Social Distancing Introductory Overview

Social distancing terminology

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 Individual Distance Rationale

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.

Wells’ Curve
Wells’ Curve dependence droplet diameter, evaporation, and falling time



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.

Introduction to COVID-19 pandemic

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.

Floyd’s death COVID-19 questions

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?

Introduction to COVID-19 Tests

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.

Main variants of testing during COVID-19 epidemic.

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 tests screening

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 blueprint of testing plans

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.

Types of test in laboratory practice

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.

Organizational issues of COVID-19 testing

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.  

Epidemiological aspect of COVID-19 testing

Some reminiscences

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.

Testing priorities

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.

Specimen collection for molecular tests

Significance of the specimen collection area for the virus molecular test (nucleic acid amplification tests (NAAT), such as RT-PCR) is apparent.

According to the World Health Organization (WHO):

At minimum, respiratory material should be collected:

upper respiratory specimens: nasopharyngeal and oropharyngeal swab or wash in ambulatory patients;

• 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).

Diagram of the nasopharyngeal test specimen collection

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”.

And now:

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.

Conclusion

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.

ICD-10 code for COVID-19

The correct medical statistics is crucial during an epidemic. The mortality data are particularly significant during COVID-19 because it is one of the unusual signs of this epidemic.           

National Vital Statistic System (NVSS) issues COVID-19 Alert No. 2 letter on March 24, 2020 that “a newly-introduced ICD code has been implemented to accurately capture mortality data for Coronavirus Disease 2019 (COVID-19) on death certificates.” “The new ICD code for Coronavirus Disease 2019 (COVID-19) is U07.1.”

The letter includes also a puzzling paragraph: “The WHO [World Health Organization] has provided a second code, U07.2, for clinical or epidemiological diagnosis of COVID-19 where a laboratory confirmation is inconclusive or not available. Because laboratory test results are not typically reported on death certificates in the U.S., NCHS [National Center for Health Statistics] is not planning to implement U07.2 for mortality statistics”. (Bold and [ ] brackets added).

Epidemiological diagnosis exists only in WHO’s heads. There are clinical and post mortem/autopsy diagnoses. The latter is not mentioned at all. Clinical and autopsy diagnoses can be a source for the epidemiological assessment but not otherwise. So called, epidemiological diagnosis makes mortality rate more discretional and to some degree inflate the numbers of death during COVID-19. The last thing that we need in this coronavirus pandemic which is accompanied by an epidemic of fear.

The World Health Organization allowed China (the second after USA donor) to hide real the COVID-19 outbreak’s numbers in December-January. The cavalierly approach to death statistics is not helpful, moreover counterproductive.

Excerpt from Center for Disease Control and Prevention (CDC) official document on COVID-19

https://www.cdc.gov/coronavirus/2019-nCoV/lab/index.html

The CDC 2019-Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel is a real-time RT-PCR test intended for the qualitative detection of nucleic acid from the 2019-nCoV in upper and lower respiratory specimens (such as nasopharyngeal or oropharyngeal swabs, sputum, lower respiratory tract aspirates, bronchoalveolar lavage, and nasopharyngeal wash/aspirate or nasal aspirate) collected from individuals who meet 2019-nCoV clinical and/or epidemiological criteria (for example, clinical signs and symptoms (the difference between signs and symptoms?) associated with 2019-nCoV infection, contact with a probable or confirmed 2019-nCoV case, history of travel to geographic locations where 2019-nCoV cases were detected (except Antarctica and Arctica in the pandemia?) , or other epidemiologic links (couple examples ?) for which 2019-nCoV testing may be indicated as part of a public health investigation). Testing in the United States is limited to laboratories certified under the Clinical Laboratory Improvement Amendments of 1988 (CLIA), 42 U.S.C. § 263a, to perform high complexity tests. Results are for the identification of 2019-nCoV RNA. The 2019-nCoV RNA is generally detectable in upper and lower respiratory specimens during infection. Positive results are indicative of active infection with 2019-nCoV but do not rule out bacterial infection or co-infection with other viruses. The agent detected may not be the definite cause of disease. Laboratories within the United States and its territories are required to report all positive results to the appropriate public health authorities. Negative results do not preclude 2019-nCoV infection and should not be used as the sole basis for treatment or other patient management decisions. Negative results must be combined with clinical observations, patient history, and epidemiological information.

Bold, italics, and question mark are mine.

Many question marks are in the CDC official document. When the notion of testing, testing, testing became one of the main ways of solving the COVID-19 epidemic, the information of positive or negative 2019-nCoV tests reliability is essential. CDC ought to provide this information without hiding behind general statement.