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There is a rather dishonest Igraham segment circulating online about masks. So I thought I would take a look at it. This type of misinformation is actively harmful. Here is how she cherry-picked and misrepresented data. 1/ https://twitter.com/Erick_in_Cali/status/1283618248433430528
We start with "why is everyone else opening schools without a problem?" Well, because they (Asia and Europe) have much lower levels of disease transmission. She cites an "extensive new German study that shows kids can't readily spread the virus." 2/
False. The "study" was a simple antibody prevalence survey of antibodies in students and teachers. It found that only 12 of 2000 tested had antibodies. It was done in Saxony, Germany which has a very low rate of infection relative to other states. 3/ https://www.theguardian.com/world/2020/jul/13/german-study-covid-19-infection-rate-schools-saxony
At no point can we make a claim from serology testing about the infectivity of a specific population. It is simply a snapshot in time. The results were in line with sampling of the general German population, simply confirming that disease prevalence in Germany is LOW. 4/
Everyone wants children back in school. There is a big difference between sending children back to school as Germany did (with very low levels of disease) and sending them back to school in a place like Florida or California. 5/
She then says that we only have a problem in 4 states. Takes it a step further by blaming the increasing cases on travel from south of the border. Also False. We have consistently had higher per capita rates than Mexico. (Although testing levels are also lower in Mexico) 6/
Then, a glimmer of truth. Arizona does in fact appear to be plateauing. This is good news and hopefully the trend will continue. 7/
Now onto mask mandates. What does the "science" tell us? Here, Laura takes a study from 2015 about mask use *IN THE HEALTH CARE SETTING* and uses it to say that masks are harmful in the *PUBLIC* setting. 8/ https://bmjopen.bmj.com/content/5/4/e006577
She then selectively edits the conclusion to "the results caution against cloth masks. This is an important finding to inform occupational health and safety." She completely ignores the context of health care workers. 9/
Actual conclusion from that study: "as a precautionary measure, cloth masks should not be recommended for Health Care Workers, particularly in high-risk situations, and guidelines need to be updated." To be clear, no one is advocating for HCWs to wear cloth masks. 10/
She then jumps to WHO guidance, but pay attention, because now she is reversing course and using language critical of *Medical* masks in *public*. This is a 16 page document with many parts. To be clear, no one is recommending medical masks for the general public. 11/
Full WHO document. 12/ https://www.who.int/publications/i/item/advice-on-the-use-of-masks-in-the-community-during-home-care-and-in-healthcare-settings-in-the-context-of-the-novel-coronavirus-(2019-ncov)-outbreak
There is lots of conflicting evidence on the use of masks. Science is difficult. Despite this, masks remain a useful tool in preventing transmission in situations where distancing is not possible. WHO still recommends masks to decrease transmission in these scenarios. 13/
Then we get back to the CDC recommendations against public mask use in January. This has been explained many times. PPE supplies were so short at that time, that any public use of medical masks (not necessary, see above) was taking away supply from HCWs (necessary). 14/
Now, the Nature study. First of all, this study looks at influenza, rhinovirus, and seasonal coronavirus, not sars-cov-2; so direct applicability *could* be limited. Furthermore, she plays loose with aerosols vs droplets. 15/ https://www.nature.com/articles/s41591-020-0843-2
It is not at odds with current data to report that many infected individuals do not shed virus (a good thing). However, the super-spreader phenomenon is well established and its impossible to know who is such a carrier (hence, masks for all) 16/ https://www.scientificamerican.com/article/how-superspreading-events-drive-most-covid-19-spread1/
The study was also limited by low numbers, making significant findings more difficult to achieve. Even given the limitations, the authors still claim the results support that masks can reduce the transmission of respiratory droplets. 17/
She also misrepresents the degree of symptoms that study participants had (less than half had a fever). She then finishes by chastising "experts." 18/
Moral of the story: Please don't get your health information from Opinion hosts who flash cropped excerpts from studies on the screen. Wear a mask in public and in situations where you can't appropriately distance.
That was exhausting. @ddale8, I don't know how you do it. fin/
That was exhausting. @ddale8, I don't know how you do it. fin/
