Good day all.

Information about (simple) mask wearing (concerning covid19) is a complete mystery to me. On several official places it is not recommanded for a person without symptoms to wear a mask. For example:

https://youtu.be/Ded_AxFfJoQ (time 0:20)

or here:

https://www.ucsfhealth.org/education/should-i-wear-a-mask-to-protect-against-the-coronavirus

However no explanation is given - which makes me wonder (and even angry). I think everybody should weak a mask because:

• Many persons feel ashamed wearing it, even those with symptomps. If everybody wears it, they do not feel ashamed and wear it.

• As far as I know, one is (wrt covid19) contagious before developing symptomps. So if everybody wears the mask also these people do.

The two above points act as a collective protection.

• Simple mask certainly will lower "getting / spreading illness" probability. Of course the "holes" (in a simple mask) are too big to prevent completly virus to enter (or get out when coughing), but it lowers probability! Even if it lowers the transmission probability by e.g. 5%, it might be a lot. As hypothetical example: it might bring ratio from 1.02 to 0.97 and so stop the virus spread.

The videos are full of self-contradiction. In the same video

https://youtu.be/Ded_AxFfJoQ

time 0:50 the lady says I should wear a mask if I am in contact with an infected person... why if it is inefficient?

Question: What are reasons for not recommanding wearing a mask?

Information about (simple) mask wearing (concerning covid19) is a complete mystery to me. On several official places it is not recommended for a person without symptoms to wear a mask. For example:

https://youtu.be/Ded_AxFfJoQ (time 0:20)

or here:

https://www.ucsfhealth.org/education/should-i-wear-a-mask-to-protect-against-the-coronavirus

However no explanation is given - which makes me wonder (and even angry). I think everybody should wear a mask because:

• Many persons feel ashamed wearing it, even those with symptoms. If everybody wears it, they do not feel ashamed and wear it.

• As far as I know, one is (wrt covid19) contagious before developing symptoms. So if everybody wears the mask also these people do.

The two above points act as a collective protection.

• Simple mask certainly will lower "getting / spreading illness" probability. Of course the "holes" (in a simple mask) are too big to prevent completely virus to enter (or get out when coughing), but it lowers probability! Even if it lowers the transmission probability by e.g. 5%, it might be a lot. As a hypothetical example: it might reduce R0 from 1.02 to 0.97 and so stop the virus spread so fast.

The videos are full of self-contradiction. In the same video

https://youtu.be/Ded_AxFfJoQ

time 0:50 the lady says I should wear a mask if I am in contact with an infected person... why if it is inefficient?

Question: What are reasons for not recommending wearing a mask?

Good day all.

Information about (simple) mask wearing (concerning covid19) is a complete mystery to me. On several official places it is not recommanded for a person without symptoms to wear a mask. For example:

https://youtu.be/Ded_AxFfJoQ (time 0:20)

or here:

https://www.ucsfhealth.org/education/should-i-wear-a-mask-to-protect-against-the-coronavirus

However no explanation is given - which makes me wonder (and even angry). I think everybody should weak a mask because:

• Many persons feel ashamed wearing it, even those with symptomps. If everybody wears it, they do not feel ashamed and wear it.

• As far as I know, one is (wrt covid19) contagious before developing sympromps. So if everybody wears the mask also this people do.

The two above points act as a collective protection.

• Simple mask certainly will lower "getting / spreading illness" probability. Of course the "holes" (in a simple mask) are too big to prevent completly virus to enter (or get out when coughing), but it lowers probability! Even if it lowers the transmission probability for e.g. 5%, it might be a lot. As hypothetical example: it might bring ratio from 1.02 to 0.97 and so stop the virus spread.

The videos are full of self-contradiction. In the same video

https://youtu.be/Ded_AxFfJoQ

time 0:50 the lady says I should wear a mask if I am in contact with an infected person... why if it is inefficient?

Question: What are reasons for not recommanding wearing a mask?

Good day all.

Information about (simple) mask wearing (concerning covid19) is a complete mystery to me. On several official places it is not recommanded for a person without symptoms to wear a mask. For example:

https://youtu.be/Ded_AxFfJoQ (time 0:20)

or here:

https://www.ucsfhealth.org/education/should-i-wear-a-mask-to-protect-against-the-coronavirus

However no explanation is given - which makes me wonder (and even angry). I think everybody should weak a mask because:

• Many persons feel ashamed wearing it, even those with symptomps. If everybody wears it, they do not feel ashamed and wear it.

• As far as I know, one is (wrt covid19) contagious before developing symptomps. So if everybody wears the mask also these people do.

The two above points act as a collective protection.

• Simple mask certainly will lower "getting / spreading illness" probability. Of course the "holes" (in a simple mask) are too big to prevent completly virus to enter (or get out when coughing), but it lowers probability! Even if it lowers the transmission probability by e.g. 5%, it might be a lot. As hypothetical example: it might bring ratio from 1.02 to 0.97 and so stop the virus spread.

The videos are full of self-contradiction. In the same video

https://youtu.be/Ded_AxFfJoQ

time 0:50 the lady says I should wear a mask if I am in contact with an infected person... why if it is inefficient?

Question: What are reasons for not recommanding wearing a mask?