What does "....10000 units per 15 min (quick reduction)" mean?

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Discussion Overview

The discussion revolves around the interpretation of the term "10000 units per 15 min (quick reduction)" as used by the WHO in the context of using heat to inactivate a virus. Participants explore the implications of this measurement and its relevance to viral inactivation processes.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant seeks clarification on the meaning of "10000 units per 15 min" in relation to heat treatment for virus inactivation.
  • Several participants request a source link to better understand the context of the quoted term.
  • A participant provides a source link and explains that the term refers to "10 000 infectious virus units in 15 min," indicating that heating a solution at 56°C for 15 min resulted in no infectious viruses remaining.
  • Another participant suggests that the "10000 units" might represent a logarithmic scale reduction, proposing that a reduction of 10000 units corresponds to a 10^4 reduction in the number of viruses.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the interpretation of the term "10000 units." While some agree on the explanation provided regarding viral inactivation, others propose alternative interpretations related to logarithmic scaling.

Contextual Notes

The discussion includes varying interpretations of the term and its implications, with some assumptions about the nature of the data and the methods used for measuring viral inactivation remaining unaddressed.

mesa
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Hello, looking to find out what the term "10000 units per 15 min (quick reduction)" from the WHO means in terms of using heat to kill a virus.
 
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It would help if you post a link to the source where the info comes from so that we can see the context of the quote.
 
mesa said:
Sure thing:

https://www.who.int/csr/sars/survival_2003_05_04/en/

Thanks. Later in the document, they clarify that the amount refers to "10 000 infectious virus units in 15 min." So basically, they had a solution of the virus containing 10,000 infectious viruses, heated it at 56°C for 15 min, and found no infectious viruses remaining after heat treatment (meaning the heat had inactivated all of the viruses in solution).

One can measure the number of infectious viruses in a solution by applying that solution to a plate of cultured cells, and measuring the number of cells that become infected (a process called viral titering).
 
I would tend to think that the 10000 units refers to a plotting of before and after on a logarithmic scale, base 10, since if the studies are dealing with a large number of items ( viruses in this case ) before the application of the treatment to the much smaller number if items after the treatment.
In other words a 10000 unit reduction is a 104 reduction of the items in the original sample.
 

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