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Learn About COVID-19: Why Do We All Need Masks?

Learn About COVID-19: Why Do We All Need Masks?

Stemming from the need to save masks for US health workers (and other Western countries), the community should not wear masks. There is no scientific evidence to suggest that masks worn by ordinary people are ineffective.

On the other hand, the view of the goal of “flattening the curve” in addition to still appreciating a partial reduction in the number of infections by using surgical masks or homemade cloth masks. The latest biological discovery of the invasion of COVID-19 into human body tissue.

And the cough/sneezing droplets suggest that the mechanism of transmission is not due to aerosols but rather to large droplets. What we need to do is make sure everyone needs a surgical mask.

The surgeon said: “Stop buying masks, it doesn’t work…”. The Centers for Disease Control says that surgical masks are less protective than N95 masks. The CDC recommends that healthy people not use masks, only sick people should use them.

These guidelines have no scientific basis but they stem from the need to give up masks to health workers. In the end, it has unintended consequences: Stigmatizing masked people in the community.

Learn About COVID-19 Why Do We All Need Masks

Contrary to that cultural habit, Asian countries are also flattening the curve or even having a flatter curve from the beginning that encourages or even forces people to wear masks.

Learn About COVID-19 Why Do We All Need Masks

Should We Wear Masks

Surely one thing, whether surgical masks and N95 respirators, if worn incorrectly, do not provide effective protection. But if the stated goal is to smooth out the curve. We cannot claim that other masks are ineffective.

What if the surgical mask was punctured or reduced its ability to transmit to the same extent by the recommended distance more than 6 feet apart or without touching your face? From there, it could double the impact of non-pharmacological interventions (NPI) on flattening curves

Because the CDC does not provide any scientific evidence for the claim that masks are not effective for the community. Here we review the protection of surgical masks. We focus on mechanical reasons.

We conclude that any barrier. Perhaps with a mask can reduce the risk of COVID-19 transmission. If we are soon under pressure to relax the blockade and allow social interaction to revive the economy.

Then using masks will play a large role and can facilitate an acceptable approach.


Of course, there are no loose masks, N95 masks or surgical masks that offer 100% protection. However, imperfect protection does not mean that it is completely useless.

Because a full glass does not mean to be completely empty: I am willing to have a full glass of water up to 60% when I’m thirsty. No evidence does not mean no evidence.

But in our binary world, when it comes to the message that surgical masks are not effective. It may be wrong to give them: that they are utterly useless. Unfortunately, with the black-and-white picture drawn by officials.

But with the stated goal of flattening the curve, we have an inverse relationship to the specific goal. Putting the concept of partial protection on a new page.

In principle one can calculate the Y curve based on the protection level of X% by mask. But first we need to understand the details of the mechanism and the biology of the disease.


How airborne viruses transmitted from person to person is a complex, underestimated issue. Possible drops are divided into two large categories based on size.

a) Droplets below the diameter of 10 micrometer

The upper size limit for the definition of aerosol anise. For brevity, let’s call this category aerosols. These small aerosols carry either ventilated or windy and can thus pass through rooms.

What makes N95 masks different from surgical masks is that the front is designed to prevent aerosol: they must filter 95% of droplets smaller than 0.3 um.

b) Droplets larger than 10 micrometer, reaching 0.1mm or more.

We call these large particles “droplets” (For a more detailed discussion, see Nicas and Jones, 2009). Of course, the droplets may be even larger, up to the size visible to the naked eye in a spray bottle created by coughing or sneezing.

Calculations by Xie et al. shows that if exhaled, droplets > 0.1 mm can evaporate or fall to the surface within 2m, air humidity and temperature. But coughing or sneezing can shoot them like bullets out of their mouth at a speed of 50 meters per second (for sneezing) or 10 m/s (for coughing) and water droplets can reach distances as far as 6m.

If so, then the safe distance mentioned at most 6 feet in social encounters may not be enough – except you wear a mask afterwards.

Learn About COVID-19 Why Do We All Need Masks

The biological meaning that distinguishes aerosols from aerosols:

The airborne particles are transmitted and deep into the lungs. Through all the air ducts down to alveolar cells where the gas exchange takes place.

It must be small: only droplets less than 10 micrometers in diameter can reach the alveoli. In contrast, large spray droplets are trapped in the nose and throat and in the upper airways of the lungs, trachea and large bronchi.

The droplets of a typical cough have a size distribution of about half of the drops in aerosol types. Although they represent less than 1/100,000 of the volume transferred (Nicas et al. 2005).

Therefore, following sophisticated N95 masks, designed to filter out the smallest particles. Helps prevent droplets of virus carrying virus into the alveoli. But is this really suitable for flattening the curve? We will see below.

On the contrary:

It is logical that the last large droplets in the nasopharynx can be blocked by any physical barrier. Such as a surgical mask or a simpler dust mask.

Learn About COVID-19 Why Do We All Need Masks

Of course many drops of aerosol during exhalation or coughing may not contain the virus, but some will. In the case of COVID-19, it is not known what the minimum infectious load.

The implicit notion at the CDC that alveolae is the destination for the droplets to transmit the virus, has raised the obvious importance of the mask. N95 toxicity and led to the removal of the obvious importance of N95 mask and led to the removal of surgical masks.

Even for small aerosols, we must not forget that the partial filter provided by the surgical mask is still better than nothing.

In a simulation of the mask’s ability to filter in 2008, van der Sande and her colleagues in the Netherlands compared three masks: homemade fabric, standard surgical masks and FFP2.

Equivalent to a N95 respirator in Europe, involves the ability to prevent small aerosols within the range of 0.2 to 1 umdroplet from reaching the lower lung.

The authors found that internal protection ensured some questions about the CDC message that surgical masks were ineffective.

While the FFP2 (or N95) respirator actually filters >99% of particles, the surgical mask reduces the number of aerosol drops behind the mask still 4 times significantly compared to the outside of the mask. The logical thing is that for larger spray droplets from coughs, the difference between the surgical mask and the F95 gas mask is even smaller.

Interestingly, for exterior protection, the effect and difference are much smaller.

These results raise the urgent question:

If all we want is to reduce pandemics, that is, straighten the curve. How many times the particles to the lungs can reduce the number of human-to-human transmissions?

Intuition suggests that even an imperfect mask can be a safeguard at least within a recommended distance of more than 6 feet when socializing or washing your hands or not touching your face – All recommendations are based on mechanical rationality without any epidemiological support.

Technically, one can quantify by reducing the water droplet a person touches 4 times like a surgical mask. Or 3 times as achieved by a temporary cloth mask. Which contributes to reduce the ratio from initial R0 to effective Rt after the minimized intervention at time.

Probably equal to 25%? One can then, using the SEIR epidemiological models. Calculating the partial reduction of R will significantly flatten the curve to the desired level to avoid overpowering the health care system.

However, the calculation of R from bottom to top is very complicated because it requires the knowledge of many mechanical factors which are not easy to quantify.

For example, we do not know what rate COVID-19 is transmitted by large droplets compared to small aerosols. Only in the latter case will the advantages of the N95 gas mask over the surgical mask be fully realized! We also don’t know how far the social gap is to reduce R.

So let us consider when the authorities declared “the surgical mask is not working”.


COVID-19, like any virus, must attach to human cells using the key-lock principle. In which viruses present keys and lock cells complement keys to invade cells and copy.

For SARS-Cov-2 virus, the “Spike protein S” surface protein is the key key and it must fit the face lock protein on the host cell surface.

This cell surface enzyme usually protects the heart and lung function. ACE2 is expressed at a higher level in the elderly, in people with chronic heart failure or with pulmonary or systemic hypertension. Specific blood pressure medications are also a risk factor for progressing to ARDS and death in hypertension in COVID-19 fluid.

But mechanical stress-induced stress mechanisms may also increase ACE2’s understanding.

Surprisingly, ACE2 expression in the lungs is very low: it is limited to a few molecules per cell in alveolar cells (AT2 cells) deep in the lungs. But an article just published by the Human Cell Atlas Association (HCA) suggests that ACE2 is highly expressed in certain cell types of the inner nose!

Combining this fact with the above explanation of the mechanism:

The nasal expression of the ACE2 protein indicates that COVID-19 infects these cells. One can also infer that the transmission of the COVID-19 will occur mostly through coughing or sneezing. Including most of the liquid sprayed during coughing/sneezing and will fall into the throat.

Exactly where the key molecule for the virus is, allows attachment of the virus and invades the host cell. Apparently this transmission line can effectively blocked by simple physical barriers.

The manifestation of ACE in the nasal cavity is also a factor in surface transmission.

Therefore, hand washing is really necessary.

In fact, Wölfel et al. said that: the virus can easily be detected and isolated from nasal swabs. Unlike in the case of other airborne viral infections, such as SARS.

Compared to SARS in the case of COVID-19, the viral genome (RNA) appears earlier in the cotton swab and at a much higher concentration. So the detection is quite easily. In fact, the FDA only approves swabs for tests done from the front of the nose through self-collection, rather than deep in the palate.

Molecular analysis also showed that SARS-Cov2 virus was active and had multiplied in the palate, unlike other respiratory viruses living in deeper areas of the lungs.

Replication of the virus in the mucosa of the nose and throat may also explain the positive tests in the prodrome and passed on by healthy carriers. And probably the anesthetic seen in the early stages of COVID-19.

But this also means: avoiding large droplets so that they do not enter the lungs and possibly in the upper respiratory tract are also significant measures to prevent infection.

As a result, surgical masks, even your ski masks, scarves may be more protective than described by government officials to wearing a mask in general. N95 respirator masks may protect the skin less than it thinks. To be fair, CDC recommends the use of health care providers’ scarves as a last resort when masks are not available.

From a practical and social point of view, surgical or self-made masks, if handled properly, at worst will not cause injury. Or may help prevent infection. Be sure to throw away or wash after use without touching the outer surface.

These simple, inexpensive masks may be enough to help smooth the curve, perhaps a bit or significantly.


If not discriminated against wearing a mask, may have contributed to the prevention of COVID-19. Because the upper airway is the main site for SARS-Cov-2 to enter human tissue.

Wearing a simple mask has a barrier function that prevents large droplets from falling into the nose or throat.

For the time being: if we soon relax the social isolation due to political pressure to sustain the economy. Perhaps encouraging the wearing of masks for the community will be a good compromise between a complete closure and freedom is at full risk of reviving invisible enemies.

There is now a strong scientific basis for ending the surgical masks hysteria and proposing or even enforcing the widespread use of masks as in Asian countries.

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