Read on Twitter
Some weeks ago, I was talking about masks again. This topic is very controversial, and people tend to oversimplify it. https://twitter.com/anderws/status/1277963962034708481?s=20
Today, France has made masks mandatory.
I saw the following picture in my timeline several times. It is about the barrier effect (with some random numbers). I wish everything were so simple, but it is not. It removes a lot of factors.
I saw the following picture in my timeline several times. It is about the barrier effect (with some random numbers). I wish everything were so simple, but it is not. It removes a lot of factors.
1) We have a lot of cases where masks are mandatory (ex: health care settings, food factories...).
2) We have cases where masks have a lot of adherence from the beginning of the pandemic (ex: Japan reported 510 new cases).
2) We have cases where masks have a lot of adherence from the beginning of the pandemic (ex: Japan reported 510 new cases).
3) We have cases where masks were advised a long time ago (ex: South Africa reported +10.000 new cases), and masks were recommended in April. https://sacoronavirus.co.za/2020/04/10/dr-zweli-mkhize-recommends-the-widespread-use-of-cloth-masks/
When the physical distance is applied (ex: lockdown), cases go down, when a lockdown is removed, and masks are mandatory, new cases start to go up again in many countries.
Probably, because we are using masks where transmission is not common (outdoors), and we don't use masks where transmission is high (while eating/drinking, own home - household transmission...).
Studies must go beyond the barrier effect and check the context use and human behavior. We need to know where transmission happens and if the masks can be used in that context.
It is useless if the transmission occurs during lunch breaks where masks cannot be used.
It is useless if the transmission occurs during lunch breaks where masks cannot be used.
This kind of cluster analysis is very useful.
Clusters of Coronavirus Disease in Communities, Japan, January–April 2020 https://wwwnc.cdc.gov/eid/article/26/9/20-2272_article
Clusters of Coronavirus Disease in Communities, Japan, January–April 2020 https://wwwnc.cdc.gov/eid/article/26/9/20-2272_article
“We found that healthcare facilities, such as hospitals, and care facilities, such as nursing homes, were the primary sources of clusters, some of which had >100 cases.”
Masks are used, however...
Masks are used, however...
“We noted many COVID-19 clusters were associated with heavy breathing in close proximity, such as singing at karaoke parties, cheering at clubs, having conversations in bars, and exercising in gymnasiums.”
Masks are not being used... (or cannot)
Masks are not being used... (or cannot)
WHO Media Briefing: Just now, a question about masks from a Chinese Journalist and another about what South Africa didn’t do well when they applied all recommended measures for a long time (including mask use).
Singapore:
Community Cases: 2,146
Dorm Residents: 45,944
TOTAL: 48,744
Do you use your mask when you are in your home? When you sleep? Probably, you don’t.
Would masks had reduced most of the cases in Singapore related to dorm residents?
https://www.moh.gov.sg/docs/librariesprovider5/2019-ncov/situation-report---22-jul-2020.pdf
Community Cases: 2,146
Dorm Residents: 45,944
TOTAL: 48,744
Do you use your mask when you are in your home? When you sleep? Probably, you don’t.
Would masks had reduced most of the cases in Singapore related to dorm residents?
https://www.moh.gov.sg/docs/librariesprovider5/2019-ncov/situation-report---22-jul-2020.pdf
We have seen cases in Spain too, related to a refugee center and fruit pickers migrants, who lived without enough physical distance. https://english.elpais.com/society/2020-06-26/covid-19-outbreaks-test-spains-ability-to-prevent-transmission.html
And Germany, where a single outbreak created +2000 cases in a meat factory.
According to some sources (unconfirmed), workers were wearing masks.
Likely infection causes:
- Mask misuse
- Household infection (no mask)
- During lunch (no mask) https://www.bbc.com/news/world-europe-53177628
According to some sources (unconfirmed), workers were wearing masks.
Likely infection causes:
- Mask misuse
- Household infection (no mask)
- During lunch (no mask) https://www.bbc.com/news/world-europe-53177628
Recently, some media has highlighted this article
“Absence of Apparent Transmission of SARS-CoV-2 from Two Stylists After Exposure at a Hair Salon with a Universal Face Covering Policy — Springfield, Missouri, May 2020”
Conclusions are very controversial https://www.cdc.gov/mmwr/volumes/69/wr/mm6928e2.htm
“Absence of Apparent Transmission of SARS-CoV-2 from Two Stylists After Exposure at a Hair Salon with a Universal Face Covering Policy — Springfield, Missouri, May 2020”
Conclusions are very controversial https://www.cdc.gov/mmwr/volumes/69/wr/mm6928e2.htm
Hairstylists were positive and they didn’t transmit the virus to their clients because they cover their mouths, according to the article.
However, Stylist B “who had been exposed to stylist A, developed respiratory symptoms” “the two stylists interacted while neither was masked”
However, Stylist B “who had been exposed to stylist A, developed respiratory symptoms” “the two stylists interacted while neither was masked”
That article ignores:
- Time (How long did they spend with their hairstylists?)
- Interactions (were they talking?)
- Direction (were clients facing hairstylists?)
- Environment (Good ventilation?)
Risks were very low for clients.
- Time (How long did they spend with their hairstylists?)
- Interactions (were they talking?)
- Direction (were clients facing hairstylists?)
- Environment (Good ventilation?)
Risks were very low for clients.
However, hairstylists infected each other, and stylist A family was positive (household transmission):
- husband
- her daughter
- son-in-law, and their roommate
- husband
- her daughter
- son-in-law, and their roommate
It is not about if masks can block a pathogen, it is about if we are using the masks where transmission happens and if physical distance or other NPIs are more effective.
Oversimplification:
Condoms are a barrier that protects from many sexual diseases.
You can use a condom 24 hours (while walking, eating, watching Netflix...) and don’t use it because you are with your ”loyal” partner.
Condoms are a barrier that protects from many sexual diseases.
You can use a condom 24 hours (while walking, eating, watching Netflix...) and don’t use it because you are with your ”loyal” partner.
A new study about masks, again about the barrier effect... Nothing new https://twitter.com/CNN/status/1286544481454628864
Covid Success Story Stands Out for Its Controversial Mask Policy
“All these countries recommending face masks haven’t made their decisions based on new studies,” Bundgaard said in an interview in Copenhagen. https://www.bloomberg.com/news/articles/2020-07-26/u-s-hot-spots-get-reprieve-from-climbing-cases-virus-update
“All these countries recommending face masks haven’t made their decisions based on new studies,” Bundgaard said in an interview in Copenhagen. https://www.bloomberg.com/news/articles/2020-07-26/u-s-hot-spots-get-reprieve-from-climbing-cases-virus-update
Some people DM me and asked me this mask.
It is a reusable mask, 2 cotton layers, and space for PM2.5 filters. This model (“We are in this together”) is sold out at this moment. https://twitter.com/anderws/status/1277963962034708481
It is a reusable mask, 2 cotton layers, and space for PM2.5 filters. This model (“We are in this together”) is sold out at this moment. https://twitter.com/anderws/status/1277963962034708481
June:
Some people say... “Countries that have contained major COVID-19 outbreaks have close to 100% mask usage”
August:
That statement wasn't science-based as usual. Lockdowns (aka physical distance) was one reason. The other was related to the prevalence of the virus.
Some people say... “Countries that have contained major COVID-19 outbreaks have close to 100% mask usage”
August:
That statement wasn't science-based as usual. Lockdowns (aka physical distance) was one reason. The other was related to the prevalence of the virus.
How many people need to wear masks to reduce community transmission?
- ”80 percent of the population wearing masks would do more to reduce COVID-19 spread than a strict lockdown”
Where it is mandatory, cases are increasing, where it is not, it’s decreasing (Sweeden, Denmark...)
- ”80 percent of the population wearing masks would do more to reduce COVID-19 spread than a strict lockdown”
Where it is mandatory, cases are increasing, where it is not, it’s decreasing (Sweeden, Denmark...)
When some people exclude human behavior, studies are flawed.
You don't sleep with masks; you don't use masks in your home with your family, you don't eat or drink with masks; you don't use a mask correctly at all times...
You don't sleep with masks; you don't use masks in your home with your family, you don't eat or drink with masks; you don't use a mask correctly at all times...
Physical distance can protect you at all times
”While people have continued to wear masks throughout the pandemic, the current infections have largely occurred in situations where face coverings aren’t typically worn, like group dining and drinking events.”
https://www.bloomberg.com/news/articles/2020-07-31/japan-acted-like-the-virus-had-gone-now-it-s-spread-everywhere
https://www.bloomberg.com/news/articles/2020-07-31/japan-acted-like-the-virus-had-gone-now-it-s-spread-everywhere
Some media are starting to discover that masks aren't a panacea... Endless.
I said many times we need studies beyond the barrier effect of the mask.
Currently, there are many measures, and we don't know which one is really working or if all of them are working together.
Is it physical distance or a mask? https://twitter.com/anderws/status/1246130732982042626
Currently, there are many measures, and we don't know which one is really working or if all of them are working together.
Is it physical distance or a mask? https://twitter.com/anderws/status/1246130732982042626
”The fallacy of the single cause, is a fallacy of questionable cause that occurs when it is assumed that there is a single, simple cause of an outcome when in reality it may have been caused by a number of only jointly sufficient causes.” https://twitter.com/anderws/status/1246133186352025600
Someone asked WHO if there is a correlation between wearing a mask and countries incidence.
WHO didn't reply to that question. WHO says, "wear a mask when you cannot keep your distance."
That is the most crucial message, distance.
WHO didn't reply to that question. WHO says, "wear a mask when you cannot keep your distance."
That is the most crucial message, distance.
Some people are starting to realize that masks are not going to stop the virus and It was wishful thinking.
There are a lot of studies related to face masks in the last decades, especially in the influenza context.
We are ignoring all of them.
We are ignoring all of them.
Now, we have new studies (beyond the barrier effect):
“We did not find evidence that surgical-type face masks are effective in reducing laboratory-confirmed influenza transmission”
https://wwwnc.cdc.gov/eid/article/26/5/19-0994_article
“We did not find evidence that surgical-type face masks are effective in reducing laboratory-confirmed influenza transmission”
https://wwwnc.cdc.gov/eid/article/26/5/19-0994_article
These studies are based on influenza, so there are some limitations.
More studies are needed beyond the barrier effect. Context, culture, real use..
By the way, this study was supported by the WHO and the University of Hong Kong.
More studies are needed beyond the barrier effect. Context, culture, real use..
By the way, this study was supported by the WHO and the University of Hong Kong.
WHO recommendations in October 2019, based on the evidence at that moment.
“Additional high-quality RCTs of the efficacy of face masks against laboratory-confirmed influenza would be valuable.”
https://www.who.int/influenza/publications/public_health_measures/publication/en/
“Additional high-quality RCTs of the efficacy of face masks against laboratory-confirmed influenza would be valuable.”
https://www.who.int/influenza/publications/public_health_measures/publication/en/
Spain is leading the face mask use.
It is also leading new diagnosed cases number, which is increasing in all EU countries where masks are mandatory.
It is also leading new diagnosed cases number, which is increasing in all EU countries where masks are mandatory.
France made masks mandatory 3 weeks ago...
According to many people, cases should be reduced...
What do you think is the situation now? https://twitter.com/anderws/status/1285203690421399553
According to many people, cases should be reduced...
What do you think is the situation now? https://twitter.com/anderws/status/1285203690421399553
”France reported more than 2,500 new COVID-19 infections for the second day in a row on Thursday, levels last seen in mid-April“ https://www.reuters.com/article/us-health-coronavirus-france-casualties-idUSKCN2592GW
“Face masks essential to contain pandemic, Chinese doctor” April 2020
More masks than ever, more cases than ever too https://www.efe.com/efe/english/world/face-masks-essential-to-contain-pandemic-chinese-doctor/50000262-4218914
More masks than ever, more cases than ever too https://www.efe.com/efe/english/world/face-masks-essential-to-contain-pandemic-chinese-doctor/50000262-4218914
About the former news, It appears in Spanish media (EL PAIS and ABC) more than other places.
The Press was invited to an interview in Wuhan in April and “spread” Chinese mainland message to their countries.
The Press was invited to an interview in Wuhan in April and “spread” Chinese mainland message to their countries.
“Not using them is stupid” Wang Xinghuan
Results in English: https://www.google.com/search?q=%22stupid%22+%22Wang+Xinghuan%22
Results in Spanish: https://www.google.com/search?hl=en&q=%22estupido%22%20%22Wang%20Xinghuan%22
Results in English: https://www.google.com/search?q=%22stupid%22+%22Wang+Xinghuan%22
Results in Spanish: https://www.google.com/search?hl=en&q=%22estupido%22%20%22Wang%20Xinghuan%22
“The big mistake in the U.S. and Europe, in my opinion, is that people aren’t wearing masks.”
George Gao, director-general of the Chinese Center for Disease Control and Prevention (CDC)
Masks suppose to solve everything around the world...
https://www.sciencemag.org/news/2020/03/not-wearing-masks-protect-against-coronavirus-big-mistake-top-chinese-scientist-says
George Gao, director-general of the Chinese Center for Disease Control and Prevention (CDC)
Masks suppose to solve everything around the world...
https://www.sciencemag.org/news/2020/03/not-wearing-masks-protect-against-coronavirus-big-mistake-top-chinese-scientist-says
By the way, this thread is not against masks; it is against misleading statements, wrong correlations, wrong headlines, bad science...
Goldman Sachs in June…
“We find that face masks are associated with significantly better coronavirus outcomes.”
“it seems to reflect a largely causal impact of masks rather than correlation with other factors”
https://www.goldmansachs.com/insights/pages/face-masks-and-gdp.html
“We find that face masks are associated with significantly better coronavirus outcomes.”
“it seems to reflect a largely causal impact of masks rather than correlation with other factors”
https://www.goldmansachs.com/insights/pages/face-masks-and-gdp.html
In the meantime, we ignore a lot of studies:
While there is some experimental evidence that masks should be able to reduce infectiousness under controlled conditions, there is less evidence on whether this translates to effectiveness in natural settings.
https://www.cambridge.org/core/journals/epidemiology-and-infection/article/face-masks-to-prevent-transmission-of-influenza-virus-a-systematic-review/64D368496EBDE0AFCC6639CCC9D8BC05/core-reader?fbclid=IwAR2vEwdcNhO22eXmWlVhuuueib74A9VnXsmyL1OhhPOJzZRKd_uaDJnH2hA
While there is some experimental evidence that masks should be able to reduce infectiousness under controlled conditions, there is less evidence on whether this translates to effectiveness in natural settings.
https://www.cambridge.org/core/journals/epidemiology-and-infection/article/face-masks-to-prevent-transmission-of-influenza-virus-a-systematic-review/64D368496EBDE0AFCC6639CCC9D8BC05/core-reader?fbclid=IwAR2vEwdcNhO22eXmWlVhuuueib74A9VnXsmyL1OhhPOJzZRKd_uaDJnH2hA
It was a Hong Kong University review of many different studies about masks in real situations.
However, we need to analyze these data. Flu cases went down in several regions.
Why did the Flu goes down, but COVID didn’t?
Why did the Flu goes down, but COVID didn’t?
We have seen that in Taiwan too. We need more comprehensive studies and fewer egos. We still don’t know what works. Many knowledge gaps. https://twitter.com/anderws/status/1284150566432759808?s=20
This article says Starbucks ”Employees avoided infection, while 27 visitors got coronavirus” and many people are saying these supports masks protection, however, IMHO proves transmission happens when masks can not be used (drinking, eating, sleeping…). https://www.bloomberg.com/news/articles/2020-08-25/this-starbucks-in-south-korea-became-a-beacon-for-mask-wearing
Influenza went down in HK, too, because of all NPI (non-pharmaceutical interventions) applied for the novel coronavirus.
https://www.thelancet.com/journals/lanpub/article/PIIS2468-2667(20)30090-6/fulltext
https://www.thelancet.com/journals/lanpub/article/PIIS2468-2667(20)30090-6/fulltext
Flu has disappeared this season. We are expecting the same for the northern hemisphere if travel restrictions exist.
I wonder when people will admit that masks aren’t working as expected/announced. It should be the ultimate solution. Learn from Japan, South Korea, Taiwan… Sure.
Everything is much more complicated.
Everything is much more complicated.
By the way, Taiwan recommended that healthy students do NOT need to wear masks when the WHO declared the PHEIC.
Wear a mask only if you are sick or going to the hospital.
The same recommendations were in place worldwide at that moment.
https://www.cdc.gov.tw/En/Bulletin/Detail/fuxYlhrqkcT5drFreHzhAg?typeid=158
Wear a mask only if you are sick or going to the hospital.
The same recommendations were in place worldwide at that moment.
https://www.cdc.gov.tw/En/Bulletin/Detail/fuxYlhrqkcT5drFreHzhAg?typeid=158
Asia Vs. Africa
Maybe, we have lessons to learn from countries in Africa that combat many epidemics in the last years.
Maybe, we have lessons to learn from countries in Africa that combat many epidemics in the last years.
Carlos III Institute of Health (Spain) published about masks.
- Masks use doesn’t have enough evidence at this moment
- Masks policies should be more flexible
The last paragraph about narrative changes and scientific evidence is very interesting.
https://www.gacetasanitaria.org/es-face-masks-in-general-healthy-avance-S0213911120301990
- Masks use doesn’t have enough evidence at this moment
- Masks policies should be more flexible
The last paragraph about narrative changes and scientific evidence is very interesting.
https://www.gacetasanitaria.org/es-face-masks-in-general-healthy-avance-S0213911120301990
Many experts (aka give me a minute of popularity) keep warning about “winter” and “flu”, but we see flu nowhere.
Cambodia is the only country with influenza A(H3N2) outbreaks at this moment. By the way, Cambodia has not Covid at this moment.
https://www.who.int/influenza/surveillance_monitoring/updates/latest_update_GIP_surveillance/en/
https://www.who.int/influenza/surveillance_monitoring/updates/latest_update_GIP_surveillance/en/
If influenza virus doesn’t disseaper, it is going to be hard to create vaccines for the next season, because very few samples, and it could be an issue when travel restrictions are cleared.
It seems travel restrictions are the main reason for these very low levels of influenza worldwide.
Chains of transmission couldn’t travel between hemispheres. If masks were a (partly) reason, we should study why it worked for the Flu, but it didn’t work for COVID.
Chains of transmission couldn’t travel between hemispheres. If masks were a (partly) reason, we should study why it worked for the Flu, but it didn’t work for COVID.
Do you remember this graph? It was everywhere on Twitter last March. Masks were the ultimate, best, and the only tool to beat this coronavirus.
I tweeted another picture in April to try to explain the bias of seeing cause in correlation.
I tweeted another picture in April to try to explain the bias of seeing cause in correlation.
I still see an oversimplification in very complex topics. If it were so easy, It wouldn't be a pandemic. https://twitter.com/anderws/status/1246130732982042626
France reported +80.000 cases the last day. You probably remember this picture from July, when masks were starting to be mandatory there.
I tweeted about these random numbers at that moment.
https://twitter.com/anderws/status/1285203690421399553
I tweeted about these random numbers at that moment.
https://twitter.com/anderws/status/1285203690421399553
Back to the flu topic.
There is no flu yet.
There is no flu yet.
I mentioned this topic with the Taiwan CDC data in July.
In the meantime, many media and their experts (who never check data or evidence) have been talking about the combination of flu season with the coronavirus. https://twitter.com/anderws/status/1284150566432759808
In the meantime, many media and their experts (who never check data or evidence) have been talking about the combination of flu season with the coronavirus. https://twitter.com/anderws/status/1284150566432759808
Later data confirmed a much lower flu in the southern hemisphere… But many people were ignoring these insights again. https://twitter.com/anderws/status/1296431245883330561
More data was coming, but people prefer to ignore the evidence (well, i think they prefer yellow press more than read data)
I don’t know what will happen at the end, but can we go with the evidence & real science first? https://twitter.com/anderws/status/1304715490045112320
I don’t know what will happen at the end, but can we go with the evidence & real science first? https://twitter.com/anderws/status/1304715490045112320
After some delay, the most comprehensive study about masks has been published (finally!):
- It is randomized controlled trial
- Masks did not reduce the SARS-CoV-2 infection (…)
- lesser degrees of self-protection
https://www.acpjournals.org/doi/10.7326/M20-6817
- It is randomized controlled trial
- Masks did not reduce the SARS-CoV-2 infection (…)
- lesser degrees of self-protection
https://www.acpjournals.org/doi/10.7326/M20-6817
This study has had a lot of pressure, but It is finally published.
It is not about the barrier effect, it is about using the mask in the real life.
Anyway, this study cannot reply to all the questions, and I hope we can get more studies like this one.
It is not about the barrier effect, it is about using the mask in the real life.
Anyway, this study cannot reply to all the questions, and I hope we can get more studies like this one.
In the meantime, some studies about masks are withdrawal by their authors (and it is not the first time).
The bias of seeing cause in correlation. Very common nowadays.
https://www.medrxiv.org/content/10.1101/2020.10.21.20208728v2
The bias of seeing cause in correlation. Very common nowadays.
https://www.medrxiv.org/content/10.1101/2020.10.21.20208728v2
I think it could be useful for people to read some arguments against to the DANMASK19 study. https://twitter.com/trishgreenhalgh/status/1329163949732933633
Among many arguments are several modeling studies.
(Btw, modeling studies have been failed during all the pandemic). https://twitter.com/trishgreenhalgh/status/1329164767672627200
(Btw, modeling studies have been failed during all the pandemic). https://twitter.com/trishgreenhalgh/status/1329164767672627200
I found this online.
Correlation does not imply causation
Correlation does not imply causation
This long is very long, and you could miss some old tweets. We still don’t know which measures are the best because we are applying many simultaneously. https://twitter.com/anderws/status/1290141007019831296
And this thread is not against masks (I used it before this pandemic and I use it everyday now).
It is against misinformation. https://twitter.com/anderws/status/1285210315727278080
It is against misinformation. https://twitter.com/anderws/status/1285210315727278080
