people had heard of it before. In fact we were hoping for a highly polished, intensely researched post on just this; unfortunately no one has the time right now.

In its place, please enjoy these links:

  • This pre-print showed that this coronavirus in particular had a half life of 2.4-5.11 hours on copper, in contrast to 10.5-16.1 on steel or 13-19.2 on plastic
  • This review showed H1N1 decreased by 4 logs (a factor of 10^4) in 6 hours;
  • This study showed vaccinia and monkeypox viruses reduced by 6 logs (a factor of 10^6) in 3 minutes
  • This study showed murine norovirus was destroyed in 30 minutes, though it doesn't work very well at 4C;
  • This review says that copper oxide filters neutralize all of "bacteriophages [58-62], Infectious Bronchitis Virus [63], Poliovirus [61,64], Junin Virus [59], Herpes Simplex Virus [58,59], Human Immunodeficiency Virus Type 1 (HIV-1) [11,65-67], West Nile Virus [11], Coxsackie Virus Types B2 & B4, Echovirus 4 and Simian Rotavirus SA11 [68]. More recently, the inactivation of Influenza A [55,65], Rhinovirus 2, Yellow Fever, Measles, Respiratory Syncytial Virus, Parainfluenza 3, Punta Toro, Pichinde, Adenovirus Type 1, Cytomegalovirus, and Vaccinia [65]".

The basic answer is - pretty fast, but not immediately.

This paper compares 9 metals (lead kills slightly better than copper but that unfortunately extends to the humans; zinc and some other metals also kill pretty well, only two did not). Within an hour, copper dropped CFU from 10^6->10^1 (the measurement threshold). Zinc took 2 hours, nickel 4.

(this research actually done by Connor Flexman)

Your stick would be significantly better if you used a uniform cylinder, rather than a piece of natural wood. The uneven shape means that the copper tape has a lot of crevasses, which can get dirt in them that's hard to clean out. If the copper has dirt on top of it, it's not going to inactivate anything that's on top of the dirt.

Disclaimer: I'm not an expert.

It seems to me that this preprint suggests that in certain conditions the half-life of HCoV-19 (SARS-CoV-2) is ~0.4 hours on copper, ~3.5 hours on cardboard, ~5.5 hours on steel, and ~7 hours on plastic.