What We Know So Far (As of March 26, 2020) About COVID-19—An MRT Point of View

Dear Editor,

1. What is the difference among the terms “2019 novel coronavirus,” “SARS-CoV-2,” and “COVID-19” and “COVID-19 Virus”?

• •2019 Novel Coronavirus (2019-nCOV) is a temporary unofficial name of the novel coronavirus that caused the severe acute respiratory syndrome (SARS) outbreak in Wuhan, China, in 2019.
• •SARS-CoV-2: the official name of 2019-nCOV, with nomenclature determined by the International Committee on Taxonomy of Viruses [1]. The “SARS” part of the name refers to the new coronavirus' genetic link to the virus that caused the 2003 SARS outbreak.
• •COVID-19: the disease caused by SARS-CoV-2 and was named by the World Health Organization (WHO) on Feb 11, 2020. “CO” refers to corona, “VI” to virus, and “D” to disease, while “19” designates the year of initial discovery of this disease.
• •COVID-19 refers to the disease while SARS-CoV-2 refers to the virus that causes the disease. However, the WHO sometimes uses the term “COVID-19 virus” for the virus instead of its official name of “SARS-CoV-2.”

2. How does coronavirus affect the human body?

• •SARS-CoV-2 virus binds to angiotensin-converting enzyme II (ACE2) in the alveolae of the lung to gain entry into the host cells [2,3].
• •ACE2 receptors also exist in the heart, kidney, gastrointestinal tract tract, urinary systems [4], and even oral mucosa (especially in the oral tongue) [5].
• •These findings indicate that the organs with high ACE2-expressing cells should be considered as potential high risk for SARS-CoV-2 infection.

3. What symptom should I pay more attention to when I screen a patient?

• •COVID-19 is a lower airway disease. Most common symptoms (viral-related) include fever, coughing (often a dry cough initially, becoming productive later), muscle aches, fatigue, and shortness of breath [6,7].
• •A very recent study suggests that digestive symptoms such as loss of appetite and diarrhea are also common [8].
• •By contrast, upper airway catarrh syndrome, such as running nose or sneezing, is rare in COVID-19 patients [9].
• •According to the WHO, the three most common symptoms for COVID-19 are as follows: fever, tiredness, and dry cough [10].
• •In addition to respiratory symptoms, some COVID-19 patients may exhibit gastrointestinal tract symptoms [8], suggesting unexplained diarrhea may also be considered as a symptom for screening.
• •Recently, the American Academy of Otolaryngology–Head and Neck Surgery also recommended adding “sudden loss of taste or smell” as one of the symptoms for screening of COVID-19 [11].

4. How long does it usually take from infection to recovery?

• •The median time from symptom to recovery is 22 days in survivors and median duration of viral shedding is 20 days (longest 37 days) [12].
• •
  This information is useful for the strategic planning of cancer treatment during the COVID-19 outbreak:

  • •Delaying cancer treatment for COVD-19-positive cancer patients may be feasible for certain cancers, if expected delay is about 4 weeks.

5. How is the virus transmitted?

• •
  COVID-19 virus can spread via respiratory mucus or saliva droplets (coughing and talking), contact with body fluids (e.g., saliva, vomitus, etc.), or from contaminated surfaces [13]. There is no convincing clinical evidence of aerosol spread although in vitro experiments suggested that aerosol spread cannot be fully ruled out [14] (to be discussed later).

  • •
    Differences between respiratory “droplets” and “aerosol” depend on the size of the particles and duration of suspension in the air. Respiratory droplets are generally and arbitrarily defined as > 5 μm in diameter while aerosol particles are considered as ≤5 μm in diameter. These size partitions are still in discussion without complete agreement among groups [15].
• •The most common route of viral transmission is through close contact with infectious secretions (sputum, serum, blood, and respiratory droplets) from a COVID-19 patient.
• •Mucosal surfaces of the face including nose, mouth, and eyes (often forgotten by most people) can all be the entrance portal for the COVID-19 virus.
• •
  Close contact increases risk of viral contraction:

  • •Close contact is defined by the US Centers for Disease Control and Prevention (CDC) as being within 2 meters of a COVID-19 patient for a prolonged period [16].
• •
  Recent investigation shows that the COVID-19 virus may suspend in the air for two to three hours (depending on heat and humidity, and presumably air flow), and exist on external surfaces for more than three days (more stable on plastic and stainless steel than on copper and cardboard) [14].

  • •Exercising good hand hygiene is very important to avoid SARS-CoV-2 entering the eyes, nose, and mouth after touching an infected surface.
  • •As the COVID-19 virus can stay suspended in the air for two to three hours depending on humidity, heat, and airflow [14], WHO advises that “airborne precautions” should be considered for health care professionals (HCPs).
  • •CDC and Public Health Ontario now recommend “airborne precautions” for HCPs when performing aerosol-generating medical procedures for all suspicious or confirmed COVID-19 patients [17,18].

6. What is my risk and how I can minimize the risk of getting infected?

• •HCPs are at high risk because a recent study shows that a substantial proportion of virus spread occurs in the asymptomatic or presymptomatic phase [13].
• •Personal protective equipment (PPE) including eye shielding is an essential first step [19].
• •
  MRTs should follow institutional guidelines for use of PPE and exercise good hand hygiene.

  • •Protect eyes, mouth, and nose with masks, face shields, gowns, gloves.
  • •Avoid having their hands directly touch surfaces.
  • •Practice good hand hygiene.

7. What strategies should departments consider to minimize the risk of intradepartmental COVID-19 transmission?

• •In addition to wearing PPE, practice good hand hygiene, keep your face as far away from your patients as possible, and avoid directly facing a patient's nose and mouth.
• •Develop staff training programs.
• •Screen patients and staff.
• •Disinfection procedures should be established for floor and walls, surfaces, air, and “spills”/disposals [20].
• •
  When talking to a patient, keep your distance (preferably two meters when possible) with patients because we do not know who may be an asymptomatic viral carrier.

  • •Notably studies have shown that the risk of droplet transmission as defined above (i.e., >5 μm in diameter) is very low beyond one to two meters [15].

Radiation therapy:

• •
  A recent publication from China shared specific practice guidelines and treatment workflow for radiotherapy during COVID-19 outbreak [21]:

  • •Health education for patients: informing about the risk of cross-contamination, zoning design, and workflow of radiotherapy during the outbreak.
  • •Zoning: A radiotherapy center should be divided into a “clean zone,” “semi-soiled/semi-contaminated zone,” and “soiled/contaminated zone” with clearly defined protection measures for each zone.
  • •Special consideration should be paid to disinfection of immobilization devices.
• •Strategic planning to prioritize PPE usage within department and organization may be necessary to ensure sustained availability of PPE for staff safety.
• •
  It is important to communicate with the treating Radiation Oncology to triage COVID-19 suspicious or confirmed cases to consider:

  • •Whether postponing/withholding radiotherapy is acceptable
  • •When to restart radiotherapy
  • •Whether to modify the radiotherapy regimen to use a shorter course
• •For a suspicious COVID-19 patient, some cancer centers in Wuhan have asked patients to wear a mask under their thermoplastic mask for head and neck and central nervous system radiotherapy [21].

8. What are some useful disinfection measures for SARS-CoV-2?

• •SARS-CoV-2 viruses are extremely vulnerable to solvent and detergents (e.g., soap) to break down the viral membrane [22]. Washing hands with soap for a sufficient period (>20 seconds) is effective to kill SARS-CoV-2.
• •SARS-CoV-2 viruses are also sensitive to heat (above 60°C) as shown in several experiments because heating could denature proteins [23,24].
• •The viruses can be effectively inactivated by surface disinfection procedures with 62-71% ethanol (alcohol), 0.5% hydrogen peroxide, or 0.1% sodium hypochlorite within one minute [25].
• •Other disinfectants for use against COVID-19 virus are listed via the US EPA website [26]:
• •UV-C light is reported to be effective to kill >99% of other coronavirus (MERS-CoV and SARS-CoV) in 10 minutes [27] and has been used in some Chinese hospitals as a disinfection method [20].

9. What is the incubation period for COVID-19?

• •Generally, the median incubation period for COVID-19 is approximately 5.1 days (mean 5.5 days)
• •In 97.5% of infected persons, symptoms appear within 12 days [28].
• •Screening for a travel history of 14 days and current symptoms will catch most symptomatic COVID-19 patients.
• •However, emerging evidence suggests that a proportion of viral transmission could occur before symptom onset [[29], [30], [31]].
• •Some small studies suggested that asymptomatic viral carriers may be infectious for up to three weeks [29].

10. How contagious is the COVID-19 Virus compared to other coronaviruses?

• •The transmutability of a virus is measured using the “reproduction number” (R0). This is measured by the number of individuals affected by one viral carrier. The higher the R0, the more transferable the virus is and the higher the risk for rapid spread.
• •The WHO initial estimation of R0 for SARS-COV-2 is 1.4-2.5 [2].
• •However, recent review shows that the mean R0 for SARS-COV-2 is 3.3, and a median of 2.8 [32].
• •There are at least two strains of SARS-CoV-2: S type (the older version) and L type (the newer strain). L type seems more aggressive and the virus spread is more rapid [33].

11. How can MRTs protect their family?

• •Consider using hospital-issued surgical scrubs at work and leaving them at work for hospital wash.
• •Do not wear scrubs on public transportation and at home.
• •Leave your coat and shoes at the door, away from living areas.
• •
  For disinfection, CDC recommends dilute household bleach solutions, alcohol solutions with at least 70% alcohol, and most common EPA-registered household disinfectants.

  • •Five tablespoons (1/3rd cup) bleach per gallon of water or
  • •Four teaspoons bleach per quart of water
• •Separate the dirty scrubs from normal clothing.
• •Launder items using the hottest appropriate water setting.

12. What are controversies about some medications during the COVID-19 outbreak?

• •Ibuprofen and acetaminophen: France has reported that nonsteroidal anti-inflammatory medication (NSAIDs), such as ibuprofen, might aggravate symptoms of COVID-19, hence suggesting avoidance of their use. However, the Food and Drug Administration (FDA) and WHO feel that more evidence is needed and have not recommended avoiding ibuprofen to treat COVID-19 symptoms.
• •ACE inhibitors or ARBs: Several researchers observed an association between ACE inhibitors and severity of COVID-19 [6] and proposed a hypothesis that ACE inhibitors could act as a potential risk factor for COVID-19 by upregulating ACE2 receptor [34,35]. However, others believe that the current data have not proven its causation and recommend against cessation of this anti-hypertension medication [36].

13. What is the effective treatment for COVID-19?

• •Mostly supportive care
• •Two drugs recently received FDA approval for “compassionate use” (i.e., “expanded access”): chloroquine/hydroxychloroquine and remdesivir for treatment of COVID-19 based on some preliminary promising clinical data [[37], [38], [39]], but their ultimate value remains uncertain.

14. When an individual has recovered from SARS-CoV-2, could he/she get reinfected?

• •A recent animal model experiment (on monkeys) shows that primary SARS-CoV-2 infection could protect an individual from subsequent infection [40].
• •The duration of the putative protection remains unknown.