The Effectiveness of Wearing a Mask Against Covid-19

[BeautifulStranger]

This is critical... do you really know that asymptomatic people spread the virus in significant numbers....
Please show the data on asymptomatic transmission.
All I have seen are models... no real data.
I would love to see those studies.


---
All I have read is that the WHO said the data is hard to find and member countries have reported very little asymptomatic transmission. They said this in a June 5th paper and then a a few days later a spokesperson said it ... but then backtracked.

Then they backed tracked and said...

https://www.statnews.com/2020/06/09/who-comments-asymptomatic-spread-covid-19/



top World Health Organization official clarified on Tuesday that scientists have not determined yet how frequently people with asymptomatic cases of Covid-19 pass the disease on to others, a day after suggesting that such spread is “very rare.”

The clarification comes after the WHO’s original comments incited strong pushback from outside public health experts, who suggested the agency had erred, or at least miscommunicated, when it said people who didn’t show symptoms were unlikely to spread the virus.

Maria Van Kerkhove, the WHO’s technical lead on the Covid-19 pandemic, made it very clear Tuesday that the actual rates of asymptomatic transmission aren’t yet known.

Attached below is a letter to the editor of NEJM.org by several Japanese scientists using cruise ship infection data:

Natural History of Asymptomatic SARS-CoV-2 Infection

• 3 Citing Articles

TO THE EDITOR:

Information on the natural history of asymptomatic infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains scarce.1-3 The outbreak of coronavirus disease 2019 (Covid-19) on the cruise ship Diamond Princess led to 712 persons being infected with SARS-CoV-2 among the 3711 passengers and crew members, and 410 (58%) of these infected persons were asymptomatic at the time of testing (see the Supplementary Appendix, available with the full text of this letter at NEJM.org).4,5 Here, we report the natural history of asymptomatic SARS-CoV-2 infection in part of this cohort.

A total of 96 persons infected with SARS-CoV-2 who were asymptomatic at the time of testing, along with their 32 cabinmates who tested negative on the ship, were transferred from the Diamond Princess to a hospital in central Japan between February 19 and February 26 for continued observation. Clinical signs and symptoms of Covid-19 subsequently developed in 11 of these 96 persons, a median of 4 days (interquartile range, 3 to 5; range, 3 to 7) after the first positive polymerase-chain-reaction (PCR) test, which meant that they had been presymptomatic rather than asymptomatic. The risk of being presymptomatic increased with increasing age (odds ratio for being presymptomatic with each 1-year increase in age, 1.08; 95% confidence interval [CI], 1.01 to 1.16). Eight of 32 cabinmates with a negative PCR test on the ship had a positive PCR test within 72 hours after arrival in the hospital but remained asymptomatic. In total, data on 90 persons with asymptomatic SARS-CoV-2 infection, defined as persons who were asymptomatic at the time of the positive PCR test and remained so until the resolution of infection (as determined by two consecutive negative PCR tests), were available for analysis (Fig. S1 in the Supplementary Appendix).

Figure 1.

Crossing-Point Values in RT-PCR Testing of Asymptomatic Persons with SARS-CoV-2 Infection.
The group of persons with asymptomatic SARS-CoV-2 infection consisted of 58 passengers and 32 crew members, with median age of 59.5 years (interquartile range, 36 to 68; range, 9 to 77). A total of 24 of these persons (27%) had coexisting medical conditions, including hypertension (in 20%) and diabetes (9%). The first PCR test at the hospital was performed a mean of 6 days after the initial positive PCR test on the ship. The median number of days between the first positive PCR test (either on the ship or at the hospital) and the first of the two serial negative PCR tests was 9 days (interquartile range, 6 to 11; range, 3 to 21), and the cumulative percentages of persons with resolution of infection 8 and 15 days after the first positive PCR test were 48% and 90%, respectively. The risk of delayed resolution of infection increased with increasing age (mean delay in resolution for an increase in age from 36 to 68 years, 4.41 days; 95% CI, 2.28 to 6.53) (Figure 1).

In this cohort, the majority of asymptomatically infected persons remained asymptomatic throughout the course of the infection. The time to the resolution of infection increased with increasing age.

Aki Sakurai, M.D.
Toshiharu Sasaki, M.D.
Fujita Health University, Aichi, Japan

Shigeo Kato, Pharm.B.
Ministry of Health, Labor, and Welfare Nagoya Quarantine Station, Aichi, Japan

Masamichi Hayashi, M.D., Ph.D.
Sei-ichiro Tsuzuki, M.D.
Fujita Health University, Aichi, Japan

Takuma Ishihara, M.S.
Gifu University Hospital, Gifu, Japan

Mitsunaga Iwata, M.D., Ph.D.
Zenichi Morise, M.D., Ph.D.
Yohei Doi, M.D., Ph.D.
Fujita Health University, Aichi, Japan
yoheidoi@fujita-hu.ac.jp

Disclosure forms provided by the authors are available with the full text of this letter at NEJM.org.

This letter was published on June 12, 2020, at NEJM.org.

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Supplementary Material
Supplementary Appendix PDF 1693KB
Disclosure Forms PDF 387KB

Citing Articles (3)

1. S Saurabh, R Kumar, M K Gupta, P Bhardwaj, V L Nag, M K Garg, S Misra. (2020) Prolonged persistence of SARS-CoV-2 in the upper respiratory tract of asymptomatic infected individuals. QJM: An International Journal of Medicine 26.
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2. Alexander J Keeley, Cariad M Evans, Thushan I de Silva. (2020) Asymptomatic SARS-CoV-2 infection: the tip or the iceberg?. Thorax 25, thoraxjnl-2020-215337.
   • Crossref . opens in new tab
   
   
   
3. Dominic A. Fitzgerald, Gary W.K. Wong. (2020) COVID-19: A tale of two pandemics across the Asia Pacific region. Paediatric Respiratory Reviews.
   • Crossref

https://www.nejm.org/doi/full/10.1056/NEJMc2013020?query=featured_coronavirus



Edit: So it is important to distinguish between presymptomatic and asymptomatic infections. The critical metric is the ability of an asymptomatic patient to infect others. I will look for more letters on this subject.

 

[BeautifulStranger]

This is critical... do you really know that asymptomatic people spread the virus in significant numbers....
Please show the data on asymptomatic transmission.
All I have seen are models... no real data.
I would love to see those studies.


---
All I have read is that the WHO said the data is hard to find and member countries have reported very little asymptomatic transmission. They said this in a June 5th paper and then a a few days later a spokesperson said it ... but then backtracked.

Then they backed tracked and said...

https://www.statnews.com/2020/06/09/who-comments-asymptomatic-spread-covid-19/



top World Health Organization official clarified on Tuesday that scientists have not determined yet how frequently people with asymptomatic cases of Covid-19 pass the disease on to others, a day after suggesting that such spread is “very rare.”

The clarification comes after the WHO’s original comments incited strong pushback from outside public health experts, who suggested the agency had erred, or at least miscommunicated, when it said people who didn’t show symptoms were unlikely to spread the virus.

Maria Van Kerkhove, the WHO’s technical lead on the Covid-19 pandemic, made it very clear Tuesday that the actual rates of asymptomatic transmission aren’t yet known.

Attached below is a letter to the editor at NEJM.org by German doctors concerning Asymptomatic infection:

CORRESPONDENCE

Transmission of 2019-nCoV Infection from an Asymptomatic Contact in Germany

• 682 Citing Articles

TO THE EDITOR:
The novel coronavirus (2019-nCoV) from Wuhan is currently causing concern in the medical community as the virus is spreading around the world.1 Since identification of the virus in late December 2019, the number of cases from China that have been imported into other countries is on the rise, and the epidemiologic picture is changing on a daily basis. We are reporting a case of 2019-nCoV infection acquired outside Asia in which transmission appears to have occurred during the incubation period in the index patient.

A 33-year-old otherwise healthy German businessman (Patient 1) became ill with a sore throat, chills, and myalgias on January 24, 2020. The following day, a fever of 39.1°C (102.4°F) developed, along with a productive cough. By the evening of the next day, he started feeling better and went back to work on January 27.

Figure 1.

Timeline of Exposure to Index Patient with Asymptomatic 2019-CoV Infection in Germany.
Before the onset of symptoms, he had attended meetings with a Chinese business partner at his company near Munich on January 20 and 21. The business partner, a Shanghai resident, had visited Germany between January 19 and 22. During her stay, she had been well with no signs or symptoms of infection but had become ill on her flight back to China, where she tested positive for 2019-nCoV on January 26 (index patient in Figure 1) (see Supplementary Appendix, available at NEJM.org, for details on the timeline of symptom development leading to hospitalization).

On January 27, she informed the company about her illness. Contact tracing was started, and the above-mentioned colleague was sent to the Division of Infectious Diseases and Tropical Medicine in Munich for further assessment. At presentation, he was afebrile and well. He reported no previous or chronic illnesses and had no history of foreign travel within 14 days before the onset of symptoms. Two nasopharyngeal swabs and one sputum sample were obtained and were found to be positive for 2019-nCoV on quantitative reverse-transcriptase–polymerase-chain-reaction (qRT-PCR) assay.2 Follow-up qRT-PCR assay revealed a high viral load of 108 copies per milliliter in his sputum during the following days, with the last available result on January 29.

On January 28, three additional employees at the company tested positive for 2019-nCoV (Patients 2 through 4 in Figure 1). Of these patients, only Patient 2 had contact with the index patient; the other two patients had contact only with Patient 1. In accordance with the health authorities, all the patients with confirmed 2019-nCoV infection were admitted to a Munich infectious diseases unit for clinical monitoring and isolation. So far, none of the four confirmed patients show signs of severe clinical illness.

This case of 2019-nCoV infection was diagnosed in Germany and transmitted outside Asia. However, it is notable that the infection appears to have been transmitted during the incubation period of the index patient, in whom the illness was brief and nonspecific.3

The fact that asymptomatic persons are potential sources of 2019-nCoV infection may warrant a reassessment of transmission dynamics of the current outbreak. In this context, the detection of 2019-nCoV and a high sputum viral load in a convalescent patient (Patient 1) arouse concern about prolonged shedding of 2019-nCoV after recovery. Yet, the viability of 2019-nCoV detected on qRT-PCR in this patient remains to be proved by means of viral culture.

Despite these concerns, all four patients who were seen in Munich have had mild cases and were hospitalized primarily for public health purposes. Since hospital capacities are limited — in particular, given the concurrent peak of the influenza season in the northern hemisphere — research is needed to determine whether such patients can be treated with appropriate guidance and oversight outside the hospital.

Camilla Rothe, M.D.
Mirjam Schunk, M.D.
Peter Sothmann, M.D.
Gisela Bretzel, M.D.
Guenter Froeschl, M.D.
Claudia Wallrauch, M.D.
Thorbjörn Zimmer, M.D.
Verena Thiel, M.D.
Christian Janke, M.D.
University Hospital LMU Munich, Munich, Germany
rothe@lrz.uni-muenchen.de

Wolfgang Guggemos, M.D.
Michael Seilmaier, M.D.
Klinikum München-Schwabing, Munich, Germany

Christian Drosten, M.D.
Charité Universitätsmedizin Berlin, Berlin, Germany

Patrick Vollmar, M.D.
Katrin Zwirglmaier, Ph.D.
Sabine Zange, M.D.
Roman Wölfel, M.D.
Bundeswehr Institute of Microbiology, Munich, Germany

Michael Hoelscher, M.D., Ph.D.
University Hospital LMU Munich, Munich, Germany

Disclosure forms provided by the authors are available with the full text of this letter at NEJM.org.

This letter was published on January 30, 2020, and updated on February 6, 2020, at NEJM.org.

https://www.nejm.org/doi/full/10.1056/NEJMc2001468?query=featured_coronavirus

 

[FortuneTeller]

This illustration is actually close to the reality.

View attachment 234959

IF a mask stops the virus then only those who are paranoid of getting it should be the ones who wear masks. They can wear them for the rest of their lives. They will enjoy the certainty of never getting sick in their minds. The rest of us will become immune by being exposed to it.

 

[easymon1]

Sneezin' Honkey

NHL Game

 

[Tsing Tao]

Wouldn't that depend on the windiness, crowd size, personal risk factors, and closeness to people outside of your household?

I suppose if people were wall to wall, shoulder to shoulder they might have a use. But people are nowhere near each other. And the fact that the sun's ultraviolet light is on everything, killing all germs, bacteria, viruses...I guess I just don't see the point.

 

[userque]

I suppose if people were wall to wall, shoulder to shoulder they might have a use. But people are nowhere near each other. And the fact that the sun's ultraviolet light is on everything, killing all germs, bacteria, viruses...I guess I just don't see the point.

Are you suggesting that people on beaches are too far apart for the virus to travel from person to person via the air?

And that even if the virus did travel from person to person, the sunlight would kill it before it made it to the next person?

 

[Tsing Tao]

Are you suggesting that people on beaches are too far apart for the virus to travel from person to person via the air?

And that even if the virus did travel from person to person, the sunlight would kill it before it made it to the next person?

I'm suggesting that masks are quite ineffective (overkill) at the beach for a number of reasons. That is my opinion.

But it is a free country and people can wear whatever they want. Most people seem to agree with me, at the beach,.

 

[Wallet]

I'm suggesting that masks are quite ineffective (overkill) at the beach for a number of reasons.

And while driving by yourself.

 

[userque]

I'm suggesting that masks are quite ineffective (overkill) at the beach for a number of reasons. That is my opinion.

But it is a free country and people can wear whatever they want. Most - if not all - people seem to agree with me, at the beach,.

You stated certain conditions:

"I suppose if people were wall to wall, shoulder to shoulder they might have a use. But people are nowhere near each other."

So I asked, "Are you suggesting that people on beaches are too far apart for the virus to travel from person to person via the air?"

Are you suggesting that that--or something else--explains how you believe that masks would only help in a shoulder-to-shoulder crowd.

Why don't you believe that masks will help if people were, say, 4 feet apart?

Your above reply seems to disregard your prior specifics and speaks generally, but my questions to you are regarding your specific allegations.

You also stated:

"And the fact that the sun's ultraviolet light is on everything, killing all germs, bacteria, viruses...I guess I just don't see the point."

So I asked if you were suggesting that, "... even if the virus did travel from person to person, the sunlight would kill it before it made it to the next person?"

I'm wanting to clearly understand if that's what you're suggesting.

I have not agreed or disagreed with you. Before I draw a conclusion, I like to first fully understand the assertion.

If I can understand the basis for your opinion, maybe I can learn something new.

 

[Tsing Tao]

You stated certain conditions:

"I suppose if people were wall to wall, shoulder to shoulder they might have a use. But people are nowhere near each other."

So I asked, "Are you suggesting that people on beaches are too far apart for the virus to travel from person to person via the air?"

Are you suggesting that that--or something else--explains how you believe that masks would only help in a shoulder-to-shoulder crowd.

Why don't you believe that masks will help if people were, say, 4 feet apart?

Your above reply seems to disregard your prior specifics and speaks generally, but my questions to you are regarding your specific allegations.

You also stated:

"And the fact that the sun's ultraviolet light is on everything, killing all germs, bacteria, viruses...I guess I just don't see the point."

So I asked if you were suggesting that, "... even if the virus did travel from person to person, the sunlight would kill it before it made it to the next person?"

I'm wanting to clearly understand if that's what you're suggesting.

I have not agreed or disagreed with you. Before I draw a conclusion, I like to first fully understand the assertion.

If I can understand the basis for your opinion, maybe I can learn something new.

This began with me noting that I saw a few (like 3) people on the beach last weekend with a mask on. I thought this odd. They were sitting on a blanket, no one was around them. The beach was relatively uncrowded. For example, my friends and family had a tent set up and there were probably 20 or 30 feet between us and the closest beach goers. This was relatively standard as far as spacing goes between people that day.

There was no real breeze (or it was very light), and it was hot as hell (Florida summer day).

Given all of these factors, I do not see how wearing a mask added any real protection for the discomfort wearing a mask on a hot summer day at the beach gives one. So I would not have worn one. But, as a supporter of individual rights, I have no issue with others wearing them either. If someone wanted to come to the beach wearing a total HazMat suit or a space suit or a gorilla suit, they should do so, as that is personal choice.

This is what I am stating.