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Marc Johnson Profile
Marc Johnson

@SolidEvidence

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Molecular virologist, Professor, and wastewater detective. Same handle on bsky. Ignore the check, I'm doing an experiment.

Columbia, Mo.
Joined January 2022
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@SolidEvidence
Marc Johnson
8 months
Do you think you've had long-term GI problems since having Covid? .We are performing a study examining the characteristics of viruses, specifically persistent SARS-CoV-2 infections, in stool samples. 1/3.
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@SolidEvidence
Marc Johnson
3 days
Weird. I'm perplexed that some people actually argue that it is better to have less information. I don't agree with anti-vaxxers, but I at least understand their thought process. I just can't wrap my head around the idea that it is better to be less informed.
@SolidEvidence
Marc Johnson
4 days
I've always found this frustrating. You or your child has a respiratory infection. It's not flu or COVID. Your doctor can only tell you, 'you have a virus'. Could it be a little bit more specific?. We hope to help answer this question, non-invasively, and for free. 1/
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Marc Johnson
4 days
That's it for now. We continue to recruit more sewersheds in partnership with @SecureBio. More updates to come. 10/10.
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@SolidEvidence
Marc Johnson
4 days
This is fascinating. Although the rhinoviruses were usually surging in Spring, there was an outbreak of C42 in Fall of last year and it occurred in every one of the sewersheds coast-to-coast. Who knew?.9/
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Marc Johnson
4 days
And if you look at the other locations, most of the serotypes prevalent in Columbia this year were prevalent everywhere. 8/
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@SolidEvidence
Marc Johnson
4 days
The rhinoviruses have been most prevalent in late Spring, and most of the prevalent serotypes in Columbia last year are not prevalent this year. 7/
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Marc Johnson
4 days
In the legend you can toggle the different sewersheds we are reporting (hopefully adding more soon). 6/
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Marc Johnson
4 days
First, we only listed the serotypes that have appeared in at least 4 consecutive samples. They are ordered based on when they first appeared in 4 consecutive samples. Time goes left to right, starting in 2024. Larger circles mean more of that serotype detected. 5/
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@SolidEvidence
Marc Johnson
4 days
We debated how to best display this. There are over 100 rhinovirus serotypes, and we wanted to display their prevalence over space and time. Too many dimensions. This was our first stab at it. 4/
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Marc Johnson
4 days
As promised, we've now added a standalone readout of the rhinoviruses on our wastewater dashboard. 3/.
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Marc Johnson
4 days
Contrary to my prior assumptions, many of the most common pathogens are not everywhere, all the time. They occur in discrete waves, often nationwide. I wrote about this recently with Rhinoviruses, the most frequent cause of the common cold. 2/.
@SolidEvidence
Marc Johnson
14 days
This is cool. I was poking around at the Rhinovirus (common cold) data and realized that my perception about these viruses was completely wrong. 1/
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Marc Johnson
4 days
I've always found this frustrating. You or your child has a respiratory infection. It's not flu or COVID. Your doctor can only tell you, 'you have a virus'. Could it be a little bit more specific?. We hope to help answer this question, non-invasively, and for free. 1/
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@SolidEvidence
Marc Johnson
6 days
4 part. What movie featured this bridge?.Who directed?.What actor has been in the most films of that director?.What was that actor’s best film?
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Marc Johnson
6 days
Tougher one. Where am I?
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Marc Johnson
10 days
Where am I?
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@SolidEvidence
Marc Johnson
12 days
Where am I? Be precise.
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Marc Johnson
14 days
This probably isn’t a surprise to real epidemiologists, but it was a revelation to me. Anyway, I think we’re going to have to add a rhinovirus breakdown on our dashboard. 16/16.
@SolidEvidence
Marc Johnson
15 days
I’m thrilled to announce the update of our water surveillance dashboard. Many improvements, and our first substantial move into ‘OneHealth’. Read to the end to find the Easter Egg. 1/.
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@SolidEvidence
Marc Johnson
14 days
Presumably each season we get a little bit of herd immunity against the serotype that is surging, so it is outcompeted the next season by an antigenically distinct serotype. 15/.
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@SolidEvidence
Marc Johnson
14 days
This suggests that rhinoviruses really are more like influenza. It’s not a continuous swarm, but rather a bunch of discrete, nation-wide (world-wide?) surges of individual serotypes. 14/.
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Marc Johnson
14 days
More importantly, the serotypes surging in Columbia in 2025 appear to be surging everywhere. 13/
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Marc Johnson
14 days
Then I looked at the variation geographically. We weren’t sampling other sites in the 2024 season, but the serotypes that surged in Columbia in 2024 didn’t appear to surge anywhere in 2025. 12/
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