Facts about the Sars-CoV-2 Coronavirus and Predictions for Dentistry

Soon, each of us will need to answer questions from our patients and friends about the ongoing pandemic. We need to understand details about the COVID-19 contagion. Being the most up-to-date in our knowledge may reassure our patients that we have been keeping up with the facts and the latest preventive measures. We should be one of our patients’ best resources to understand and explain this viral infection. For the most recent information and statistics go to https://www.cdc.gov/coronavirus/2019-ncov/cases-updates/cases-in-us.html

History of the Outbreak

A clarification is needed early in this discussion. Sars-CoV-2 is the name of the virus and COVID-19 is the name of the disease in humans that the virus causes. Sars-CoV-2 is a highly contagious nosocomial viral agent (rapid velocity transmission). The current COVID 19 outbreak is both similar and different than earlier pandemic acute respiratory syndromes like Sars-CoV-1 and MERS CoV-2 (Middle East Respiratory Syndrome) outbreaks. Sars-CoV-2 is believed to have been initiated through zoonotic transmission (from animal to human). The virus spread from the city of Wuhan to all of China in 30 days. It is believed to have started sometime around October 2019. As of March 27, 2020, the United States infection rate had exceeded the original Chinese outbreak figures. China, South Korea and Singapore, as of this writing, seem to have brought the disease under control. (https://www.cdc.gov/coronavirus/2019-ncov/downloads/Wang-Comment-outbreak-of-global-health-concern-Lancet-1-24-2020.pdf).

How it Works

While it is highly transmissible, the virus itself is easy to kill. It’s what is referred to as an encapsulated RNA virus and current statistics (March,.2020) have not conclusively determined its relative fatality rate comparing it to previous outbreaks of Sars-CoV-1 and MERS-CoV-2.  The majority of the fatalities are in our elderly population and/or in patients with pre-existing underlying chronic diseases such as cardiovascular disease, diabetes mellitus, hypertension and chronic obstructive pulmonary disease (COPD). It should be noted however that there are plenty of exceptions with records of young people suffering and dying from this infection. The second most vulnerable group susceptible to this contagion is healthcare workers. This may be because initially, healthcare workers treating COVID-19 were not using the optimal PPEs but it may be a sign that science does not currently have a complete understanding of how this virus is transmitted.

The physical microscopic geometry of this virus has a hook-like spike attachment apparatus that seems to attach to a cell membrane’s ACE2 binding site (cell membranes typically have specific binding sites to allow specific chemicals and hormones to cross the cell membrane barrier) The ACE-2 cell membrane receptor site is believed to be involved in blood pressure regulation. Perhaps this explains why people with heart disease, diabetes and high blood pressure are at higher risk with this disease? After the virus attaches to a lung cell it injects its RNA content and takes over the cell’s Golgi apparatus to reproduce itself until the cell lyses.  The lysed viral contents spill out and infect other neighboring cells. Once the body begins fighting the virus being manufactured within the lung cells, serious fibrotic lesions form within the lung which can result in severe lung damage and death (e.g. acute respiratory distress syndrome and septic shock)  Ventilators are needed for the critically infected to overcome the lung damage and lack of oxygenation to the body’s vital organs.

Pennsylvania Commonwealth microbiologist Kerry Pollard performs a manual extraction of the coronavirus inside the extraction lab at the Pennsylvania Department of Health Bureau of Laboratories on Friday, March 6, 2020.

Diagnosing, Testing and Reporting

Confirmation of the infection has been reported to be possible using more than one method. Some radiologists believe the viral infection leaves a distinct ground- glass pattern in the lungs and can be diagnosed from chest x-rays. ( https://www.cdc.gov/coronavirus/2019-ncov/hcp/pediatric-hcp.htm). The definitive agreed method of diagnosis requires nucleic acid amplification testing of respiratory tract samples (throat and/or nasal swabs) Most of the current diagnosis, however, is relying on symptoms like fever and dry cough because the magnitude of the infection is beyond current logistical capabilities to test for the virus. Scientists believe somewhere between 50 to 60% of those carrying the virus may have mild to insignificant symptoms (Resource Nature Mar 20). It is conjectured that the earliest sign of the disease may be the absence of the ability to taste and smell, based on recovered patient interviews. Replication of the Sars-CoV-2 virus is suggested in a study to occur in the throat independently from the lung which is different than Sars-CoV-1. This may give scientific credence to using zinc gluconate lozenges prophylactically to help battle the virus before it reaches the lung tissues of unsuspecting viral victims. (https://www.uchealth.org/today/zinc-could-help-diminish-extent-of-covid-19/)   Humans undergoing attack by this contagion produce antigens; this may be an avenue of testing for those who have recovered from infection and those who may be in the initial phases of COVID-19 infection. The verdict on using antigen testing is not fully accepted because of conflicting studies concerning what phases in the pathologic sequence of infection a patient may test positive for COVID-19 using antigen testing. Ultimately antigen testing may be adjunctive to other diagnostic methods.

As we mentioned earlier, co-morbidities raise the risk of dying from COVID-19. From the CDC’s analysis of China’s information, the following statistics were derived, using stats from 44,672 patients infected. It was found that the fatality rate in patients who reported no other health conditions was 0.9%. It was 10.5% for those with cardiovascular disease, 7.3% for those with diabetes, 6.3% for people with chronic respiratory diseases such as COPD, 6.0% for people with hypertension, and 5.6% for those with cancer. The most common symptoms of infection were fever (86-97%), followed by cough (95%) https://www.ncbi.nlm.nih.gov/pubmed/32173574, and Clinical Infectious Diseases, ciaa247, https://doi.org/10.1093/cid/ciaa247

Stopping the Outbreak

 Infection with Sars-CoV-2 is not a death sentence and the majority of people will survive this pandemic. The distinct issue with this viral infection is that people may be infected showing very few signs of having contracted the virus while spreading it around the environment and infecting other people. Because the virus is an encapsulated RNA virus it can be killed by most quality disinfection agents used in routine dental office disinfection regimens. Being meticulous in wiping surfaces is important as the virus can survive on smooth surfaces for several days. It can also be carried by aerosol dispersion into rooms. Aerosol dispersion is the most likely reason that healthcare providers have become the second most vulnerable population group to this viral outbreak. More study is needed to conclude the most reliable methods of disinfection and decontamination. 

The Post-Pandemic Future

All of the information presented above comes from reputable resources like CDC, University Minnesota, ADA, UC Health and Nature. Now that we have discussed the facts as we currently know them my discussion will move to an opinion discussion of what the future is likely to hold for our dental profession. I request the following be read as an educated opinion piece, intended to be thought-provoking. Don’t get mad, but do mentally push back and question every aspect of the discussion to either validate or refute the conclusion. Mostly put your mind to work, but if you agree with me, use your emotions to contact our elected officials and advocate for rapid testing in our communities to bring our lives back to a more normal manageable place and protect us from future viral pandemics. 

Things will not be the same as they were in the good old days circa Jan 1, 2020.  The ongoing contagion has highlighted vulnerabilities and weaknesses in our infection control standards.  We must upgrade our standards to assure the safety of ourselves, our families, our staff and our patients. As I write this portion of the article I sincerely hope that I will be wrong in some of my perceptions of our future practice environment. 

Shelter-in-place is a useful tool to slow the spread of the Sars-CoV-2 virus, but until a vaccine is approved (estimated to be 12 to 18 months) for widespread use, the shelter- in- place strategy will only slow the rate of spread. Shelter- in- place allows our healthcare systems to avoid being completely overwhelmed. To obtain the highest degree of control for the spread of the virus and avoid complete economic collapse, we must find a way that allows healthy people to go back to work while continuing to control the infection. Shelter- in -place in conjunction with identifying viral carriers is the only way to stop continual spread beyond sequestering our entire population. The WHO (World Health Organization) has called for testing along with shelter- in -place. Diagnostic testing for COVID-19 is critical to tracking the virus, understanding epidemiology, informing case management and suppressing transmission. https://www.who.int/docs/default-source/coronaviruse/situation-reports/20200323-sitrep-63-covid-19.pdf?sfvrsn=d97cb6dd_2 “ In the US, rapid testing of at least high- risk communities (New York, California, Washington and Louisiana) will allow us to identify those carrying the virus in our population (some of whom show little or no symptoms). Identification and removal of viral carriers from circulating, and providing the necessary healthcare support are needed to stop transmissions of the virus. The process will involve continually testing and removing carriers from spreading contagion while the rest of our population can get back to work. This is the only way to avoid complete economic collapse inevitable with a prolonged shutdown of our country. 

Just another day at the office in the post-pandemic health care world.

Dentistry After COVID-19

Dentistry is likely to prove particularly problematic because the known characteristics concerning the spread of this virus uniquely conflict with the aspects of what our profession is all about. We are continually working in the presence of our patients’ exhaust and the instruments we use cause aerosols that can project the Sars-CoV-2 virus into the atmosphere of our treatment rooms and office spaces. Not knowing which patients may be carrying this virus might be considered a form of statistical gambling and likely will be judged as an unacceptable risk by our regulatory agencies. If we are to get back to work, consider these logistics and possibilities:

Ideally, testing each patient until there is a vaccine, using a rapid testing method would allow us to prevent spreading this virus within our office. Knowing that a patient is free from viruses and that the office personnel are free of the virus allows everyone to interact within our office with minimal fear of getting sick from the experience. This is the closest scenario to life getting back to normal in our dental office.

If rapid testing for the virus turns out to be impossible, we will likely find other options less tenable, but there may be two other paths. 

Path 1 is to understand we may not be allowed to go back to work except to treat emergencies until a vaccine is produced.  This could take 18 months. Some worker groups may be allowed to go back to work, but it is unlikely that will be the case for dentistry when we consider the logistics of what we do and how the virus infects people. 

Path 2 is to be as strategic as possible and hopefully, CDC and OSHA will recognize how to minimize risk or accept some risk? Will our staff, our patients and families feel the same? 

In Path 2 we meticulously review patient health histories and the patient’s dental needs. We do not treat patients of the highest risk. Patients older than 60 and specifically those who have heart disease, diabetes, high blood pressure, cancer treatment and compromised immune systems will only be treated in more isolated areas for emergency dental problems. Patients who have taken meds for bone density (bisphosphonates) will be particularly problematic as both emergency care and preventive care will have risks.  

Our patients will sign a disclaimer recognizing serious precautions have been taken to prevent viral spread, but should they be a viral carrier they may jeopardize others while seeking care. 

Our staff will wear hair nets or hair caps, N95 masks, outer gowns and face shields. As should always be done, the majority of our outfits will be changed between each patient (outer gown, shields, masks of course and hairnets).  We will schedule more time (logistical distance) between our patients to properly decontaminate our rooms and our adjunctive treatment gear (note I did not use the term disinfect, but decontaminate because we have to account for aerosols as well as the usual surfaces)  

Ideally, each operatory will be retrofitted to become negative pressure rooms maintaining their own generated atmospheres. If that is not logistically feasible,  we will resort to using isolating methods with UV Charcoal HEPA Filter air purifiers. This can be augmented with UV germicidal lamps to deactivate any viral aerosols in the air. 

Patients will not be allowed to just hang out in reception areas. Some offices will have patients wait in their car until notified by phone to come into the office.  Contact with our front office personnel will be minimized. Front administrative staff in contact with patients will wear masks, gloves and shields. 

During treatment, methods will be routinely implemented like rubber dam or isolite isolation mouth props to maximize high-speed evacuation of aerosol producing liquids. Perhaps shoulder- to- head patient chair shields (chair tents) will be devised for our patient to lie inside, helping to confine the room aerosol sprays. Hygiene will not use sonic or ultrasonic scaling.

Current CDC tests will not be fast enough for use in the dental office of the future.

The Need for Rapid Testing

Rapid testing can make some of these protocols mentioned above less draconian (like negative pressure rooms and chair tents) by eliminating carriers of the virus from our active treatment environment.  Weaknesses in our disinfection protocols are apparent and because we have learned from this experience, we will still adopt some of the strategies mentioned above to upgrade our infection control strategies. Rapid testing systems for viral infections may be costly, but communities equipped with this technology will not face the devastation of a viral pandemic again in our lifetime. The mobilization to make rapid testing a community reality will be a form of community vaccination against the catastrophic effects of emerging viral contagions that are likely to occur again in our future world. 

Please take the time to write our Senators, Congressmembers and our President. Let’s mobilize our country to maximize its efforts to make rapid viral testing a reality. This will benefit our country now and in the future and it will allow our communities to get back to work and dentistry to get back to helping our patients maintain optimal oral and systemic health.

 

Robert Shorey, DDS
Editor

About the Author

Dr. Robert Shorey is a graduate of the University of Southern California School of Dentistry. After practicing in the Sacramento/Placer County area for 25 years, he relocated to Morgan Hill where he practices today.

He has a strong interest in digital technology and has authored multiple technology articles as well as lectured on the state and national levels. Over his career, he has incorporated new technologies into his practice and believes strongly in preventive care and the whole health and education of his patients.

Dr. Shorey is an active participant in dental leadership receiving the President’s Award in 1998 for contributions to his local dental society. He is a member of the society’s Board of Directors, a delegate to the California Dental Association, chairman of the Midwinter Dental Conference for Continuing Dental Training and Education, a dental journal Editor and Guest Editor for the CDA as well as a lecturer on new clinical dental technologies. Dr. Shorey served as President of the Sacramento District Dental Society in 2008 and is currently on the Communications Committee and CE Committee of the Santa Clara County Dental Society.

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