Share this page!

Joshua C. Agar Profile picture
Twitter logo
11 Oct, 31 tweets, 9 min read
Debacle of face shields in the Philippines

(A thread)

I see that some of the scientists from other countries are considering recommending face shields to be worn in public.

I beg to differ, presenting how face shields represented the poorest pandemic response in the world.
December 11, 2020

The Inter-Agency Task Force (IATF) against Covid-19 of the Philippine Government, through its Resolution no.88, mandated the use of face shields even in public, outside of hospital settings.
pna.gov.ph/articles/11544….
The technical advisory body of the IATF, spearhead by infectious disease experts Dr. Anna Lisa Ong-Lim and Dr. Edsel Salvana claimed that a randomized control trials (RCT) conducted in the public hospitals and another performed in India reported 90% efficacy rate.
You can hear Ong-Lim making that claim in this live radio interview:
facebook.com/dzbb594/videos…
It should be noted that face shields are in fact physical interventions, so physical experiments and simulations, rather than Randomized Control Trials, should be done to evaluate its effects against the transmissions of respiratory diseases.
A study headed by William Lindsley of the National Institute of Occupational Safety and Health (NIOSH), under CDC, conducted experiments pertaining to face shields. ncbi.nlm.nih.gov/pmc/articles/P…
The finding was that it was effective against the initial impact of droplets (confirming its purpose to be solely to be against ballistic transmissions), however poor against aerosols that lingered longer in the air, which recirculates to within, posing risk to be inhaled.
The face shields are one of the contraptions that the government mandated as they claimed that these were offering protection against Covid-19.
philstar.com/headlines/2020…
Around the same month (Dec 2020), researchers from the Fukuoka University expressed concerns whether the face shields were offering protection in the first place.

physicsworld.com/a/face-shields…
The eddies generated by the turbulent effects will just go around the barrier and carry the viral copies to the person still.
Amidst the surge from the UK Variant in June 2021, the president, Duterte, initially lifted face shields, but then rescinded the order. This brought to question whether the intent of face shields are for protection in the first place.

interaksyon.philstar.com/politics-issue…
The initial inferences from the wind engineering side gained traction a week later:
The aerodynamic effects are summarized here in this diagram:
The aerodynamic effects being validated using the tissue test:
Another validation using anemometers:
Visualization of the aerosols still making its way behind the face shield:
News agencies picking up the observations (June 28): news.abs-cbn.com/video/news/06/…
A GMA 7 segment covering the initial observations:
Even so, the DOH, as represented by Dr. Ong-Lim here, are insistent:
facebook.com/dzbb594/videos…

Dr. Maricar Limpin, heading the Philippine Medical Association, supported the retention of the face shield.
Dr. Salvana attempted to counter the observations presented by the wind engineering side by quoting Wendling et al. (2021) who performed experiments. However, the authors of this paper conceived the test setup from a ballistic approach, still droplets.
pubmed.ncbi.nlm.nih.gov/33671300/
A visualization experiment by the Florida Atlantic University already determined face shields are poor source control.
aip.scitation.org/doi/10.1063/5.…
An analysis using computational fluid dynamics (CFD) revealed that face shields increase the risk of airborne transmissions.

This gained traction again since there was an ongoing surge of the delta variant that time:
With the revelations on government corruption on face shields again, the media coverage resumed.
The medical side was also asked an opinion about it, with Dr. Limpin slipping that they are still running on the assumption of heavy droplets, and the Dans couple, being posers on knowing airborne transmissions, insisted that RCTs provide better answer.
Then came the Caloocan SDGCon 2021...
One of the plenary speakers in the event was @jljcolorado , who presented the fact that #COVIDisAirborne . The Department of Health (presented by Dr. Beverly Ho) presented along with some MDs.

Video of the proceedings:
facebook.com/watch/live/?re…
The DOH who has been running on the assumption of heavy droplets, suddenly pandered with @jljcolorado 's presentation and presented that Covid-19 is airborne. The measures presented, however, implies that DOH doesn't fully understand how airborne transmissions work.
The DOH still insisted on face shields.

Remember that @WHO supported this insistence by DOH.

cnnphilippines.com/news/2021/9/7/…
And look at the Philippines now: rated of having the worst pandemic response.

This is not only because of the incompetence of government, but also of the grave miscalculations of the public health sector.

Acknowledging #COVIDisAirborne is different from understanding it. [END]
Erratum:

Dr. Limpin is the president of PCP, not PMA.

• • •

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

Keep Current with Joshua C. Agar

Joshua C. Agar 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 @JoshuaCAgar

Joshua C. Agar Profile picture
12 Oct
And as it turns out, the initiative of exploring the potential for wind power that led to the wind farms in Ilocos Norte...

...came from USAID!

The Marcoses have been consistent of grabbing credit from USAID!

Documentation of the Initiative:
nrel.gov/docs/fy02osti/… Image
The study of compiling the atlas for wind energy in the Philippines started in 1996. The atlas was finished at 2000:

(Lol. They indeed did GEV analysis and interpolated using the projected wind exposure parameters) Image
Bangui and Burgos became the ideal locations. Northwind invested on Bangui and First Gen invested on Burgos. Image
Read 4 tweets
Joshua C. Agar Profile picture
12 Oct
Re: Face shields on various scenarios (Another thread)

I was asked, in the spirit of the RCTs, whether I have explored the other scenarios concerning face shields.

Well, yes, I did.
The intervention of face shields against sporadic emissions at different angles of attack was simulated and observed, and as it turned out that the ballistic protection only applies for emissions coming from the front. From other angles, risk increases:

The speed of cough simulated was 50 mph. Here, it was illustrated how the momentum of the emission decreases over distance, while also noting the advection also:

Read 10 tweets
Joshua C. Agar Profile picture
12 Oct
Misinformation and falsehoods cascade across three layers:
First is with the perpetrators who spread disorienting misinformation in social media.

Second is with the media on which some are disoriented and pass on the disorientation to the masses.

Third is with the masses.
Indeed, the battleground may be dealing with the source. But the ripples of misinformation still trickled down to its main interest and intended audience: the masses.
Given that the surveys determined that mainstream media are still the main source of information of people, we look at media personalities who package their commentaries, which contained their personal biases, as if those were the news.
Read 6 tweets
Joshua C. Agar Profile picture
10 Oct
Taytay Chronicles w/ Bayaw Erik
(October 10, 2021)
The dreaded face shield
How to assemble and "use" face shields
Read 12 tweets
Joshua C. Agar Profile picture
10 Oct
Kindly ask those "lolo" and "lola" giving anecdotes that "attest" the Marcos regime the year-by-year state of affairs during that period. Ask them the specifics, what specifically happened in '72, '77, '81, '83, 84', and '86.

That's how historiography establishes veracity.
If they can't provide any to establish the veracity of their narrative, then that points of view that they are presenting, like the other dramatis personae in the past making good light of themselves, will be rebuked, shunned, and reprimanded.
You could also ask your lolos and lolas about their knowledge of how government works, the separation of powers, their knowledge of the constitution.
Read 5 tweets
Joshua C. Agar Profile picture
9 Oct
For the sustained wind criteria in the placement of turbines, one can perform wind spectrum analysis (accurate but hard to interpolate and gather) or generalized extreme value analysis (up to the daily maxima).

Here is the GEV analysis of the weather stations across PH: Image
μ represents the base wind speed, which is the expected annual maximum. σ and ζ represents the steepness ("slope") of the extreme value function. The steeper the extreme value function, the higher the difference between annual max from historical max.
The goal in selecting optimal locations for wind turbines is to have a significant μ, but a lesser σ. However, even after this analysis, one must still project the wind spectra by the evaluation of the wind exposure, which is related to the topography and atmospheric boundaries.
Read 5 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

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

Donate via Paypal Become our Patreon

Thank you for your support!

Follow Us on Twitter!

Like this author's thread?

Get emails when @JoshuaCAgar has new unrolls!

Check out other threads from @JoshuaCAgar!

Read all threads by @JoshuaCAgar

:(