{"id":233826,"date":"2021-05-13T06:55:00","date_gmt":"2021-05-13T06:55:00","guid":{"rendered":"http:\/\/www.thetruthseeker.co.uk\/?p=233826"},"modified":"2021-05-14T06:40:40","modified_gmt":"2021-05-14T06:40:40","slug":"a-misleading-c-d-c-number","status":"publish","type":"post","link":"https:\/\/www.thetruthseeker.co.uk\/?p=233826","title":{"rendered":"A Misleading C.D.C. Number"},"content":{"rendered":"

David Leonhardt \u2013 New York Times May 11, 2021<\/strong><\/h1>\n

When the Centers for Disease Control and Prevention<\/a> released new guidelines last month for mask wearing, it announced<\/a> that \u201cless than 10 percent\u201d of Covid-19 transmission was occurring outdoors. Media<\/a> organizations<\/a> repeated<\/a> the statistic<\/a>, and it quickly became a standard description of the frequency of outdoor transmission.<\/p>\n

But the number is almost certainly misleading.<\/p>\n

It appears to be based partly on a misclassification of some Covid transmission that actually took place in enclosed spaces (as I explain below). An even bigger issue is the extreme caution of C.D.C. officials, who picked a benchmark \u2014 10 percent \u2014 so high that nobody could reasonably dispute it.<\/p>\n

That benchmark \u201cseems to be a huge exaggeration,\u201d as Dr. Muge Cevik, a virologist at the University of St. Andrews, said. In truth, the share of transmission that has occurred outdoors seems to be below 1 percent and may be below 0.1 percent<\/a>, multiple epidemiologists told me. The rare outdoor transmission that has happened almost all seems to have involved crowded places or close conversation.<\/p>\n

Saying that less than 10 percent of Covid transmission occurs outdoors is akin to saying that sharks<\/a> attack fewer than 20,000 swimmers a year. (The actual worldwide number is around 150.) It\u2019s both true and deceiving.<\/p>\n

This isn\u2019t just a gotcha math issue. It is an example of how the C.D.C. is struggling<\/a> to communicate effectively, and leaving many people confused about what\u2019s truly risky. C.D.C. officials have placed such a high priority on caution that many Americans are bewildered by the agency\u2019s long list of recommendations. Zeynep Tufekci of the University of North Carolina, writing in The Atlantic<\/a>, called those recommendations \u201csimultaneously too timid and too complicated.\u201d<\/p>\n

They continue to treat outdoor transmission as a major risk. The C.D.C. says<\/a> that unvaccinated people should wear masks in most outdoor settings and vaccinated people should wear them at \u201clarge public venues\u201d; summer camps<\/a> should require children to wear masks virtually \u201cat all times.\u201d<\/p>\n

These recommendations would be more grounded in science if anywhere close to 10 percent of Covid transmission were occurring outdoors. But it is not. There is not a single documented Covid infection anywhere in the world from casual outdoor interactions<\/a>, such as walking past someone on a street or eating at a nearby table.<\/p>\n

Today\u2019s newsletter will be a bit longer than usual, so I can explain how the C.D.C. ended up promoting a misleading number.<\/p>\n

The Singapore mystery<\/h2>\n

If you read the academic research that the C.D.C. has cited in defense of the 10 percent benchmark, you will notice something strange. A very large share of supposed cases of outdoor transmission have occurred in a single setting: construction sites in Singapore.<\/p>\n

In one study<\/a>, 95 of 10,926 worldwide instances of transmission are classified as outdoors; all<\/em> 95 are from Singapore construction sites. In another study<\/a>, four of 103 instances are classified as outdoors; again, all four are from Singapore construction sites.<\/p>\n

This obviously doesn\u2019t make much sense. It instead appears to be a misunderstanding that resembles the childhood game of telephone, in which a message gets garbled as it passes from one person to the next.<\/p>\n

The Singapore data originally comes from a government database there. That database does not categorize the construction-site cases as outdoor transmission, Yap Wei Qiang, a spokesman for the Ministry of Health, told my colleague Shashank Bengali<\/a>. \u201cWe didn\u2019t classify it according to outdoors or indoors,\u201d Yap said. \u201cIt could have been workplace transmission where it happens outdoors at the site, or it could also have happened indoors within the construction site.\u201d<\/p>\n

As Shashank did further reporting, he discovered reasons to think that many of the infections may have occurred indoors. At some of the individual construction sites where Covid spread \u2014 like a complex for the financial firm UBS<\/a> and a skyscraper project called Project Glory \u2014 the concrete shells for the buildings were largely completed before the pandemic began. (This video<\/a> of Project Glory was shot more than four months before Singapore\u2019s first reported Covid case.)<\/p>\n

Because Singapore is hot year-round, the workers would have sought out the shade of enclosed spaces to hold meetings and eat lunch together, Alex Au of Transient Workers Count Too, an advocacy group, told Shashank. Electricians and plumbers would have worked in particularly close contact.<\/p>\n

Are schools outdoors?<\/h2>\n

How, then, did the Singapore cases get classified as they did?<\/p>\n

When academic researchers began collecting Covid data from around the world, many chose to define outdoors spaces very broadly. They deemed almost any setting that was a mix of outdoors and indoors to be outdoors.<\/p>\n

\u201cWe had to settle on one classification for building sites,\u201d Quentin Leclerc, a French researcher and co-author of one of the papers<\/a> analyzing Singapore, told me, \u201cand ultimately decided on a conservative outdoor definition.\u201d Another paper<\/a>, published in the Journal of Infection and Public Health, counted only two settings as indoors: \u201cmass accommodation and residential facilities.\u201d It defined all of these settings as outdoors: \u201cworkplace, health care, education, social events, travel, catering, leisure and shopping.\u201d<\/p>\n

I understand why the researchers preferred a broad definition. They wanted to avoid missing instances of outdoor transmission and mistakenly suggesting that the outdoors was safer than it really was. But the approach had a big downside. It meant that the researchers counted many instances of indoors transmission as outdoors.<\/p>\n

And yet even with this approach, they found a minuscule share of total transmission to have occurred outdoors. In the paper with 95 supposedly outdoor cases from Singapore, those cases nonetheless made up less than 1 percent of the total. A study from Ireland, which seems to have been more precise about the definition of outdoors, put the share of such transmission at 0.1 percent<\/a>. A study of 7,324 cases from China found a single instance<\/a> of outdoor transmission, involving a conversation between two people.<\/p>\n

\u201cI\u2019m sure it\u2019s possible for transmission to occur outdoors in the right circumstances,\u201d Dr. Aaron Richterman of the University of Pennsylvania told me, \u201cbut if we had to put a number on it, I would say much less than 1 percent.\u201d<\/p>\n

Britain\u2019s scientific approach<\/h2>\n

I asked the C.D.C. how it could justify the 10 percent benchmark, and an official there sent this statement:<\/p>\n

There are limited data on outdoor transmission. The data we do have supports the hypothesis that the risk of outdoor transmission is low. 10 percent is a conservative estimate from a recent systematic review of peer-reviewed papers. CDC cannot provide the specific risk level for every activity in every community and errs on the side of protection when it comes to recommending steps to protect health. It is important for people and communities to consider their own situations and risks and to take appropriate steps to protect their health.<\/p>\n

Erring on the side of protection \u2014 by exaggerating the risks of outdoor transmission \u2014 may seem to have few downsides. But it has contributed to widespread public confusion about what really matters. Some Americans are ignoring the C.D.C.\u2019s elaborate guidelines and ditching their masks<\/a>, even indoors, while others continue to harass people<\/a> who walk around outdoors without a mask.<\/p>\n

All the while, the scientific evidence points to a conclusion that is much simpler than the C.D.C.\u2019s message: Masks make a huge difference indoors and rarely matter outdoors.<\/p>\n

The health authorities in Britain, notably, seem to have figured this out. They have been more aggressive about restricting indoor behavior, locking down many businesses again late last year and requiring masks indoors even as most of the country is vaccinated. Outdoors, however, masks remain rare<\/a>.<\/p>\n

It certainly doesn\u2019t seem to be causing problems. Since January, daily Covid deaths in Britain have declined more than 99 percent<\/a><\/p>\n

Source\u2026<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

The C.D.C. says that unvaccinated people should wear masks outdoors. However, this appears to be a huge exaggeration of threat posed by Covid-19. For there is NOT A SINGLE documented case of Covid-19 being transmitted in the open air <\/p>\n","protected":false},"author":39262,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":"","footnotes":""},"categories":[105],"tags":[],"class_list":["post-233826","post","type-post","status-publish","format-standard","hentry","category-coronavirus"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.thetruthseeker.co.uk\/index.php?rest_route=\/wp\/v2\/posts\/233826","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.thetruthseeker.co.uk\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.thetruthseeker.co.uk\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.thetruthseeker.co.uk\/index.php?rest_route=\/wp\/v2\/users\/39262"}],"replies":[{"embeddable":true,"href":"https:\/\/www.thetruthseeker.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=233826"}],"version-history":[{"count":8,"href":"https:\/\/www.thetruthseeker.co.uk\/index.php?rest_route=\/wp\/v2\/posts\/233826\/revisions"}],"predecessor-version":[{"id":233941,"href":"https:\/\/www.thetruthseeker.co.uk\/index.php?rest_route=\/wp\/v2\/posts\/233826\/revisions\/233941"}],"wp:attachment":[{"href":"https:\/\/www.thetruthseeker.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=233826"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.thetruthseeker.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=233826"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.thetruthseeker.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=233826"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}