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I don't know. I am assuming that the baseline will be comfortably above "1" that they can account for the occasional month where SARS-CoV-2 is circulating less than "normal"

This does not reflect what I am reading on the CDC website. They say they are normalizing to the 10th percentile of the previous year, which is very different from what you describe. Can you point me to where you are getting your understanding?

And can you clarify what you mean by "value of the previous year"? Do you mean the median? Single day median from one year ago, or annual median from the previous 12 months? Something else?

This is what they say: "The 'baseline' is the 10th percentile of the log-transformed and normalized concentration data within a specific time frame... baselines are re-calculated every six calendar months (January 1st and July 1st) using the past 12 months of data."

Log transformation of the SARS-CoV-2 concentration data should produce a normal distribution (bell curve) & the selection of the 10th percentile of that bell curve should produce a baseline representing the lowest 10% values of the last 12 months of observation If I understand what they are saying

My read* on this is that the CDC reporting of WVAL was always reported as SD relative to a baseline, (rather than absolute values). Up until Dec. '24 was this baseline simply zero, or calculated with a different method than now? *backed by a minimal exposure to post-secondary stats decades ago

yes, that's my impression too. they'd need a recent baseline to do the calculation they're doing now, so i doubt it's zero. did they shorten the baseline period for covid because it's not seasonal like flu/rsv? flu/rsv is 18 months, maybe a short period for covid is a good thing bc mult waves/yr?🤔

What this means is that the level of SARS-CoV-2 virus circulating in the environment will be reported as the difference between current readings & the readings of a year ago If January of 2024 the reading was 1,000 and in January 2025 it's also 1,000, wastewater levels will be reported as 0 (zero)

wait, this sounds very different from normalizing to an endemic _baseline_. I would have interpreted "endemic baseline" as meaning the minimum levels observed during endemic spread. I can't find a description of this CDC policy change online -- do you have a link to it to help clarify?

It is difficult to fathom just how cynical this is It's a bureaucratic admission that not only do we need to live with a constant and very high amount of SARS-CoV-2 virus around us but that this constant and very high amount will represent "normal."

The first chart here are SARS-CoV-2 wastewater levels from 2022 to present prior to baseline normalization The second chart is the same thing but just for 2024 The third is a (predicted) chart for 2025 assuming wastewater levels in 2025 are similar to 2024 Much less scary, eh? That's the intent

If we don't need to live with a constant amount of SARS-CoV-2 virus in the air we breathe... ...then why do we live with a constant amount of SARS-CoV-2 virus in the air we breathe?

there was a time when we could ask our "representatives" to do something about it and they would. now? they're too busy fundraising and funneling their bribes to give a shit about the "little folk".