-Anthony Fauci, Director of the National Institute of Allergy and Infectious Diseases
Handshake has become the first victim of COVID-19 epidemic. A harbinger of social distancing.
There are reasons to abolish a handshake. Ancient- since the 5th century B.C. as evidence that the hand holds no weapon. Sexists – women shake hands only in business. Patronizing and old-fashioned when business was done by a handshake of trust. And many other sins of human civilization. Japanese people are lucky because they do not have the handshake tradition. Unfortunately, the handshake cannot be replaced by nose greetings due to COVID-19. President Obama would not receive now a Maori hongi in New Zealand.
A start up lumber company is advertising online sterile disposable 6 feet sticks for stickshakes. Perhaps, this is just a rumor. Rumors are not rarity now. The Center Disease Control and Prevention (CDC) and Dr. Fauci are distributing contradictory statements which sometimes sound like rumors.
This eulogy precedes social distancing discussion. The notion of social distancing can compete only with wash your hands mantra as the main prophylactic tool in COVID-19 epidemic. While manufacturers of soap and other cleaning reagents are beneficiaries of the personal hygiene recent discovery, there are rumors that in the guise of common-sense epidemiology, social distancing can be used for political purposes and economy calamity. Of course, nobody would believe in such nefarious intentions.
Social distancing is the euphemism for physical distancing which sounds more precise though also ambiguous. Social distancing assumes people’s dispersion, kind of “molecularization”, although different steps of isolation and quarantine are necessary in the management of infectious disease and panic epidemics.
Quarantine is a medically determinate isolation. It is not the same thing as social distancing. It is a measure taken for people who may have been or might be exposed to the infection. Quarantine is imposed by government or public health organization. Social quarantine is not a commonly accepted term although it would reflect the situation when cities, districts, streets are closed or public events are cancelled or forbidden.
With the avalanche of coronavirus testing, a new popular term such as self-isolation is used. For example, when a football player is tested positive, he goes in self-isolation, quarantine “light”. Home arrest would sound too harsh. Self-seclusion would sound also unpleasant. People are social animals who left caves some years ago. Self-isolation is now also a good option for an official or politician to disappear for a while from the public eye. Zoom can provide a wink.
Anyway, social distancing is the most common term. It sounds artificially in a neighborhood. This is rather a communal dispersion. Social distancing sounds humoristic in a nuclear family relationship.
The social distancing notion is on the top of the COVID-19 epidemic containment triangle dogma (hand washing, mask wearing, and social distancing) which is proposed by every official or medical expert. The sequence of these recommendations depends at the speaker’s discretion.
Social distancing variants
The diagram presents main social distancing variants. Perhaps, a more comprehensive classification of social distancing variants exists. However, this diagram is only for orientation in epidemiological significance of different types of social distancing.
SARS-CoV-2 virus transmission
Of course, the goal of social distancing is the prevention of the virus transmission. It is assumed that COVID-19 disease transmission is determined in three ways: droplet of the infection virus (droplet nuclei), contacts, and aerosols. Each of them has different significance for social distancing. The triangle diagram approximately reflects this difference.
Droplet nuclei virus transmission is the most universally accepted reason for social distancing/physical distancing. It is commonly understood transmission from a person with symptoms or no symptomatic but able to shed viruses. Homo hominem lupus est. Man is wolf to man. Every person is a potential suspect of an epidemiologic danger. A healing premise for a society. The main reason to wear a mask additionally to social/physical distancing.
Transmission by contact with virus contaminated surfaces (fomites) is still discussed. Significance for social distancing is doubtful but it an argument for social self-isolation. However, fomites are the undisputable rationale for hand washing.
The most controversial and still disputable is aerosol virus transmission. Only by aerosol transmission could be explained many outbreaks in isolated groups without contacts with apparently ill persons. However, aerosol transmission still lacks scientifically credible studies. Aerosol transmission might be the reason for social distancing in common places, social quarantines, as well as for engineering specifications in construction or maintenance of common places.
This is the introductory post to detailed discussion of some aspects of social distancing. In the following posts will be discussed science behind 6 feet distance, aerosol transmission, and, yes, hand washing rationale. Unfortunately, there is no reliable science regarding social distancing background. Besides objective difficulties in obtaining experimental research data, social distancing dough is kneaded too tight with economic and politic that is not helpful in data collecting and especially in objective assessment of them.
6 feet (180 cm) individual distance is the commonly accepted implementation of individual social distancing. This post is going to present scientific stipulation data behind this notion. There will be repetitions of data mentioned in the previous posts, because each post addresses specific application of the commonly available data, but at a different angle.
6 feet (approximately 2 meters) origin
In 1934, William F. Walls, the Instructor for Sanitary Science at Harvard School of Public Health, published his studies of water droplets expelled from the human mouth in coughing, sneezing or loud talking. He calculated time taken by droplets of various size to fall two meters – the ‘ height of a tall man. He concluded that the falling velocity of a small droplet is proportional to the square of its diameter. The two meters distance which was determined by the instrument for bacterial examination in the air, developed at the Harvard School of Public Health in 1931, became the starting point of most studies, and eventually was transformed in 6 feet physical distance for social distancing.
Walls’ work is assumed as classic. There is the Wells Curve, which presents the effects of gravity and evaporation.
The Wells’ evaporation–falling curve of droplets helped in understanding the transmission by large and small droplets of infectious material. Wells’ study also presented the transformation of large droplets into ‘droplet nuclei’ by evaporation. Small droplets evaporate fast. The residual particulates are referred as aerosols(a suspension of particles in the air).
According to Wells (1955), the vehicle for airborne respiratory disease transmission is the droplet nuclei, which are the dried-out residual of droplets possibly containing infectious pathogens. Droplet nuclei is the main object of modern understanding of infectious material in viral diseases. Moreover, the Well’s inclination of using Newton’s gravitation notion led to the application of basic Stokes’s laws to connects velocity and movement of small spherical particles for better understanding of droplets.
In his articles, Walls warned that his experiments are intended to stimulate wider and more thorough studies of air-born infections. (Wells, W. F. (-11-01). “On Air-Borne Infection”. American Journal of Epidemiology. 1934; 20 (3): 611–618; Wells, W. F. On Air-borne Infection. Study II. Droplets and Droplet Nuclei. American Journal of Hygiene; 1934; Vol.20 pp.611-18).
Although later studies demonstrated that the droplet size at which evaporation outpaces falling is smaller than that described by Wells, and the settling time is longer, his work remains important for understanding the physics of respiratory droplets.
Current droplets studies
The concepts of large droplet transmission and airborne transmission have been extended and investigated over the last 70 years (Fennelly et al., 2004; O’Grady and Riley, 1963; Riley, 1974; Riley and O’Grady, 1961; Riley et al., 1962; Wells, 1955; Yassi and Bryce, 2004).
Two meters, or 6 feet, were conditionally chosen as the commonsense distance for experimental studies at the time when nobody expected that 6 feet notion would be the buzz word in the fight with COVID-19. Outbreaks of ‘Asian” epidemics in XXI century urged to revisit 2 meters previous studies at the more advanced experimental level. These studies naturally were done predominately in China. They were performed for the infectious disease transmission airborne routes developing engineering control projects.
The effects of droplet size, exhaled air velocity, and relative humidity on droplet evaporation and dispersion were examined following Walls methodology. When the relative humidity of the ambient air was taken into account in the indoor air environment , expelled free‐falling large droplets were carried away more than 6 m by sneezing, more than 2 m by coughing, and less than 1m through breathing. Horizontally expelled large droplets can also penetrate a longer distance. At a low relative humidity, more droplets and droplet nuclei could suspend in air, increasing the probability of aerolization. (How far droplets can move in indoor environments – revisiting the Wells evaporation–falling curve; 2007 Department of Mechanical Engineering; The University of Hong Kong).
The velocity parameters can be used to calculate the droplet spread distance and the safe distance to control the disease spread. Apparently, the breathing droplet velocity is lower than coughing and sneezing. In the review of more recent studies, the ranges of breathing droplet velocity are 0.1 to 1m/s, the transmission distance is about 1 m; the speaking droplet velocity is 2-10 m/s (average 3m/c). The patients’ coughed droplet concentrations change with the size into a peak rule. The velocity of the cough droplets is the biggest, the range of 10 to 25m/s, the transmission distance is more than 2m. (Documentary Research of Human Respiratory Droplet Characteristics Procedia Engineering; Volume 2015, Pages 1365-1374; Chongqing University, China).
However, there are also different data. For example, a direct quote from an article: “In order for droplet transmission to occur infected and susceptible persons have to be in close contact (several tens of cm apart), of comparable height and the sneeze or cough has to be directed in the “right” direction. The stopping distances of expelled particles provide another telling illustration of the complexities involved in droplet transmission: particles smaller than 488 μm (cough) or 232 μm (sneeze) will not travel further than 60 cm. (Quantifying the routes of transmission for pandemic influenza. Bulletin of Mathematical Biology. 2008; 70:820–867). Although these data are related to influenza viruses, the physical properties of a droplets are the same. In the latest World Health Organization recommendations for COVID-19, health care personnel and other staff are advised to maintain a 3-foot (1-m) distance away from a person showing symptoms of disease, such as coughing and sneezing.
A researcher in MIT from Fluid Dynamics of Disease Transmission Laboratory, however, found the distance should be 27 feet (810 cm) or even more due to turbulent gas cloud dynamics during sneezing by infected person (Bourouiba L, Dehandshoewoercker E, Bush JWM. Violent respiratory events: on coughing and sneezing. J Fluid Mech. 2014;745:537-563.Google ScholarCrossref; Bourouiba L. Images in clinical medicine: a sneeze. N Engl J Med. 2016;375(8):e15.PubMedGoogle ScholarLydia Bourouiba PhD,Turbulent Gas Clouds and Respiratory Pathogen Emissions. Potential Implications for Reducing Transmission of COVID-19. JAMA online, March, 26, 2020).
At a briefing by the White House’s coronavirus task force, a reporter asked Dr. Anthony Fauci, head of the National Institute of Allergy and Infectious Diseases (NIAID), about the potential for the coronavirus to travel 27 feet. Fauci went on to say he was “disturbed” by headlines about the virus traveling such distances “because that’s misleading. That means that, all of a sudden, the 6-foot thing doesn’t work.” The virus traveling distances that might be achieved after a vigorous sneeze is “not what we’re talking about” when it comes to social distancing, Fauci said, defending the 6-foot guideline.
Where are CDC’s and Dr. Fauci’s NIAID studies corroborated by other independent institutions about basics in SARS-CoV-2 spread, viability and other parameters crucial for everyday life and governmental policies?They had at least half a year to conduct these studies, never mind a decade since the Asian respiratory tract epidemic’s outbreaks. What are people doing in the huge building in Atlanta?
Presented material allows to come to some conclusions:
Center for Disease Control and Prevention (CDC) had not conducted any study for social distancing scientific support unless these data are under nondisclosure policy.
6 feet (2 meters) distance is elective commonsense measurement for social distancing which has not been supported by scientific data.
The wildfire of the COVID-19 pandemic is spreading through the world. The arsonists, all while hiding the matches, are offering their help to clean up the burned places by providing some essential protective necessities – all while being praised by the media which has always been in awe of autocratic regimes, starting with German and Italian fascists and their variants. The local Wuhan, China epidemic became a pandemic. The world has to handle this very much self-inflicted wound.
The tragic death count is on display, and the economic losses are well known, the current quarantine restrictions have changed the lives of people around/throughout the world. However, the unaccounted for result of COVID-19 is apparently a pandemic of fear. As a normal protective mechanism of living species, fear becomes damaging in excess for individuals, and is dangerous for politicians who are operating in the public eye of the masses.
These introductory words preclude my presentation of some issues pertaining predominately to safety in anatomic pathology laboratories under COVID-19 conditions. However, the observations and recommendations can be extrapolated to other individual and collective safety issues. They are written from the perspective of my experience as a Chief of Sanitary-Epidemiological Station back in Karelia, Russia, an experimental immunologist (PhD program), a clinical and anatomic pathologist (Leningrad-St. Petersburg), a pathologists’ assistant (including morgue attendant) and grossing technologist (Chicago).
As an epidemiologist, I was obliged to manage all ranges of actions during local epidemics including dysentery, hepatitis, and some sporadic cases of anthrax, tularemia, and others. While working in anatomic pathology, I tried to follow the safety rules, although I managed to accidentally stick my finger during an autopsy of a deceased acute HIV patient. The variability of conditions in individuals’ lives and work across different countries are incomparable. Every experience is limited and personal biases are inevitable, but the common denominator remains to be the rationality of actions under current circumstances.A different perspective might be useful for current COVID-19 and epidemics in the future.
This blog is focusing on “hot” topics. Three buzz words are dominating during current COVID-19 epidemic: hand washing, mask, social distancing with testing inside this triangle.
Hand washing, as a variant of disinfection, is self-explanatory action rooted in history of fighting epidemics. A mask is a natural instinct of locking the door before an intruder breaks in. Social distancing is a relatively new notion. Separation between potentially ill people at the voluntary chosen distance of 6 feet is relatively benign and acceptable by the frightened society. Are not self-destructive for humans prolonged social quarantines of healthy millions who want to work, go for shoping, come together for sport, entertainment, political, religious and other events?
The blog is going to address these issues in detail. They are not challenged in public and even science discourse. Surprisingly, the world entered the pandemic without reliable scientific data regarding these basic premises. We are entering our more than half a year of dealing with SARS-CoV-2 virus and we are still speculating over critical issues like virus transmission through aerolization.
Please, come back to the Blog’s COVID-19 categories. I’m often placing new and periodically updating some previous posts.
George Floyd’s death generated two COVID-19 epidemic questions. First is an epidemiologic question, the second is medical one.
Will be there an outbreak of mass hospitalizations and many deaths from COVID-19 in the nearest future after apparent violation of social distancing by thousands with or without mask wearing? It does not matter that most of them are young because they come home to their siblings, parents, and grandparents.
According to the autopsy report, George Floyd “was known to be positive for 2019-nCoV RNA on 4/3/2020” Why? Where? What were the actions after? However, two months later “Viral testing (Minnesota Department of Health, postmortem nasal swab collected 5/26/2020): positive for 2019-nCoV RNA by PCR.”
Is this a new infection? The autopsy has not revealed any morphological evidence of asphyxia caused by the police actions. Could not the COVID-19 infection precipitate the lethal outcome under conditions of significant occlusion of the coronary arteries (75 and even 90%%), as well as intoxication by drugs, according to the Toxicology Report?
Testing became the buzz word in solving the COVID-19 epidemic. The logic behind testing is apparent to everyone. Only the number of tests is discussed. Ashish Jha, director of the Harvard Global Health Institute thinks that 500,000 tests a day is need for the foreseeable future. The U.S. Nationwide COVID-19 testing capacity steadily increased to 145,000 tests a day. The White House unveils coronavirus testing plan to expand testing which are viewed as critical to reopening the economy.
The Michigan state COVID-19 provides Confirmed COVID-19 Cases, but it is unclear what the case means (https://www.michigan.gov/coronavirus/0,9753,7-406-98163_98173—,00.html). More than likely, the number of tested positively. This information or better disinformation only fuels scare- mongering without a real assessment of the epidemiological importance of testing. Remarkably, during the briefing in Kent county in Michigan on April 29th, the Health department refused to answer the direct question about the number of hospitalizations and death cases.
As now became the standard of the public discourse, the approaches to this specifically medical epidemiological issue are divided along the political party line with the underlining background of public fear, politician’s ignorance, and corporate business interests. The uncertainty is only how less than 365 million to test. The solution is vacillating between the test performance in the bank’s lobby or drive- through or ATM. The tendency is in implementing all three options with looming ahead options by mail or even the drone’s involvement.
On the serious note, testing issue requires professional approach cleared from todays fear and politically motivated aggregation with the focus on rational actions in the current epidemic and in the future outbreaks. There some methodology issues which should be solved.
The presented serial of posts will reflect my personal approach. Otherwise why bother to write. It is based on the infectious epidemiologist experience, familiarity with diagnostic immunology, and anatomic pathology practice. Some bias, which stems on experience collected in different time and competely different situations, is inevitable. However, the classic epidemiology rules still apply.
The diagram presents main variants of testing during COVID-19 epidemic.Molecular test is carried out by Reverse Transcription Polymerase Chain Reaction (rRT-PCR) for the qualitative detection of nucleic acid from SARS-CoV-2 in upper and lower respiratory specimens. Serum test are in determination of antibodies in plasma to SARS-CoV-2 virus.
U.S. Food and Drug Administration (FDA) has issued the first emergency use authorization (EUA) for a COVID-19 Antigen test in May. Antigen test is a “hybrid” test by the diagnostic purpose is closer to the molecular test, a sort of molecular test light. It will be discussed in a special post later.
The next posts will discuss the testing options separately. There are many details which are not discussed although they are crucial for the test’s implementation and the desired outcome.
COVID-19 testing, which gradually becomes sort of epidemiologic panacea, was discussed in the previous post, namely Epidemiological aspect of COVID-19 testing. The main conclusion from reviewed CDC documents regarding priority testing would be, in my opinion, misunderstanding of fighting major epidemic principles. CDC is following literally the infectious epidemiology orthodoxy. COVID-19 testing should have a detailed plan on the local (county) level.
While testing contacts of close to an ill person is a part of a standard infectious epidemiology procedure, COVID-19 screening is a new trend which requires detailed comprehensive evaluation. There should be a blend of detailed oriented actions with vision of the perspective in the end of epidemic, including in social and business life.
COVID-19 screening is a local epidemiology procedure. For example, in a local radio interview, Joann Hoganson, Kent county, Michigan Community Wellness Division Director brought up for screening different groups. She mentioned among other homeless, nursing homes residents though without door to door knocking.
This post presents some necessary components of a practical testing plan assuming that screening testing is necessary. Without these components the plan is not only insufficient but even contra productive. The three diagrams are the blueprint for any COVID-19 test screening local plan.
The actions after both positive and negative results of testing should be determined in detail for groups of people with certain follow up schedule.
While loosely determined critical infrastructure workers testing is questionable, health care personnel testing makes sense because their more possible encounters with the infection, better condition for obtaining the samples for reliable results and necessity of regular follow up.
The plan should specifically determine the type of the COVID-19 test. While Molecular RT-PCR test is quantitative, the Antigen nucleocapsid protein test is qualitative and more prone to false negative and even positive results. Antibody or convalescent serum test is not appropriate for screening unless it is used for serum therapy plasma collection and sentinel surveillance which is more the research realm.
The COVID-19 tests screening post is placed to draw attention to seriousness of these issue. The testing laboratories should be not only certified by Clinical Laboratory Improvement Amendments (CLIA), but an independent control of laboratories performance should be established. These issues will be discussed in the following posts. Unfortunately, the quality and reliability of the tests’ performance is taken as granted. My experience in conducting an epidemic taught me that laboratory might be sometimes a problem.
Tests screening requires a carefully developed detailed plan. Otherwise it is waste of time, resources, and source of confusion. I doubt that screening testing is necessary in the advanced stages of an epidemic. However, I do not have enough materials to confirm my opinion.
I wish I could see the detailed local (county) plan. However, it is not on the public display. Hopefully, it exists. I asked Kent county Health Department to see the plan, but nobody responded. I offered my experience, but no avail.
Although foreign experience cannot and should not be applied literally for many reasons, the Vietnam’s successes/experience is more in line with my understanding of epidemiological tactics. Without infatuations with testing, fast and aggressive quarantine at the local level is the way for fight an epidemic.
“We have a very strong system: 63 provincial CDCs (centers for disease control), more than 700 district-level CDCs, and more than 11,000 commune health centers. All of them attribute to contact tracing,” said doctor Pham with the National Institute of Hygiene and Epidemiology. https://www.msn.com/en-us/news/world/vietnam-how-this-country-of-95-million-kept-its-coronavirus-death-toll-at-zero/ar-BB14MxiR?ocid=spartandhp
This post is open ended. It reflects my vision of testing. I am going to get local materials on this subject, if they exist.
Reminiscences of my prior experience in epidemiologic practice might influence some bias to current approaches in COVID-19 epidemic.
My first job after medical school, as a doctor, was an epidemiologist position back in Russia, in Karelia near the Finland border in late 1960s. A rural place with scattered collective dairy and fur farms, lumber forest harvest factories surrounded by abounded GULAG camps. Periodic local epidemics were casual as fact of life. Dysentery, hepatitis A among people, sporadic anthrax, tularemia, foot-and -mouth disease among animals. Every epidemic had been managed from the start according infectious epidemiology rules: isolation, testing, hospitalization, local quarantine, disinfection, sanitary. In some occasions, the efforts to decrease the epidemic failed despite all standard efforts. One of the suspected culprits was the continuation of testing. When the testing was limited only to clinical necessity, the epidemic abruptly subsided. Until today, I do not have a rational explanation. Hypothetical thoughts are still lingering.
Some excerpts from basic epidemiology
Common sense and humans experience determine one of the main infectious epidemiology rules as the detection of infected to isolate from the population, as a rotten apple. Testing is an apparent solution. This post is intended to explore the testing notion as epidemiology tool to overcome the spread of COVID-19 epidemic in the USA.
Testing of patients, which require hospitalization or other clinical actions, is an apparent necessity for the differential diagnosis and effective treatment. The rest of testing is the epidemiology work routine. The diagram below presents main directions of this work. Testing with a clear plan of actions, which is following positive or negative result, only are part of them.
The importance of each component is different depending on infection, local conditions, morbidity, mortality etc. etc. In the case of COVID-19 epidemic, immediate contact testing prevails institutional contacts, while screening testing within a particular facility is incomparably more significant than the exposure testing to individuals. The latter issue requires special detailed discussion, a special post.
Below is the excerpt from PRIORITIES FOR COVID-19 TESTING section Evaluating and Testing Persons for Coronavirus Disease 2019 (COVID-19) by Center Disease Control and Prevention (CDC). Revisions were made on May 3, 2020
The entire document is pointing in the wrong direction from the epidemiology perspective. The serious objection would be on the division for High priority and Priority. The division itself and the content of the document reflect, in my view, misunderstanding by CDC strategic goals of actions in the current epidemic.
Practical epidemiology perspective
Below are my considerations regarding priorities in testing based on my prior experience as a practical infectious epidemiologist.
Hospitalized patients with symptoms are already isolated in the hospital. Their test should be done for the differential diagnosis followed by appropriate treatment.
Healthcare facility workers, workers in congregate living settings, and first responders with symptoms are already ill. Their testing is not a priority, but isolation them from contacts during their professional duties would be a priority with following testing just for clinical handling them as patients.
Residents in long-term care facilities or other congregate living settings, including prisons and shelters, with symptoms are really a high priority for separation them from the rest although this epidemiologic action would be right to do immediately even without a testing.
The testing of contacts is the necessity for localization of the source of infection. Although in a case of COVUD-19 epidemic this is a difficult task as usually in an airborne infection, an attempt would be justifiable.
“Persons without symptoms who are prioritized by health departments or clinicians, for any reason, including but not limited to: public health monitoring, sentinel surveillance, or screening of other asymptomatic individuals according to state and local plans.” These groups are a real priority for testing from the epidemiological approach, although they are in the end of the list of priorities. The main problem is that there are not local plans for such prioritizing, at least they are not in the public domain. For example, from Michigan Department of Health and Human Services
This document adds critical infrastructure workers category. The rationale is to diagnose in time infected and take them out for quarantine. When? How often? How? Etc. This document is in line with Michigan medical officials’ uninformative briefings.
Summary of epidemiological aspect of COVID-19 testing
First. Separation of the clinical and epidemiologic lines of testing should be clearly formulated in plans and actions.
Second. From the epidemiology perspective, the indication for testing of contacts includes two main groups: immediate contact with a clinically ill person and determination of individuals for testing in a contacts group. Aggressive and fast testing of infected and especially contacts in congregated living, public, and work settings is effective in the beginning of the epidemic. Screening is important in the case when the source of infection’s spread is unknown. However, screening brings mixed results when the epidemic is to some degree contained.
Third. 100 million tests per month as a maximal goal and 1 million tests per day is considered a realistic number. Unexperienced tracers, reluctant or over scared subjects of tracing, delayed or misdirected test results, and numerous other details brings only chaos. Testing become an exercise in futility. Lines of people seeking a test are also a way of potential virus shedders concentration. Most of them came for test due to the pandemic of scare, but some for a reason.
Fourth. The number of tests, as evidence of success in curtailing the epidemic, inevitably leads to relaxation of specimen’s collection, transportation, and the tests’ quality. The latter is accepted by the society as the Sun’s rise on the East. This issue will be discussed in a separate post.
The epidemiology theory orthodoxy should be adjusted to the current local conditions, economy and population attitude. My experience with epidemic on the ground suggest that the mass testing in wrong. It is a pretention of doing something with minimal positive results for an individual and maximal negative results for society: draining resources, expending the bureaucratic segment in the society, temptation of intrusion in private life under the pretense of common good, and increasing population’s anxiety. The epidemic will go by its own way determined by the rules of biology when society can correct it through diminishing the clinical damage to vulnerable people.
Everything in this epidemic is knead in sticky dough of politics. Only vaccine can compete with testing as a political issue, while the mask wearing is undisputable champion of the political divide.
Perhaps, the last. Testing infatuation already has taken a toll on the society’s mental health. Do we want to wince by our or somebody else sneeze? Do we want to measure the body temperature on permanent basis? Especially, we know how relative is this physiological parameter. Eventually the chronic fatigue syndrome will be the most frequent diagnosis.
I do not have an illusion that this post will change the course of actions during the current epidemic. Hopefully, my remarks regarding testing during an epidemic might be useful for infectious disasters in the future.
• and/or lower respiratory specimens: sputum (if produced) and/or endotracheal aspirate or bronchoalveolar lavage in patients with more severe respiratory disease.
Nasopharyngeal and oropharyngeal swabs are the commonly accepted standard. However, it is technically difficult procedure which require professional training. It is more easily present on the diagram than in a real situation (see both diagrams).
Anatomical conditions of nasopharyngeal specimen collection for COVID-19 molecular test. Red arrow- collection swab in, green arrow- swab out.
Collection a nasopharyngeal swab specimen is invasive. Following of the anatomical structure (conches), which is very much individual, require some training, skill and even instruments. Actually, this is a medical procedure. How far the swabs can reach in every collection? Are the swab’s handles calibrated for approximate depth of penetration? Many technical details can influence the test’s result.
The solution was found for the “testing, testing, testing” mantra.
“Remove preference for NP (nasopharyngeal) swabs” is among “Excerpts from CDC Summary of Recent Changes. Revisions were made on April 29, 2020 to reflect the following”.
In the list of acceptable specimens for initial diagnostic testing for SARS-CoV-2, CDC recommends:
“An anterior naris (nasal swab) specimen collected by a healthcare professional or by onsite or home self-collection (using a flocked or spun polyester swab)”.
The technical difficulty to obtain the specimen for molecular test from the most representative areas was substituted by simple nostril area. This substitution opens the gates to mass testing everywhere.
Drive-through screening centers have been designed and implemented in South Korea (Drive-Through Screening Center for COVID-19: A Safe and Efficient Screening System against Massive Community Outbreak. J Korean Med Sci. Published online Mar 16, 2020. https://doi.org/10.3346/jkms 2020 Mar 23;35(11). According to the article, this procedure increased testing capacity over 100 tests per day.
The real drive- through when a tested person opens the car’s window and a swab is poked in the nostril. You can see this procedure on the TV screen how.
The U.S. Food and Drug Administration (FDA) authorized option for the Laboratory Corporation of America (LabCorp) COVID-19 RT-PCR Test to permit testing of samples self-collected by patients at home using LabCorp’s Pixel by LabCorp COVID-19 Test home collection kit. A sample collected from the patient’s nose in saline is mailed to a LabCorp lab for testing. According to FDA Commissioner Stephen M. Hahn, M.D. the data demonstrated from at-home patient sample collection is as safe and accurate as sample collection at a doctor’s office, hospital or other testing site. 30 participants (?!) were enrolled in a self-collection study by LabCorp.
This post will explore only nares specimen collection for COVID-19 RT-PCR test from the nostril’s anatomy, histology, and pathophysiology aspect leaving aside clinical, epidemiological, and medical statistic aspects and other details of this type of specimen collection. These issues require a special post.
Nostrils as part of the nasal cavity are initially a continuation of the skin lined with squamous epithelium and different size of hair. Their protective role is in preventing dust entering the respiratory tract, but it serves also of stopping infections materials, especially droplet containing airborne microorganisms. In this regard, droplet nuclei containing SARS-CoV-2 virus are “hanging” on the hair even without touching the surface of the nostril. Squamous epithelium lining of the anterior nares is followed by ciliated epithelium whose cilia form a carpet on which dust settles, as well as droplet nuclei might be engulfed by mucus. The virus, if it is there became the target of first line of immunology defense through intensive mucus production and tool of cellular (macrophages , T-lymphocyte cells). All these popular biology data are presented here just to show the place where the collection swabs is operating.
By the way, this operation is not completely innocent. During this collection manipulations, the droplet nuclei might be taken off the defense line provided by nostrils hair and pushed further into nose cavity which would not be right.
Every specimen collection has some uncertainty. Deviation of the standard bring additional confusing data. Is the method of collection reflected in the at the requisition form documents? As an extraordinary exception with the mark.
Positive SARS-CoV-2 virus molecular test is only evidence of virus presence in the nose’s content when the virus hasn’t even interacted with a person ‘s first line of innate immunity defense response.
The nares collection area for the SARS-CoV-2 virus molecular test can be done only as an extraordinary exception with the special mark. The clinical and epidemiological interpretation of the result should take into account the nares collection area.
Wearing a mask by general public in private and social life during the COVID-19 epidemic has different approaches. This post presents my personal opinion which has been gradually formed by emerging facts and deeper understanding of the current epidemiological situation. However, unfortunately, we have minimal scientifically supported data and maximal fear-mongering statements. The main goal of this post is in presenting rationality of mask wearing in private life.
Addition on 6/21/20. Unfortunately, wearing a mask has become a political statement. Only few were wearing a mask during Trump’s rally in Tulsa, Oklahoma om 6/20/20. In Belorussia, the President Lukashenko opponents are wearing a mask as a demonstration of the rejection of his corona virus skepticisms.
This post violates the rules of the short size of a Blog’s entry. The subject requires a comprehensive presentation because the mask wearing issue became a civil life event.
The readers, who are in haste to conclusions, can omit some pages. Many details reflect some of my literature research work which support my opinion. The most available sources are related to influenzas and prior coronavirus epidemics. World Health Organization (WHO) separated COVID-19 from other coronaviruses outbreaks. Without going in the politically charged viruses classification terminology, SARS-CoV-2 virus is the closest relative of SARS-CoV, first cousin. For the wearing a mask issue, these viruses discharge pattern is the same.
Only in rare occasions, some references are provided, because this post is not a scientific study. It is rather an opinion on the background of pathophysiology, environment physics, my experience as a laboratory practitioner, and… some common sense.
Elective masks’ classification
Surgical operational mask
The surgical mask serves to protect the operation field and the operative room from infectious contamination. The use of this kind of masks is undisputable. Now even dental hygienists use them though also for self-protection.
Mask for an ill person
Wearing a mask by an ill person with symptoms of potentially infectious discharge (or even without) is in the same line, although more nuanced, as a surgical mask. Even positively tested, as socially considerate citizens, might be required to wear one, if they would not be in a quarantine confinement. This issue along with rationality of testing itself requires special discussion.
Professional PPE mask
Masks, as part of Personal Protective Equipment (PPE) predominately in anatomic pathology laboratory, were discussed in previous posts. OSHA regulation are the bottom line with some variant depending on the local implementation. The principles can be extrapolated to other areas in medical field with some correction of the assigned procedures, especially during the care for COVID-19 patients in the acute stage of the disease.
Mask as part of civilian life, a “street mask”
The current post is going to touch on the topic of wearing a mask which can loosely be called a private life mask, or elected mask, or civilian mask, or casual mask, or a “street mask” or any better name during the COVID-19 epidemic.
Since April 12th, wearing a mask outdoors is mandatory in Israel. Although there some exceptions for certain categories of situations, such a ruling for the entire country requires a close look. Is not unjustified fear or other, including political considerations, influence such decision? Is there a reliable research support?
There is a no-love triangle in the epidemic outbreak where the mask, the object of this post, has been caught in the middle. The Diagram presents the participants which cannot be separate in real live, but need to be discussed separately for the sake of a comprehensive approach. The virus, the culprit, being on the top of the triangle in the ambient environment is infecting individuals. Their encounter creates an epidemiological “crime scene”.
Virus: the intruder, the culprit
Supposedly, we have reliable information about SARS-CoV-2 virus (or COVID-19 virus), when human-to-human transmission of the SARS-CoV-2 in Wuhan, China, began in December 2019. The name SARS-CoV-2 virus was selected by International Committee on Taxonomy of Viruses due to the nucleotide sequence similar to SARS-CoV which caused the 2003 SARS epidemic.
SARS-CoV-2 virus is an enveloped particle containing single-stranded RNA associated with a nucleoprotein within a shell of matrix protein. The envelope bears projections which glycoproteins are responsible for attachment to the host cell. After the virus enters the host cell and uncoats, the genome is transcribed and then translated. The mRNAs form a unique “nested set” by budding from host cell membranes. This is a short description of the virus’s initial nefarious behavior in the infected area.
Person: the host, the victim
An incoming coronavirus needs to find epithelial cells to invade the host. It intrudes predominately into the respiratory tract. The intrinsic barrier on the mucosal surface of the respiratory epithelium provides the first line of defense against respiratory viruses. Mucus layers can effectively trap the virus before it can enter the host cells. Infected cells become vacuolated. Cell damage triggers the production of inflammatory mediators, which in turn increases nasal secretion and causes local inflammation and swelling. Mucociliary Clearance Apparatus (MCC) serves as a key mechanism for eliminating the intruders from the respiratory epithelial surface. If that protection fails, they move toward the larynx, where mucus containing the entrapped virus is swallowed or expectorated (Seasonality of Respiratory Viral Infections. Annual Review of Virology; 2020, 7:2.1–2.19).
This local reaction to the virus intrusion is relevant to the mask wearing topic. These responses stimulate sneezing and obstruct the airway, and raise the temperature of the mucosa or even the body’s temperature. Relationship between temperature, humidity, and COVID-19 virus can increase host’s susceptibility to infections. Inhalation of cold dry air directly affects the upper airway mucosa, impairs mucociliary clearance, and increases mucin production, as well as potentially causing epithelial damage.
The subject of this post is the protective mask. It is important to visualize what happens when the virus is leaving the infected nasopharyngeal and orotracheal areas, through sneezing, coughing, even speaking, and perhaps just in minimal skin contact in form of snot, sputum, saliva, and skin cornea. The virus is not “naked” (it is impossible), but now it is coated by mucus and large and small droplets of water that depends very much on air humidity. Components of the mucus are 93– 97% w/w water.
Direct contact transmission occurs either indirectly through contact with infected (by virus) secretions or directly through physical touch between an infected individual and a susceptible person. Just common sense, it cannot be managed by mask or its absence.
Droplet spray in shortrange transmission can be prevented by a mask. This is a purpose of the mask as part of PPE. Droplet transmission requires the source of infectious to directly spray large droplets by coughing or sneezing onto mucous surfaces or eye conjunctiva of a susceptible person.
The overwhelming majority of person-to-person transmission happens indoors through discharge by an ill person through droplet spray in shortrange transmission. Wearing a mask by an ill person, besides apparent rationale of preventing the discharge of the virus, requires a closer look at scientific data which support this notion. The load of infections material, frequency of encounters, proximity from the individual with discharge, and other epidemiological details require scientifically reliable data.
A direct quote from an article: “In order for droplet transmission to occur infected and susceptible persons have to be in close contact (several tens of cm apart), of comparable height and the sneeze or cough has to be directed in the “right” direction. The stopping distances of expelled particles provide another telling illustration of the complexities involved in droplet transmission: particles smaller than 488 μm (cough) or 232 μm (sneeze) will not travel further than 60 cm. (Quantifying the routes of transmission for pandemic influenza. Bulletin of Mathematical Biology. 2008; 70:820–867). Although these data are related to influenza viruses, the physical properties of a droplets are the same. They punch a hole in the established in 1930th 6 feet (2 meters) distance notion (Wells WF. On air-borne infection. Study II. Droplets and droplet nuclei. American Journal of Hygiene. 1934; 20:611–618). A researcher in MIT from Fluid Dynamics of Disease Transmission Laboratory, however, found the distance should be 27 feet (810 cm) or even more due to turbulent gas cloud dynamics during sneezing by infected person (Turbulent Gas Clouds and Respiratory Pathogen Emissions. Potential Implications for Reducing Transmission of COVI-19. JAMA online, March, 26, 2020).
In a close expiratory event, a close cough is unlikely (≈1% probability) to generate traditional droplet transmission (i.e., direct deposition on the mucous membranes), although a close, unprotected and horizontally-directed sneeze is potent enough to cause droplet transmission (Quantifying the routes of transmission for pandemic influenza. Bulletin of Mathematical Biology. 2008; 70:820–867).
Virus inactivation should be taken into account, as well as gravitational settling of particles with supposedly viruses. This understanding can contribute to rational use of the mask under certain working conditions and in private life.
Aerosol transmission is far more dominant than contact transmission for influenza. Aerosol in long-range transmission should be divided into indoors and outdoors transmission. The latter is in the background of the personal mask (“street mask” indoors and outdoors) employment. Airborne transmission through droplet nuclei does not require face-to-face contact with a person who is prone to be infected.
SARS-CoV-2 virus in COVID-19 is completely similar to influenza viruses by the physical features of distribution in droplets transmission. The differences might start at the level when the virus is uncoated from its envelop and start relationship with the invaded host.
Outdoors, transmission occurs at close ranges rather than over long distances. The airborne transmission in this situation is unlikely to be of significance in most clinical settings. (Transmission of influenza A in human beings. Lancet Infect. Dis. 2007. 7:257–65). Outdoor aerosol transmission is not likely due to dilution and dispersion by ambient wind speeds and turbulence, whereas in closed environments, particularly with low ventilation, aerosol transmission is more likely. (High infectivity and pathogenicity of influenza A virus via aerosol and droplet transmission. Epidemics. Volume 2, Issue 4, December 2010, Pages 215-222).
The low humidity and lower temperature environment would promote the viability of SARS-CoV-2 in the droplets and impaired ciliary clearance and innate immune defense, for robust access to the deep lung tissue and rapid transmission between infected individuals.
Stability of Respiratory Viruses
The stability of SARS-CoV-2 was similar to that of SARS-CoV-1 under the experimental circumstances tested. This indicates that differences in the epidemiologic characteristics of these viruses probably arise from other factors, including high viral loads in the upper respiratory tract and the potential for persons infected with SARS-CoV-2 to shed and transmit the virus while asymptomatic. There are some statements that the virus can remain viable and infectious in aerosols for hours and on surfaces up to days (depending on the inoculum shed). These findings echo those with SARS-CoV-1, in which these forms of transmission were associated with nosocomial spread and super-spreading events, and they provide information for pandemic mitigation efforts. (Aerosol Surface Stability New England Journal Medicine nejm.org on April 12, 2020).
Some sources state that the virus can hang around in the air for at least 3 hours, but this statement does not have a reliable experimental support. A special study reports the virus viability 5.6 hours on stainless steel and 6.8 hours on plastic surface. These sporadic data are only partially related to the topic of this post, namely casual mask wearing. They are the decontamination and disinfection issues, which require a separate discussion.
The presented above available to me research data are in the background of my understanding of wearing a protective mask just in private life outside a medical facility, diagnostic or clinical. I am open to changes in my view if new data would look reliable to me.
A special masks comparison discussion will be posted later. Now, I want to discuss the rationality of manufactured or various self-made “masks”, simple improvised scarfs.
Should the use of face masks be recommended during a pandemic on the basis of current knowledge of airborne or droplet transmission?
It looks like airborne transmission is important only indoors. Outdoors, where virus discharge is by dilution, air circulation and higher virus inactivation, the transmission is, in my view, questionable. However, even indoors use of a face mask requires some sober considerations.
If we exclude very exceptionally rare situation when a COVID-19 ill person coughs or sneezes in close proximity (2 feet), the casual face mask is used to protect from viruses that presumably exist in the room. They are distributed diffusely in the area of a person presence. It means, that the same particles of droplets, containing viruses, are at the surface of the mask and other areas of the face (forehead, eyes, remaining part of the cheeks, etc.), as well as hear, hands and cloth equally.
Viruses invade predominately the respiratory tract via the nose or open mouth and less through eye conjunctive. The droplets containing viruses don’t know where the nose is, they don’t have a GPS. The wet and warm mask provides the virus in droplets (droplet nuclei) a comfortable dwelling surface. The mask becomes a hotbed for viruses. When the mask is taken off, the droplets inevitably are disseminated in close proximity to the “infection gates” (nose, mouth, eye conjunctive). The person’s wet and warm breath through the mask also provides the surrounding face’s skin with some additional humidity for viable viruses which would otherwise dry out on the skin’s surface. Semidried droplets become lighter for take off from the skin. By air circulation, hands manipulations and other ways, they can find their way to the nose or mouth because the power of active inhale prevails over power of the passive exhale.
Practical advice: when the face mask is taken off, wash with soap not only your hands but also your face and the exposed parts of the neck.
Breathing through the mask is not the best evolutionary achievement for the humans. The nose is the first line of defense. The nasopharyngeal and oropharyngeal areas are the second lines of immunological defense. Would it not be reasonable to let them do their defense work under natural physiological conditions if some amount of viruses sneaked behind the infection gates? We cannot seal them off from entry of a pathological agent completely.
Very rarely, the masks are taken off according to the infection disease professional rules – slowly rolling with the mask’s outside in. Actually, facial masks designed in the respirators dome form cannot be taken off in this manner. Such way of taking the mask off is also just impossible for an improvised mask made from a kerchief. There are other details of handling the face masks outside the medical facility that makes it, in my view, useless for an individual’s employment and undesirable from epidemiological point.
Community life aspect
We see that almost all people in China are wearing masks. Besides, they are used to wearing them due to living in highly polluted cities, so this is more of a psychological phenomena.
Of course, some exceptions should be made for immunocompromised individuals, but they should be instructed to follow safe use of the mask which should protect them not only from SARS-CoV-2.
Some additional questions
Is a grocery store, supermarket or smaller size store an indoor space during COVID-19?
Do we want a socially devastating life when people move around with Pitbull’s muzzles? How long will this last, and who will decide when it is time to take the masks off? Would it be for now right to go on a date equipped also with gloves, perhaps double gloves just in case, and a respirator? Maybe, a mask will be a part of our attire for a foreseeable future, keeping in mind second waves of many epidemics?
While working on the cytotoxins antibodies history in experimental immunology, I was impressed by how deep immunologists had dived into the cell structure. By contrast, during the current post’s preparation, I was surprised how shallow infectious epidemiology swims in determination of the airborne infections dissemination.
Would it not be right, for the institutions in charge of current epidemic to arrange simultaneous multiple corroborative and clandestine from each other studies on the infamous 6 feet social distancing? Is not a shame that this distance is based on 90 and 70 years ago studies (WF Wells)? Those would not be a long and expensive studies.
Is not it time to separate the real knowledge from urban legends in such a serious act of placing the whole country on a complete standstill?
Is the probability theory still a tool for mathematical models based on reliable data?
Meanwhile, let people have some fun in masks creation, like below. Bandanas (Bandannas) now became a fixture of fashion.
House Speaker Nancy Pelosi is wearing masks suited to her outfit. A pink mask to a pink dress. a stripped to a dress with stripes. There are masks with political statements or just for fan pictures.
However, to make the mask as a part of attire in public areas is , in my view, an unsubstantiated overkill. The society would pay a substantial price for such self-destruction.