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
Dec 17, 2022 • 21 tweets • 9 min read • Read on X
Scrolly
THREAD: 19 Tips for a DIY mask fit test to reduce your risk of #COVID19.

H/t @amandalhu & @__philipn__

What did I miss? Assorted fit-testing pictures
Fit-testing Tip #1: Keep it Simple.

Get a nebulizer (usually $30-40) & some 3M FT-32 Bitrex solution ($24). The FT-32 fit-test solution (right) goes in the nebulizer. J
Fit-testing Tip #2: Taste the Failure.

Use the nebulizer to spray the bitrex solution (barely visible). Breathe through your mouth. If you taste it, there’s a mask leak.

"It’s not rocket science," as @CorsIAQ likes to say.
Fit-testing Tip #3: Spray at Problem Areas.

I use the nebulizer to spray bitrex fit-testing solution all around the nose bridge, by both cheeks, and under the chin.

You’ll quickly taste a leak. Spray all around the edge of the mask. Make a big loop. Focu
Fit-testing Tip #4: Go Hoodless.

Do what ya wanna, but for DIY fit testing, the method above works fine w/o the hood.

I bought a hood – overpriced! Plus, the goal is to get as many people as possible fit testing. Many would find them off-putting or feel claustrophobic. Me wearing a fit-testing hood. In my view, not needed for DI
Fit-testing Tip #5: Don’t Test around Maskless People/Animals.

After reinstalling a new filter on my Flo Mask, I did a fit test while my son was having a bath. He started coughing. For a moment, I worried he had COVID.

Put 2&2 together, cranked up the HEPA & gave him juice. Don't test around other people or animals. If too much bitre
Fit-testing Tip #6: Have a Beverage Handy.

You’re testing for leaks. You will find some. The bitrex tastes horrible, like licking a rubber band. Have some OJ or a soda ready for after you’re done.
Fit-testing Tip #7: Share the Wealth.

Supplies cost $60 total. It takes hardly any fit-testing solution to test, so offer the opportunity to friends, family, or co-workers. You’ll help protect their health & better cocoon yourself from illness too.

Wise investment. Protect those in your "pods" or "bubbles"
Fit-testing Tip #8: Wear and N95 or #BetterMask.

I tested all 3 of my favorite N95s: the Aegle flat-fold, 3M Aura, and 3M VFlex. I could pass a fit test with each, some caveats noted later. Aegle, 3M Aura, 3M VFlex
Fit-testing Tip #9: Select the Best N95 for YOUR Face.

If you have several masks, test and compare. Go with the winner.

For me, the 3M VFlex held up most robustly. The 3M Aura needs to be readjusted if I talk to much. The Aegle is harder to seal at the nose. The 3M VFlex passed a fit test most easily and robustly, whe
Fit-testing Tip #10: Get your best N95 to fit better.

Although the 3M VFlex most easily & robustly passed fit-testing, I realized I hadn’t been pulling it back far enough under the chin (@jasmith_yorku). I also learned how best to adjust the nose piece to get the best fit. Dr. James showing off how to wear the under-chin region of t
Fit-testing Tip #11: Elastomeric Masks beat N95s.

I tested 6 elastomeric masks. I hate the word “elastomeric.” It’s alienating.

They’re just non-disposable, reusable masks. Great seal. All outperformed my disposable N95s when testing the limits. I'm wearing the Flo Mask, my go-to elastomeric. It's the mos
Fit-testing Tip #12: Get your Elastomeric to Fit Better.

Straps can wear out or loosen over time! Filters also need to be reinstalled properly. Use fit testing periodically and when installing new filters to confirm no leaks. Flo Mask filter. I added a cancer ribbon (safe). Put the fil
Fit-testing Tip #13: Procedure Masks are a Joke.

Fit tested, fails in <0.5 sec. Air flows to the path of least resistance. Gaps poorly guard against inhaling/exhaling viral-laden aerosols.

Everybody should be using #BetterMasks, paid w/public funds.
Fit-testing Tip #14: Cloth Masks are ALSO a Joke.

Also tested a cloth mask. Fails in <0.5 sec. Viral-laden aerosols are too small. Not good enough for 2022.

Everybody should be using #BetterMasks, paid w/public funds.
Fit-testing Tip #15: Fit-test Ear-Loop Masks.

I don't wear ear-loop masks (many KN95/KF94). My experience fit-testing makes me skeptical of cheek gaps.

Worrisome if spending much time in a poorly-ventilated space (car, plane, school, office).
Fit-testing Tip #16: Check for Counterfeits.

Many KN95/KF94 masks are counterfeits, especially on Amazon. Even the city of New Orleans distributed fakes “N95s” last winter. Use fit-testing to check whether a mask is legitimate.
thelensnola.org/2022/01/14/cit…
Fit-testing Tip #17: Facial Hair is a COVID Risk.

My disposable N95s start to fail fit-testing after about 2.5 days w/o shaving. My elastos make it about 3.5 days. If you’re clean-shavin, keep it clean.

If you prefer facial hair, use a mask-safe cut, or know the risk. Facial hair can create mask leaks, increasing COVID risk. Kn
Fit-testing Tip #18: DBAA.

No, fit-testing is not REQUIRED for masks to “work.”

It’s about improving safety on the margins (5-10%) and especially for the most dangerous prolonged contexts.
osha.gov/laws-regs/stan…. https://www.osha.gov/laws-regs/standardinterpretations/2018-
Fit-testing Tip #19: Who to Follow.

H/t to @amandalhu and @__philipn__ for teaching me about fit testing!


FYI, I have no conflicts of interest, such as investing in one of the companies mentioned.

I’m a psychologist just trying to help people understand COVID mitigation tips I didn’t know a year ago so maybe you can reduce your lifetime number of cumulative SARS-CoV-2 infections.

• • •

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
Jan 17
Based on today's CDC & Biobot data, we estimate the following for the week of Jan 19:

🔸1 in 52 people in the U.S. actively infectious
🔸25% chance of exposure in a room of 15 ppl
🔸Nearly 1 million new daily infections
🔸5 cumulative infections per person all-time (avg)
🧵1/5 Heat map from CDC data with PMC estimates. Description of "Very High" states in next post
Transmission estimates have been marginally corrected upward.

11 states have Very High COVlD levels:

🔸PA: 1 in 25 estimated actively infectious
🔸MI: 1 in 23
🔸OH & KY: 1 in 22
🔸SD: 1 in 20
🔸NE & IA: 1 in 18
🔸IL & ME: 1 in 17
🔸IN: 1 in 16
🔸WV: 1 in 11
🧵2/5 Proportion Actively Infectious 1 in 52 (1.9%) New Daily Infections 941,000 Infections the Past Week 6,020,000 Infections in 2026 18,000,000 Cumulative Infections per Person 5.01 Long COVID Long COVID Cases Resulting 47,000 to 188,000 from New Daily Infections Long COVID Cases Resulting 301,000 to 1,200,000 from New Weekly Infections Excess Deaths Excess Deaths Resulting 270 to 450 from New Daily Infections Excess Deaths Resulting ...
We're in the middle of a 12th COVlD wave.

The peak has likely passed, but with students headed back to school, transmission is expected to remain high for at least the next several weeks.

🧵3/5 1) Graph of 12 waves 2) Barometer showing above-average transmission 3) Year over year graph 4) Forecast for transmission to decline and then percolate at high levels
Read 5 tweets
Mike Hoerger, PhD MSCR MBA Profile picture
Jan 10
The size of the winter COVlD wave has been revised upward as post-holiday data come in.

We estimated 1 in 55 people in the U.S. are actively infectious.

🔥WV: 1 in 14
🔥IN: 1 in 15
🔥MI & OH: 1 in 21
🔥MO: 1 in 22
🔥CT: 1 in 24
🔥KS: 1 in 25
🔥MA & IL: 1 in 27

Quick 🧵 1/4 Heat map and PMC estimates, 1 in 55 infectious and 892,000 new daily infections for Jan 12. We expedited the report to release it two days early.
Nationally, we are seeing an estimated 892,000 new daily SARS-CoV-2 infections, meaning a 1 in 4 chance of exposure in a room of 15 people. Risk varies considerably by state.

We are approaching an average of 5 infections per person since pandemic onset.
🧵 2/4 Alabama Moderate Alaska Very Low Arizona Very Low Arkansas High* California Very Low Colorado Low Connecticut Very High Delaware Moderate District of Columbia Very Low Florida Very Low Georgia Very Low Guam Very Low Hawaii Very Low Idaho Very Low Illinois Very High Indiana Very High Iowa High Kansas Very High Kentucky Moderate Louisiana Moderate Maine High Maryland High Massachusetts Very High Michigan Very High* Minnesota Moderate Mississippi Low* Missouri Very High* Montana High Nebraska High Nevada Very Low New Hampshire Moderate New Jersey Low New Mexico Moderate New York High* North Ca...
We are in the 12th COVlD wave of the U.S.

Current transmission is higher than 68% of all days since the pandemic onset in 2020.
🧵 3/4 12 waves of COVlD Pandemic barometer: Higher than 88% of the past 100 days, 73% of the past year, 68% of the entire pandemic. Year over year graph Forecast of slowly declining transmission.
Read 4 tweets
Mike Hoerger, PhD MSCR MBA Profile picture
Jan 8
You might not have heard, but the northeastern U.S. is in a COVlD surge.

We use wastewater levels to derive estimates of the proportion of people actively infectious in each state (prevalence), e.g., 1 in 24 people in Connecticut.

Let me walk you through it...

🧵1/8 Colors show CDC levels PMC prevalence estimates noted: -Maine 1 in 38 actively infectious with COVlD -New Hampshire 1 in 35 (limited data) -Vermont 1 in 75 -New York 1 in 44 (limited data) -Pennsylvania 1 in 44 -Massachusetts 1 in 36 -Connecticut 1 in 24 -Rhode Island 1 in 41 -New Jersey 1 in 82
Notice that #Connecticut has excellent SARS-CoV-2 wastewater surveillance. It's "Very High" across much of the state, per CDC.

Based on wastewater levels, we estimate 1 in 24 residents are actively infectious w/COVlD. That's a 66% exposure risk in a room of 25 people.

🧵2/8 Colors show CDC levels PMC estimate of prevalence
The CDC reports "Very High" levels in #Massachusetts.

The surveillance is less robust, but we estimate 1 in 26 residents are actively infectious, similar to our estimate in CT where coverage is better.

In a room of 25 people, that's a 62% chance of an exposure.

🧵3/8 Colors show CDC levels PMC prevalence estimates provided
Read 8 tweets
Mike Hoerger, PhD MSCR MBA Profile picture
Jan 8
We're in the middle of a 12th COVlD wave in the U.S., with transmission particularly high in the Midwest and Northeast.

The CDC announced this week that COVlD continues to kill more Americans than breast and prostate cancer combined.

Get boosted & #MaskUp 💉💪😷
1/4🧵 Heat map of CDC data with PMC prevalence estimate
Levels are "Moderate" to "Very High" in 26 states.

However, data reporting is slow, and about 1/3 of states have low-quality data this week due to the holidays and illness.

2/4🧵 National estimates: Number of People Chances Anyone is Infectious 1 1.5% 2 3.0% 3 4.5% 4 6.0% 5 7.4% 10 14.3% 15 20.7% 20 26.5% 25 32.0% 30 37.0% 50 53.8% 75 68.6% 100 78.6% 200 95.4% 300 99.0%
Barometer: Higher transmission than 90 of the past 100 days (perhaps higher still, due to low data reporting quality)
State CDC Level Actively Infectious Alabama Moderate 1 in 48 (2.1%) Alaska Very Low 1 in 152 (0.7%) Arizona Very Low 1 in 201 (0.5%) Arkansas High* 1 in 36 (2.8%) California Very Low 1 in 484 (0.2%) Colorado Moderate 1 in 49 (2.0%) Connecticut Very High 1 in 24 (4.2%) Delaware Low* 1 in 70 (1.4%) District of Columbia Very Low 1 in 5,835 (0.0%) Florida Very Low 1 in 284 (0.4%) Georgia Low 1 in 90 (1.1%) Guam Very Low 1 in 687 (0.1%) Hawaii Very Low 1 in 874 (0.1%) Idaho Very Low 1 in 169 (0.6%) Illinois Moderate* 1 in 56 (1.8%) Indiana High* 1 in 34 (2.9%) Iowa Moderate 1 in 41 (2.4%) Kansas...
State CDC Level Actively Infectious Missouri Moderate* 1 in 42 (2.4%) Montana High 1 in 34 (2.9%) Nebraska Very High 1 in 26 (3.9%) Nevada Very Low 1 in 138 (0.7%) New Hampshire High* 1 in 35 (2.9%) New Jersey Low 1 in 82 (1.2%) New Mexico Low 1 in 87 (1.2%) New York Moderate* 1 in 44 (2.3%) North Carolina Low 1 in 82 (1.2%) North Dakota High* 1 in 34 (3.0%) Ohio Very High 1 in 27 (3.7%) Oklahoma Moderate* 1 in 62 (1.6%) Oregon Very Low 1 in 170 (0.6%) Pennsylvania Moderate 1 in 44 (2.3%) Rhode Island Moderate 1 in 41 (2.4%) South Carolina Moderate 1 in 54 (1.9%) South Dakota Very High 1 in...
If like years 1-4 of the pandemic, the winter wave has peaked. If like last year, we could hover near peak levels for a month.

Forecasting quality is low with 1/3 of states having data issues. Hopefully, we'll know a lot more in a few days.

3/4🧵 12 waves
Proportion Actively Infectious 1 in 65 (1.5%) New Daily Infections 749,000 Infections the Past Week 5,390,000 Infections in 2026 3,000,000 Cumulative Infections per Person 4.88 Long COVID Long COVID Cases Resulting 37,000 to 150,000 from New Daily Infections Long COVID Cases Resulting 270,000 to 1,080,000 from New Weekly Infections Excess Deaths Excess Deaths Resulting 220 to 370 from New Daily Infections Excess Deaths Resulting ...
year over year graph
forecast
Read 4 tweets
Mike Hoerger, PhD MSCR MBA Profile picture
Jan 5
We told you that 109,000-175,000 Americans would died of COVID (excess deaths) in 2025.

Today, the CDC estimates 101,000 deaths/year (flat from Oct 2022 to Sep 2024), and likely higher when considering more nebulous non-acute excess deaths (heart attack 6 months later).
1/5
The CDC estimates are actually higher than I would have guessed, given their methodology, which models estimates based on easily countable factors in healthcare and expert input on multiplier values. It lends credence to the PMC upper bound of excess deaths of 175,000/yr.
2/5
What's troubling is the CDC has annual mortality flat. My expectation based on mortality displacement and Swiss Re data is that it should be declining. If is stays flat, we're running on something like breast+prostate cancer or lung cancer deaths per year in perpetuity.
3/5
Read 6 tweets
Mike Hoerger, PhD MSCR MBA Profile picture
Dec 31, 2025
PMC COVlD Update, Week of Dec 29, 2025
🧵1/10

Happy New Year's Eve! #nye

Based on today's CDC data, we estimate 1 in 51 Americans are actively infectious with COVlD. That's nearly 1 million new daily infections.

Be wise. Vax up, mask up. #oneofthetwo Heat map from CDC data and PMC estimates.
🧵2/10

Many states are surging presently. True levels are higher than shown in most places due to state-level reporting lags. Alabama Moderate 1 in 46 (2.2%) Alaska Low 1 in 93 (1.1%) Arizona Very Low 1 in 201 (0.5%) Arkansas High* 1 in 32 (3.1%) California Very Low 1 in 351 (0.3%) Colorado Low 1 in 71 (1.4%) Connecticut High 1 in 33 (3.1%) Delaware Low 1 in 90 (1.1%) District of Columbia Very Low 1 in 300 (0.3%) Florida Very Low 1 in 282 (0.4%) Georgia Very Low 1 in 125 (0.8%) Guam Very Low 1 in 585 (0.2%) Hawaii Very Low 1 in 855 (0.1%) Idaho Very Low 1 in 221 (0.5%) Illinois Moderate 1 in 41 (2.5%) Indiana Very High 1 in 14 (6.9%) Iowa Low 1 in 69 (1.4%) Kansas Moderate 1 in 46 (2.2%) Kentucky High 1 in 34 (2.9...
🧵3/10

Although many states are surging, do not feel false security in "low" level states. For example, NY has terrible reporting quality with the CDC currently. Missouri Moderate* 1 in 56 (1.8%) Montana Low 1 in 76 (1.3%) Nebraska Very High 1 in 18 (5.5%) Nevada Very Low 1 in 122 (0.8%) New Hampshire Moderate* 1 in 42 (2.4%) New Jersey Very Low 1 in 113 (0.9%) New Mexico Moderate 1 in 62 (1.6%) New York Very Low* 1 in 127 (0.8%) North Carolina Very Low 1 in 125 (0.8%) North Dakota Moderate* 1 in 43 (2.3%) Ohio High 1 in 28 (3.6%) Oklahoma Very High 1 in 25 (4.0%) Oregon Very Low 1 in 170 (0.6%) Pennsylvania Moderate 1 in 45 (2.2%) Rhode Island Moderate 1 in 41 (2.4%) South Carolina Low 1 in 84 (1.2%) South Dakota High 1 in 33 (3.0%) Tennessee Moder...
Read 10 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!

:(