> What is PMMoV normalization?
> In addition to the pathogens it tests for, WastewaterSCAN measures an extremely common, harmless plant virus that is consumed when people eat. It is called pepper mild mottle virus (or PMMoV). By measuring the concentration of PMMoV genetic markers per dry weight gram of wastewater solids, WastewaterSCAN can account for how much viral material is recovered from each sample and changes to the “fecal strength” of that sample. For example, heavy rain that drains into a wastewater system can dilute the strength of a particular day’s sample.
OK, that's pretty clever and it sounds useful, so I guess I should turn on that toggle. But then I read further and see this:
> Our analysis suggests that both the concentrations of the SARS-CoV-2 genes measured as copies per gram of solid waste and those concentrations normalized by PMMoV are proportional to laboratory confirmed COVID-19 incidence rates in the sewersheds.
How can both things be proportional? Do they actually mean positively correlated?
If raw data is already proportional to lab tests, then it doesn't seem like there's any benefit from normalizing.
The post holiday gathering spike is rather obvious. Not just for COVID but for everything. We really should have test kits, and people should test BEFORE travel. A national level policy of full refunds if tested positive (for any illness / disease) could help prevent the needless spread of illness.
Wastewater surveillance is a pretty crazy technology. My neighbor works on projects using it for wildlife tracking, and they can get startling amounts of information about what is going on in a given watershed. What (e.g endangered) animals are present, what animals humans are eating, etc. And all the way down to the viral level, obviously.
See also: https://biobot.io/data/
It's Suspect that adjacent cities have such divergent trends. For example Novato vs San Rafael CA.
Novato: http://publichealth.verily.com/#Novato,%20CA:SARS-CoV-2
San Rafael: http://publichealth.verily.com/#San%20Rafael,%20CA:SARS-CoV-...
I remember during the tail end of the pandemic someone posted a link to a big spike in wastewater COVID testing in our city's sewers. So I decided to pay close attention to the COVID test rates/hospitalizations for the next 2 months. But I never ended up seeing any correlation. The trendline stayed stagnant, before declining as it did everywhere else.
I know that's a one-off non-scientific example, but it made me wonder if it's occasionally just noise in a small sample set? Certainly useful but maybe not always easy to translate/project into IRL illness rates.
Lots of cities missing from this, many exist but lack any data
Not sure how helpful this is when huge swathes of the population aren’t represented here
Santa Clara has data for the south bay, and I couldn't find it on the verily page.
wastewater seems like such an incredible resource for monitoring so many things. its such a huge statistical sample, for free
The longer a society wears masks, the sicker everyone will be when they eventually come off. In the formerly overly cautious US Northeast, kids are getting sick left and right this school year. And COVID is the least dangerous bold-faced name they need to worry about.
It seems that we are perpetually on the verge of the next big wave, the next scary variant. I am always told by administrators that cases are rising even though I am having trouble finding patients on the floor with covid.
I am continually surprised at how many people don’t wear masks at places like the grocery store even as cases are rising. I got covid over the summer and it was horrible! I lost two weeks of work which was a lot of money to lose, missed multiple dates with my partner I would have really enjoyed and felt totally isolated. Then I felt fatigue and brain fog for months afterwards. Afterwards I got the bivalent vaccine so I do feel more protected now, but there’s still a risk.
Wear a mask and wash your hands folks!