Thanks so much for the kind feedback and comparison calculation! Your skepticism about the eACH estimates is warranted—I was unaware that coronaviruses were unusually susceptible (compared with other viruses, you mean?); the estimates we saw were all based on either SARS-CoV-2 or tuberculosis (also quite susceptible). It’s useful to know how other people are approaching this question, and ultimately the problem calls for much more extensive real-world observations.
Yea, the way I recall it is that coronaviruses are more susceptible than other viruses. I first tried to recheck this in Appendix B of Kowalski (2009), but the values provided there vary extremely widely. I suspect the experimental quality varies a lot between those estimates, and coronaviruses were, of course, of much less interest back then.
[...]
IMO, the easiest way to read these values is the D90 (J/m^2) value, the dose required to inactivate 90% of viruses in a sample. This is equivalent to speaking about a “1 log reduction”.
Blatchley et al. (2022) have more recent data and provide better evidence for coronaviruses being especially susceptible:
“At 254 nm approximately 1 log10 reduction of coronaviruses is achieved for each 2 mJ/cm2 delivered UV-C fluence (dose). For comparison, other human pathogenic viruses, such as poliovirus and rotavirus require about 4–5 times that amount (i.e., 8–10 mJ/cm2) for each log10 unit reduction (Masjoudi et al., Citation2021).
UV222 irradiation is at least as effective as UV254 irradiation for inactivation of viruses, with approximately 1 log10 reduction of coronaviruses achieved for each 1 mJ/cm2 of delivered UV-C fluence or less. In other words, irradiation at 222 nm provides roughly twice the rate of inactivation as observed at 254 nm.”
On the other hand, when considering catastrophic biorisk, we mostly don’t care about, e.g., poliovirus, but other viruses with more pandemic potential, such as Influenza. So the more productive comparison could be restricted to these high-profile pathogens. I haven’t taken the time to compare all their UV susceptibility values. If they turn out to be similar to those of coronaviruses, my skepticism of high eACH estimates might not be as valid.
Thanks so much for the kind feedback and comparison calculation! Your skepticism about the eACH estimates is warranted—I was unaware that coronaviruses were unusually susceptible (compared with other viruses, you mean?); the estimates we saw were all based on either SARS-CoV-2 or tuberculosis (also quite susceptible). It’s useful to know how other people are approaching this question, and ultimately the problem calls for much more extensive real-world observations.
Yea, the way I recall it is that coronaviruses are more susceptible than other viruses. I first tried to recheck this in Appendix B of Kowalski (2009), but the values provided there vary extremely widely. I suspect the experimental quality varies a lot between those estimates, and coronaviruses were, of course, of much less interest back then.
[...]
IMO, the easiest way to read these values is the D90 (J/m^2) value, the dose required to inactivate 90% of viruses in a sample. This is equivalent to speaking about a “1 log reduction”.
Blatchley et al. (2022) have more recent data and provide better evidence for coronaviruses being especially susceptible:
“At 254 nm approximately 1 log10 reduction of coronaviruses is achieved for each 2 mJ/cm2 delivered UV-C fluence (dose). For comparison, other human pathogenic viruses, such as poliovirus and rotavirus require about 4–5 times that amount (i.e., 8–10 mJ/cm2) for each log10 unit reduction (Masjoudi et al., Citation2021).
UV222 irradiation is at least as effective as UV254 irradiation for inactivation of viruses, with approximately 1 log10 reduction of coronaviruses achieved for each 1 mJ/cm2 of delivered UV-C fluence or less. In other words, irradiation at 222 nm provides roughly twice the rate of inactivation as observed at 254 nm.”
On the other hand, when considering catastrophic biorisk, we mostly don’t care about, e.g., poliovirus, but other viruses with more pandemic potential, such as Influenza. So the more productive comparison could be restricted to these high-profile pathogens. I haven’t taken the time to compare all their UV susceptibility values. If they turn out to be similar to those of coronaviruses, my skepticism of high eACH estimates might not be as valid.