Share this page!

Enter URL or ID to Unroll

You can paste full URL like: https://x.com/threadreaderapp/status/1644127596119195649
or just the ID like: 1644127596119195649

How to get URL link on X (Twitter) App

  1. On the Twitter thread, click on or icon on the bottom
  2. Click again on or Share Via icon
  3. Click on Copy Link to Tweet
  4. Paste it above and click "Unroll Thread"!
  5. More info at Twitter Help
Mike Hoerger, PhD MSCR MBA Profile picture
@michael_hoerger
Jul 14, 2022 • 10 tweets • 10 min read • Read on X
Kids <2 yrs old can’t mask.
Kids <6 months can’t vax.

Many parents are using strollers w/rain covers to try to get some protection during essential activities.

Does adding a #PAPR or #HEPA device help?

I tried 6 models: engrxiv.org/preprint/view/…

#PAPRbuggy #HEPAbuggy
1/10 Image
First off, thanks @RealSexyCyborg for the original design. Thanks to @ccwake1, @gjmf, @drgregkelly for ideas too. Happy to acknowledge!

My goal was to test 6 models & help relate them to non-engineers.

2/10

The PAPR & HEPA buggies I tested had an estimated 57-951 air changes per hour (ACH) in these TINY spaces. The worst design had about 3x the air cleaning of an OR.

You can make a #PAPRbuggy that’s super discrete for about $110 more than an existing stroller & rain cover.

3/10 Image
With even a cheapo ($55) HEPA, you can make a relatively discrete #HEPAbuggy w/good air cleaning (see Figure A1.5 in preprint).

BUT, I also tested some power models. This one runs at an estimated 900+ ACH, or about 60x the minimum rate of an OR. 😎 Vroom vroom.

4/10
Want to learn more about a #PAPRbuggy or #HEPAbuggy?

See the preprint:
🔸 Figure A1: Design ideas
🔸 Tables 1 & A4: Estimated specs
🔸 Table A3: Parts & supplies w/links
🔸 Tables A1-A2: Help w/any calculations

engrxiv.org/preprint/view/…

5/10 Image
If you are a COVID-cautious parent, be forearmed that trolls will troll.

Sticks & stones. I knight you a #PublicHealth ambassador. Stand tall. Your work is needed.

Check out Table A5 for what to expect (final page).
engrxiv.org/preprint/view/…

6/10
If you’re a #COVID-cautious #parent, I also hope you’ll read the 1st paragraph of this paper (pg. 3).

✅ You’re doing the right thing
✅ You’re smart
✅ Feel validated
✅ Reference #7 is absolutely damning
✅ Kids deserve a better world

engrxiv.org/preprint/view/…

7/10
H/t 🎩to @sri_srikrishna for the #CorsiRosenthalBox article that inspired my write up.
sciencedirect.com/science/articl…

Thanks also to @JimRosenthal4, @CorsIAQ, @joeyfox85, and others for teaching about air cleaning

8/10
I posted Naomi’s original design, but also check out Greg’s "Pram-PAPR." He’s got a different air filter & older child.

Mine are baby twins, so I’ve got some different models in the paper & will test out more double strollers down the line too.

9/10
Thank you for your advocacy - @MamaWeasleyy, @PTF_org, @Annalisa840917, @mir_ocall, @maskupmama, #ImmunizeUnder5s #covidkids

Please share the #PAPRbuggy & #HEPAbuggy with families of young children!

If I have to 🔒 my account, send the link:
engrxiv.org/preprint/view/…

10/10

• • •

Missing some Tweet in this thread? You can try to force a refresh
　

Keep Current with Mike Hoerger, PhD MSCR MBA

Mike Hoerger, PhD MSCR MBA Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!

PDF

Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @michael_hoerger

Mike Hoerger, PhD MSCR MBA Profile picture
Jul 20
Long COVID Risk Tables

You probably saw this week's NEJM article on #LongCOVID. We did a special section on it in this week's PMC COVID-19 Forecasting Report (pgs 6-8).


THREAD of tables. 🧵🔢

1/
Details:
Our model continues to provide estimates of Long COVID cases that will ultimately result from each day’s infections.

We provide a credible interval that 5-20% of infections will result in Long COVID.

This week, Al-Aly and colleagues reported in the New England Journal that in the more recent era of the pandemic, vaccinated individuals have a 3.5% chance of developing Long COVID from a particular infection.

They focused on medically documented new serious health conditions. We continue to view 5% as a useful lower bound for two reasons.

Long COVID chances were higher in unvaccinated individuals in their study, and there were no analyses based on time since last vaccination.

With many Americans still unvaccinated and many not vaccinated in the past year, the true estimate for a 2024 infection could well surpass 5% for a medically documented new serious health condition.

Moreover, Long COVID is a heterogeneous condition, and many cases are likely not medically documented, especially at the less debilitating end of the spectrum.

The following tables show the risk of ever developing Long COVID from an infection assuming 3.5%, 5.0%, and 20.0% rates.

These statistics document the seriousness of Long COVID with Americans getting infected nearly once a year (average of 12.5 months by our estimates).

However, it is also important to know that some effects are enduring, and others more likely to improve, so many with Long COVID will improve.

Many will also have repeated bouts of Long COVID, likely with different phenotypes.pmc19.com/data/
If you assume 3.5% of people get Long COVID per infection, the risk grows sizably with reinfections, which are happening nearly once per year. Avg of 9 infections/American the next decade.

In the previous Tweet, we note how 3.5% is an obvious underestimate.

2/ What are the chances of developing new Long COVID? Number of Infections | Chances of Long Covid 1 3.5% 2 6.9% 3 10.1% 4 13.3% 5 16.3% 6 19.2% 7 22.1% 8 24.8% 9 27.4% 10 30.0% 15 41.4% 20 51.0% 25 59.0% 30 65.7% 35 71.3% 40 76.0% 50 83.2% 75 93.1% 100 97.2% 150 99.5% 200 >99.9% 300 >99.9% 400 >99.9% 500 >99.9%
Based on that 3.5% estimate, a more realistic low-ball estimate of serious long COVID is 5-7%, given that not all serious new health conditions are documented in medical records & rates are higher among those unvaxxed or not recently vaxxed.

Bad decade (9 inf's) ahead.

3/ What are the chances of developing new Long COVID? Number of Infections | Chances of Long Covid 1 5.0% 2 9.8% 3 14.3% 4 18.5% 5 22.6% 6 26.5% 7 30.2% 8 33.7% 9 37.0% 10 40.1% 15 53.7% 20 64.2% 25 72.3% 30 78.5% 35 83.4% 40 87.1% 50 92.3% 75 97.9% 100 99.4% 150 >99.9% 200 >99.9% 300 >99.9% 400 >99.9% 500 >99.9%
Read 6 tweets
Mike Hoerger, PhD MSCR MBA Profile picture
Jun 28
PMC COVID-19 Forecast, June 28, 2024 (U.S.)

You've got about 1 good month left for higher risk medical and dental visits.

Expect 500,000 to 600,000 infections/day the next month -- in a summer "lull."

1/CURRENT ESTIMATES FOR June 28, 2024 Wastewater Levels (copies/mL) 367 New Daily Cases 534,000 % of Population Infectious 1.12% (1 in 90 people) New Daily Long COVID Cases 4-WEEK FORECAST FOR July 26, 2024 Wastewater Levels (copies/mL) 415 (13% higher) New Daily Cases 586,000 % of Population Infectious 1.23% (1 in 82 people) New Daily Long COVID Cases 29,000 to 117,000
PMC COVID-19 Forecast, June 28, 2024 (U.S.)

1.1% of the U.S. is actively infectious (1 in 90). We're looking at 3.7 million infections/week and 187,000+ resulting Long COVID cases/week.

That's 129 million infections in 2024 so far.

2/There is more COVID-19 transmission today than during 44% of the pandemic. CURRENT ESTIMATES FOR June 28, 2024 Wastewater Levels (copies/mL) 367 New Daily Cases 534,000 % of Population Infectious 1.12% (1 in 90 people) New Daily Long COVID Cases 27,000 to 107,000 WEEKLY ESTIMATES FOR June 28, 2024 New Weekly Cases 3,700,000 New Weekly Long COVID Cases 187,000 to 748,000 2024 CUMULATIVE ESTIMATES AS OF June 28, 2024 Total 2024 Cases To Date 129,801,250 Total 2024 Long COVID Cases To Date 6,490,000 to 25,960,000 4-WEEK FORECAST FOR July 26, 2024 Wastew...
PMC COVID-19 Forecast, June 28, 2024 (U.S.)

How does transmission compare to late June in past years?

2023: 1.9x higher today
2022: 2.3x higher in 2022 (BA.2 surge) than today
2021: 5.6x higher today
2020: 2.8x higher today

We're in a hot "lull" with #backtoschool soon.

3/Zoomed in version of "whole pandemic" graph from the prior Tweet. The rates show how transmission varies presently versus this time in prior years.
Read 6 tweets
Mike Hoerger, PhD MSCR MBA Profile picture
Apr 29
PMC COVID-19 Forecast, April 29, 2024 (U.S.)

Transmission continues to decline. About 1 in 161 people in the U.S. are infectious, the lowest levels since July 1. Transmission levels are higher than during 27% of the pandemic, but a good time to catch up on delayed care.
1/4 There is more COVID-19 transmission today than during 27.7% of the pandemic. CURRENT ESTIMATES FOR April 29, 2024 Wastewater Levels (copies/mL) 203 New Daily Cases 296,000 % of Population Infectious 0.62% (1 in 161 people) New Daily Long COVID Cases 15,000 to 59,000 WEEKLY ESTIMATES FOR April 29, 2024 New Weekly Cases 2,100,000 New Weekly Long COVID Cases 104,000 to 414,000 2024 CUMULATIVE ESTIMATES AS OF April 29, 2024 Total 2024 Cases To Date 105,544,710 Total 2024 Long COVID Cases To Date 5,277,000 to 21,109,000 4-WEEK FORECAST FOR May 27, 2024 Wa...
I have some concerns about Biobot's real-time data quality at the moment. Their real-time data have over-reported levels the past 8 weeks (11% last week, previously 6%, 10%, 7%, 5%, 9%, 4%, 5%) relative to later corrections. Huge bias!
2/4
Qualitatively, the over-reporting in real-time data lead me to believe there's a 50-50 chance we see a May "wavelet" versus continued decline for a couple months. Some of the county-level Biobot data seem implausible (e.g., levels of "3" in Mason County, WA, but others too).
3/4 Mason County, WA Levels of 3 copies/mL, per Biobot. About 1 in 10,000 actively infectious, if accurate.
Read 4 tweets
Mike Hoerger, PhD MSCR MBA Profile picture
Mar 1
31 Reasons Why the New 1-Day COVID Isolation Policy is Wrong

#1
Experts in modeling and testing know that people are infectious with COVID for an average of 7 days, with substantial variability around that average.

"31 Reasons Why the New 1-Day COVID Isolation Policy is Wrong"
#2
People use defense mechanisms to temporarily avoid the death anxiety evoked by thinking of COVID. The too-short 5-day iso was an example of this (see final example).

Such defenses provide temporary relief and are almost always harmful long-term.
#3
Dropping isolation policies to 1 day will predominantly harm people in poor-ventilation environments.

Restaurants have 35-50x less ventilation than the ASHRAE standards, so this will harm the service industry and unsuspecting “brunch class.”
Read 31 tweets
Mike Hoerger, PhD MSCR MBA Profile picture
Feb 29
PMC COVID-19 Forecast, Week of Feb 26, 2024
1 of 5 🧵

Forecast for the next month
Over the next month, we should see transmission fall from 790,000 infections/day toward more like a range of 200,000-450,000 infections per day, depending on better or worse scenarios.

That's "good" news in the relative sense for those putting off medical appointments the past 6 months, though still extremely high transmission in any objective sense.

See the online report for details on the models.

Surge in Context
At this point in the surge, it is clear that the peak transmission day was around December 27 (1.92 million/day), and the midpoint of “surging” infections (>1 million/day) was around January 9.

We are estimated to have had 85 total days with >1 million infections per day (November 28 through February 20) during the surge, though these numbers may still fluctuate with corrections the next few weeks.

The low-point leading into the surge was October 18 at 547,000 infections/day. Infections have been at “wave” levels (>500,000 infections/day or higher) since the onset of the late summer wave surpassed that milestone on July 27. We are estimated to dip below 500,000 infections/day around March 6.

This is very unfortunate timing because the medical facilities that enacted universal masking may end policies on March 1. Many were hoping for a period of lower transmission before such policies ended. As of today, the estimated low point for transmission is March 27 (348,000 infections/day), but the level and date are subject to much uncertainty.CURRENT ESTIMATES FOR February 26, 2024 Wastewater Levels (copies/mL) 546 New Daily Cases 794,000 % of Population Infectious 1.66% (1 in 60 people) New Daily Long COVID Cases 40,000 to 159,000 4-WEEK FORECAST FOR March 25, 2024 Wastewater Levels (copies/mL) 242 (-56% lower) New Daily Cases 353,000 % of Population Infectious 0.74% (1 in 135 people) New Daily Long COVID Cases 18,000 to 71,000
PMC COVID-19 Forecast, Week of Feb 26, 2024
2 of 5 🧵

Current State of the Pandemic
🔹73 million infections in the U.S. in 2024 (so far)
🔹790,000 daily infections
🔹1.66% (1 in 60) actively infectious
🔹40,000+ resulting #LongCOVID cases/day

Deeper Dive
Transmission is finally starting to decline again, and expect major declines the next four week.

U.S. wastewater levels indicate that COVID transmission is higher than during 58.4% of the days of the pandemic (down from 85.9% a week ago). Transmission is lower than 41.6% of the pandemic.

As we noted the past two weeks, we believed the post-peak hill was itself peaking on around February 7th and that last week’s slightly higher values might get retroactively corrected downward. That was, in fact, the case (the peak was the 7th), and transmission has fallen further since.

We are still at very high “wave” levels, but no longer “surging” at over a million infections/day. The big picture remains very bad, but this is good news for people putting off medical appointments for months.There is more COVID-19 transmission today than during 58.4% of the pandemic. CURRENT ESTIMATES FOR February 26, 2024 Wastewater Levels (copies/mL) 546 New Daily Cases 794,000 % of Population Infectious 1.66% (1 in 60 people) New Daily Long COVID Cases 40,000 to 159,000 WEEKLY ESTIMATES FOR February 26, 2024 New Weekly Cases 5,600,000 New Weekly Long COVID Cases 278,000 to 1,112,000 2024 CUMULATIVE ESTIMATES AS OF February 26, 2024 Total 2024 Cases To Date 73,585,610 Total 2024 Long COVID Cases To Date 3,679,000 to 14,717,000
PMC COVID-19 Forecast, Week of Feb 26, 2024
3 of 5 🧵

Risks in Group Settings
Although transmission is falling, it's easy to get distracted by the relative changes and ignore that the absolute risk remains high, especially in large groups with limited or no mitigation.

In a group of 10, there's a 15% at least one person is actively infectious. In a group of 30, it's a 40% chance, and so forth. Almost nobody would take those chances of a serious illness if informed and capable of grappling with the seriousness of that risk without becoming defensive. Unfortunately, a lot of institutions are pushing minimizer narratives if not directly forcing students and workers into more dangerous settings.How Does Risk Increase with More Social Contacts? Number of People | Chances Anyone is Infectious 1 1.7% 2 3.3% 3 4.9% 4 6.5% 5 8.0% 6 9.6% 7 11.1% 8 12.5% 9 14.0% 10 15.4% 15 22.2% 20 28.5% 25 34.2% 30 39.5% 35 44.4% 40 48.8% 50 56.7% 75 71.5% 100 81.3% 150 91.9% 200 96.5% 300 99.3% 400 99.9% 500 >99.9%
Read 5 tweets
Mike Hoerger, PhD MSCR MBA Profile picture
Feb 8
New book about to drop.

1/4
Ralph Nader's "Unsafe at Any Speed: The designed-in dangers of the American automobile," cover modified to "COVID-19 Unsafe as we breathe: The designed-in dangers of the California 1-day isolation policy"
Dr. Moriarty & other modelers know people are infectious for an average of about 7 days, per high-quality studies. Many for much longer.

Dr. Mina's pinned Tweet lays out a sample timeline.

Sending kids to school on Day 2 positive will essentially maximize infections.
2/4 Pinned tweet from Michael Mina showing a heuristic infection timeline for an individual patient. Sending someone to school 1 day after positive basically means they're being sent to school right at peak infectiousness.
The consequence of the California 1-day isolation policy is that many parents and grandparents will develop serious health conditions and too often die prematurely.

Bad for families. Good for inspiring the next generation of bereavement workers.

3/4
Read 4 tweets

Did Thread Reader help you today?

Support us! We are indie developers!

This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Don't want to be a Premium member but still want to support us?

Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal

Or Donate anonymously using crypto!

Ethereum

0xfe58350B80634f60Fa6Dc149a72b4DFbc17D341E copy

Bitcoin

3ATGMxNzCUFzxpMCHL5sWSt4DVtS8UqXpi copy

Thank you for your support!

Follow Us!

Send Email!

:(