Gene threw me a curve ball starting high and inside and breaking down and away right into the strike zone. A complete answer would require my own PhD dissertation, and my short answer required several hours of analysis and involved several emails from other chatlisters. I am delighted to be asked by Gene for my opinion, and equally delighted that many others were interested and willing to share both their opinions and insights and information. I encourage them to send their emails on to the Chatlist. I know this will be too long for some, but I have appended a bibliography of quotes from the same article Gene quoted in order to enlarge upon my short answer.
The Original Post from Gene:
Doc –
Since you posted on the Chatham Chatlist about wearing masks, I’d love
to get your analysis and opinion on an article published in a CDC.GOV journal (dated May 2020 but was released Feb. 6) that reviews trials of masks and hand washing against influenza and finds that –
“We did not find evidence of a major effect of hand hygiene on
laboratory-confirmed influenza virus transmission”
“We did not find evidence that surgical-type face masks are effective in
reducing laboratory-confirmed influenza transmission, either when worn
by infected persons (source control) or by persons in the general
community to reduce their susceptibility”
https://wwwnc.cdc.gov/eid/article/26/5/19-0994_article
Would love to have you share your take on this with the Chatlist.
END of Gene’s post
Lister had a very difficult task trying to encourage surgeons to wash their hands between surgical cases, so none of us should feel lonely in trying to encourage folks today to wash their hands or wear a mask. In fact, the primary problem that Ms. Xiao found in the papers she analyzed was lack of compliance in the study groups as compared to the controls; many people in the “control” groups wore masks anyway and washed their hands anyway. As was proper for her dissertation she included only Randomized Controlled Trials in her “meta analysis”(lumping a group of similar studies, hoping for improved insight, but usually just stirring already muddy water).
The quotes in Gene’s request for my opinion are true about our lack of the quality of evidence Ms. Xiao wanted. Note that she did no type of research that MIGHT provide evidence of higher quality. (I suspect that she hopes her paper will help her obtain a grant to do a real research project.) Such knowledge is greatly needed. We can only hope that such knowledge would have the desired effect on human behavior designed to reduce disease transmission. But when knowledge and belief conflict, belief will prevail. And all knowledge reaches the edge of observed cause and effect, at which point we all can only say, “I believe”.
Meanwhile, wash your hands, stay at home: when you must go out, as we all do from time to time, keep your social distance as well as possible, improve the effectiveness of social distancing by wearing your mask, carry a handy wipe for door knobs or rails or elevator buttons or vacuum tube capsules at the bank or gasoline pumps. Let’s smile with our eyes and say “Hello” and wave when we can. Friendly without being close.
I had business with Keith Hughes yesterday, and I felt very incomplete and uncertain not shaking hands! He did not have a mask on and redoing our contract to buy a TOL garage building took a half hour in his small office. I later felt wimpy for not asking him to mask while Nancy and I were there and won’t feel comfortable until at least 2 weeks without symptoms. We talked on the phone this morning, and I asked him to have a mask when Nancy returned to bring him the advance payment check. He had mask nearby but Nancy had to ask him to put it on, which he did. His office is air conditioned and was a relief from the fescue pollen yesterday – my excuse for not asking him to mask. Long story to illustrate the relativity of our behavior. So don’t be too quick to criticize until we “walk 7 miles in the other fellow’s moccasins”. But vote with our market power and patronize those merchants who care enough about us to wear a mask. Shun other customers who don’t wear a mask. Be friendly to those who do. Especially reward those businesses who require customers to mask; they run the risk of alienating non maskers.
John Dykers
bibliography of quotes from the same article,
“, efforts to control the next pandemic will rely largely on nonpharmaceutical interventions.”
“, influenza virus infections spread mainly in the community. Influenza virus is believed to be transmitted predominantly by respiratory droplets, but the size distribution of particles responsible for transmission remains unclear”
” Outside healthcare settings, hand hygiene is recommended in most national pandemic plans (/5/ <https://wwwnc.cdc.gov/eid/article/26/5/19-0994_article#r5>), and medical face masks were a common sight during the influenza pandemic in 2009. Hand hygiene has been proven to prevent many infectious diseases and might be considered a major component in influenza pandemic plans, whether or not it has proven effectiveness against influenza virus transmission, specifically because of its potential to reduce other infections”
” We did not generate an overall pooled effect of hand hygiene only or of hand hygiene with or without face mask because of high heterogeneity(the studies she was pooling had widely varying results) in individual estimates”
“A study conducted in the United States (/16/ <https://wwwnc.cdc.gov/eid/article/26/5/19-0994_article#r16>) showed no major effect of hand hygiene, whereas a study in Egypt (/18/ <https://wwwnc.cdc.gov/eid/article/26/5/19-0994_article#r18>) reported that hand hygiene reduced the risk for influenza by >50%”. (The study on hand washing in Egypt as done in a very impoverished school district. The control school had NO hand washing; the study school had especially installed running water and wash basins and soap. Influenza transmission was reduced by over 50%.)
“experimental studies have reported that influenza virus could survive on human hands for a short time and could transmit between hands and contaminated surfaces”
“Most studies(on face masks) were under powered (to do valid statistical analysis) because of limited sample size, and some studies also reported sub optimal adherence in the face mask group.”
“transmission should be reduced the most if both infected members and other contacts wear masks, but compliance in uninfected close contacts could be a problem (/12/ <https://wwwnc.cdc.gov/eid/article/26/5/19-0994_article#r12> ,/34/ <https://wwwnc.cdc.gov/eid/article/26/5/19-0994_article#r34>). Proper use of face masks is essential”
Ms. Xiao is a postgraduate student at the School of Public Health, University of Hong Kong, Hong Kong, China. Her primary research interests are influenza epidemiology and the dynamics of person-to-person transmission. She had 50 references to other papers in her bibliography. As the primary author, she was rather obviously doing a doctoral dissertation and included several colleagues as coauthors who were also cited in her bibliography.
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Doc –
Thanks so much for responding and taking a look at and analyzing the information for us.
I know that I and probably a lot of the Chatlist members greatly appreciate you doing this.
BTW, I have another curve ball starting high and inside and breaking down and away right into the strike zone down below.
Take a look at it. I’d appreciate your thoughts and those of others on the Chatlist.
Gene
Chatlist Admin
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Date: Fri, 15 May 2020 19:33:43 -0400
From: “John Dykers M.D.”
Subject: face masks and flu spread