You are leaving Medscape Education
Cancel Continue
Log in to save activities Your saved activities will show here so that you can easily access them whenever you're ready. Log in here CME & Education Log in to keep track of your credits.
 

CME / ABIM MOC / CE

COVID-19: What Do We Know About Transmission Routes and Surface Survival?

  • Authors: CME Authors: Laurie Barclay, MD and Esther Nyarko, PharmD
  • CME / ABIM MOC / CE Released: 3/29/2020
  • Valid for credit through: 3/29/2021
Start Activity

  • Credits Available

    Physicians - maximum of 0.50 AMA PRA Category 1 Credit(s)™

    ABIM Diplomates - maximum of 0.50 ABIM MOC points

    Nurses - 0.50 ANCC Contact Hour(s) (0 contact hours are in the area of pharmacology)

    Pharmacists - 0.50 Knowledge-based ACPE (0.050 CEUs)

    IPCE - 0.50 Interprofessional Continuing Education (IPCE) credit

    You Are Eligible For

    • Letter of Completion
    • ABIM MOC points

Target Audience and Goal Statement

This article is intended for primary care clinicians, clinicians of all specialties, family medicine practitioners, nurses, public health officials, and other members of the healthcare team involved in prevention, containment or management of coronavirus disease (COVID-19).

The goal of this activity is to provide medical news to primary care clinicians and other healthcare professionals in order to enhance patient care.

Upon completion of this activity, participants will be able to:

  • Describe updates on the clinical course of COVID-19, including transmission routes and time on surfaces that the virus remains viable, according to recent evidence
  • Determine epidemiological and other similarities of COVID-19 to other coronavirus, according to recent evidence, and implications of these similarities for prevention and containment strategies
  • Identify implications for the healthcare team


Disclosures

As an organization accredited by the ACCME, Medscape, LLC, requires everyone who is in a position to control the content of an education activity to disclose all relevant financial relationships with any commercial interest. The ACCME defines "relevant financial relationships" as financial relationships in any amount, occurring within the past 12 months, including financial relationships of a spouse or life partner, that could create a conflict of interest.

Medscape, LLC, encourages Authors to identify investigational products or off-label uses of products regulated by the US Food and Drug Administration, at first mention and where appropriate in the content.


CME Authors

  • Laurie Barclay, MD

    Freelance writer and reviewer, Medscape, LLC

    Disclosures

    Disclosure: Laurie Barclay, MD, has disclosed no relevant financial relationships.

  • Esther Nyarko, PharmD

    Associate Director, Accreditation and Compliance, Medscape, LLC

    Disclosures

    Disclosure: Esther Nyarko, PharmD, has disclosed no relevant financial relationships.

Editor

  • Hazel Dennison, DNP, RN, FNP, CPHQ, CNE

    Associate Director, Accreditation and Compliance , Medscape, LLC

    Disclosures

    Disclosure: Hazel Dennison, DNP, RN, FNP, CPHQ, CNE, has disclosed no relevant financial relationships.

CME Reviewer

  • Esther Nyarko, PharmD

    Associate Director, Accreditation and Compliance, Medscape, LLC

    Disclosures

    Disclosure: Esther Nyarko, PharmD, has disclosed no relevant financial relationships.

Nurse Planner

  • Amy Bernard, MS, BSN, RN-BC, CHCP

    Director, Accreditation and Compliance, Medscape, LLC

    Disclosures

    Disclosure: Amy Bernard, MS, BSN, RN-BC, CHCP, has disclosed no relevant financial relationships.

Medscape, LLC staff have disclosed that they have no relevant financial relationships.


Accreditation Statements



In support of improving patient care, Medscape, LLC is jointly accredited by the Accreditation Council for Continuing Medical Education (ACCME), the Accreditation Council for Pharmacy Education (ACPE), and the American Nurses Credentialing Center (ANCC), to provide continuing education for the healthcare team.

This activity was planned by and for the healthcare team, and learners will receive 0.50 Interprofessional Continuing Education (IPCE) credit for learning and change.

    For Physicians

  • Medscape, LLC designates this enduring material for a maximum of 0.50 AMA PRA Category 1 Credit(s)™ . Physicians should claim only the credit commensurate with the extent of their participation in the activity.

    Successful completion of this CME activity, which includes participation in the evaluation component, enables the participant to earn up to 0.50 MOC points in the American Board of Internal Medicine's (ABIM) Maintenance of Certification (MOC) program. Participants will earn MOC points equivalent to the amount of CME credits claimed for the activity. It is the CME activity provider's responsibility to submit participant completion information to ACCME for the purpose of granting ABIM MOC credit.

    Contact This Provider

    For Nurses

  • Awarded 0.50 contact hour(s) of continuing nursing education for RNs and APNs; none of these credits is in the area of pharmacology.

    Contact This Provider

    For Pharmacists

  • Medscape, LLC designates this continuing education activity for 0.50 contact hour(s) (0.05 CEUs) (Universal Activity Number JA0007105-0000-20-043-H01-P).

    Contact This Provider

For questions regarding the content of this activity, contact the accredited provider for this CME/CE activity noted above. For technical assistance, contact [email protected]


Instructions for Participation and Credit

There are no fees for participating in or receiving credit for this online educational activity. For information on applicability and acceptance of continuing education credit for this activity, please consult your professional licensing board.

This activity is designed to be completed within the time designated on the title page; physicians should claim only those credits that reflect the time actually spent in the activity. To successfully earn credit, participants must complete the activity online during the valid credit period that is noted on the title page. To receive AMA PRA Category 1 Credit™, you must receive a minimum score of 75% on the post-test.

Follow these steps to earn CME/CE credit*:

  1. Read the target audience, learning objectives, and author disclosures.
  2. Study the educational content online or printed out.
  3. Online, choose the best answer to each test question. To receive a certificate, you must receive a passing score as designated at the top of the test. We encourage you to complete the Activity Evaluation to provide feedback for future programming.

You may now view or print the certificate from your CME/CE Tracker. You may print the certificate but you cannot alter it. Credits will be tallied in your CME/CE Tracker and archived for 6 years; at any point within this time period you can print out the tally as well as the certificates from the CME/CE Tracker.

*The credit that you receive is based on your user profile.

CME / ABIM MOC / CE

COVID-19: What Do We Know About Transmission Routes and Surface Survival?

Authors: CME Authors: Laurie Barclay, MD and Esther Nyarko, PharmDFaculty and Disclosures

CME / ABIM MOC / CE Released: 3/29/2020

Valid for credit through: 3/29/2021

processing....

Note: This is the eleventh of a series of clinical briefs on the coronavirus outbreak. The information on this subject is continually evolving. The content within this activity serves as a historical reference to the information that was available at the time of this publication. We continue to add to the collection of activities on this subject as new information becomes available.

Clinical Context

In addition to severe acute respiratory syndrome-associated coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19, is turning out to be the third highly pathogenic human coronavirus that has emerged in the last 2 decades.[1] The exponential rise in outbreak confirmed cases and deaths is indicative of human-to-human transmission by the virus.

On March 11, World Health Organization (WHO) Director-General Tedros Adhanom Ghebreyesus officially declared the COVID-19 outbreak a pandemic.[2] Although coronaviruses have caused outbreaks in which transmission can occur by environmental contamination, the mode of transmission and extent of environmental contamination are unknown, especially for SARS-CoV-2.[3] Community spread, even to persons with no known history of travel to endemic regions or of exposure to ill persons, suggests transmission by viable droplets on environmental surfaces.

Epidemiological and other similarities of SARS-CoV-2 to other coronaviruses may facilitate identifying viable preventive strategies for this most recently detected pathogen. Clarifying transmission routes and duration of viability of viruses on exposed surfaces is essential for containment of the COVID-19 outbreak, which as of March 26 had caused more than 400,000 confirmed cases worldwide and more than 20,000 deaths globally,[4] with continued rise.

Although several drugs are being used and under investigation to treat COVID-19, early containment and prevention of further spread is critical and crucial to stopping this pandemic.

Study Synopsis and Perspective

Because information is still lacking on the transmissibility of COVID-19 from contaminated environmental surfaces and objects, studies looking at decontamination are important. It is known that human coronaviruses can remain infectious on surfaces for a number of days. It is also known that coronavirus is transmitted via human-to-human contact, and one key mechanism of this could be through self-inoculation from contaminated surfaces (eg, self-inoculation may occur through failure to observe proper hand hygiene or infection control practices). Frequent face touching during seasonal outbreaks has the potential to be a mechanism of contamination and transmission. For many of us, touching the face seems to be an unconscious, natural reaction.

In exploring the hands as a means for transmission of infections, Yen Lee Angele Kwok, PhD, MBBS, MPH, MHM, and colleagues looked at behavioral characteristics involving medical students at the University of New South Wales in a longitudinal observational study, which was published in the February 1, 2015 issue of the American Journal of Infection Control.[5] Researchers looked at face-touching behavior as a potential for virus transmission and self-inoculation.

The study showed that, on average, of 26 students, each touched their face 23×/h. Of all face touches, 44% (1024/2346) involved contact with a mucous membrane whereas 56% (1322/2346) of contacts involved nonmucosal areas. Of mucous membrane touches observed, 36% (372/1024) involved the mouth, 31% (318/1024) involved the nose, 27% (273/1024) involved the eyes, and 6% (61/1024) were a combination of these regions.

Contamination of frequent touch surfaces is a potential source of viral transmission; however, that is not thought to be the main route of transmission for COVID-19.[6]

According to the Centers for Disease Control and Prevention (CDC), more information is needed concerning the spread of the virus; however, as with other human coronaviruses, spread is thought to occur through person-to-person contact (within 6 feet) via respiratory droplets. Having direct contact with infectious secretions (eg, sputum, serum, blood, respiratory droplets) from a patient with COVID-19 is known to spread the virus as well.

In a recent research letter published in JAMA,[7] Dawei Wang, MD, and colleaguesshared research investigating the presence of SARS-CoV-2 in specimens obtained from sites other than the nasopharyngeal swab, which is the routine method used to confirm clinical diagnosis of COVID-19. The researchers obtained data from January 1 through February 17, 2020 at 3 hospitals in the Hubei and Shandong provinces and Beijing, China, with 1070 specimens collected from 205 infected patients. The mean age was 44 (range, 5-67) years; 68% were male; 19% of patients had severe illness; most presented with fever, dry cough, and fatigue. Positive rates for SARS-CoV-2 were 93% in bronchoalveolar lavage fluid, 72% in sputum, 63% in nasal swabs, 46% in fibrobronchoscope brush biopsy, 32% in pharyngeal swabs, 29% in feces, 1% in blood, and 0 in urine. The investigators recovered live SARS-CoV-2 in stool from 2 patients who did not have diarrhea. According to their findings, the investigators concluded that lower respiratory tract samples most often tested positive for SARS-CoV-2 but that feces also detected the live virus, suggesting that SARS-CoV-2 may be transmitted via the fecal route.

Sean Wei Xiang Ong, MBBS, of the National Center for Infectious Diseases, Singapore, and colleagues further investigated the fecal route of contamination by obtaining sampling data from 3 patients housed in airborne isolation rooms dedicated to SARS-CoV-2 in Singapore. Study results were published online March 4 on the JAMA website.[3] The investigators took surface samples from 26 sites in the isolation room, anteroom, and bathroom for each of the patients while they were still symptomatic. They sampled those areas twice on days 4 and 10 of illness for the first patient, days 8 and 11 for the second patient, and day 5 for the third patient and also sampled physicians’ personal protective equipment (PPE) before leaving the patients’ room.


Ong SWX, et al.[3]

All PPE samples tested negative except for the front of one shoe.

"The risk of transmission from contaminated footwear is likely low, as evidenced by negative results in the anteroom and corridor," they wrote.

Air outlet fans and other room sites also tested positive for SARS-CoV-2, although an anteroom, a corridor, and most PPE worn by healthcare providers (HCPs) tested negative.

Mr Ong and his coauthors pointed out that as air exhaust outlets tested positive, it suggests that virus-laden droplets could be "displaced by airflows" and end up on vents or other equipment.

Taken together, these findings suggest a "need for strict adherence to environmental and hand hygiene" to combat significant environmental contamination through respiratory droplets and fecal shedding, Mr Ong and colleagues wrote.

These findings stress the importance of following CDC recommendations on environmental cleaning and disinfection.[8] The CDC provides guidance for cleaning and disinfection after persons suspected/confirmed to have COVID-9 have been in a facility.

One limitation for the study by Mr Ong and colleagues is the small sample size; however, given the limited amount of information we have on the characterization of COVID-19, it provides important and useful insight on the importance of appropriate environmental disinfecting and decontamination.

To better understand SARS-CoV-2, the virus that causes COVID-19, researchers have been comparing it to SARS-CoV, which causes severe acute respiratory syndrome (SARS). Current research shows similarity between the two human coronaviruses and provides more supporting data emerging on surface survival for COVID-19.

A recent National Institutes of Health (NIH) study from the National Institute of Allergy and Infectious Diseases’ Montana facility at Rocky Mountain Laboratories evaluated the stability of the 2 coronaviruses.

In a letter to the editor of the New England Journal of Medicine,[9] published online March 17, lead investigators Neeltje van Doremalen, PhD, and Trenton Bushmaker, BSc, and colleagues shared their research looking at the aerosol and surface stability of SARS-CoV and SARS-CoV-2. They evaluated the aerosol stabilities of both viruses for up to 3 hours in aerosols and up to 7 days on different surfaces (polypropylene, plastics, stainless steel, copper, and cardboard). Study results showed that both viruses share similarities in stability and have similar half-lives in aerosols (~ 2.7 hours) and show long viability on stainless steel and polypropylene compared with copper or cardboard (~ 13 hours on steel and ~ 16 hours on polypropylene).

The authors outlined differences between SARS-CoV and SARS-CoV-2. Their results showed the following surface stability:

Surface

Time

Aerosols

≤ 3 hours

Copper

≤ 4 hours

Cardboard

≤ 24 hours

Plastic

≤ 2 to 3 days

Stainless steel

≤ 2 to 3 days

van Doremalen, et al.[9]

They concluded that the ability of the virus to remain on fomite surfaces (ie, clothes, utensils, furniture) for hours and even days is possible. Their findings inferred that COVID-19 virus SARS-CoV-2 has a longer half-life on cardboard than SARS-CoV. A limitation cited is that cardboard tends to have a noisier surface (meaning there was more variation in the experiment, resulting in a larger standard error) than other surfaces tested, so careful interpretation is needed.

 
 

van Doremalen, et al.[9]

In the stability study, the 2 viruses behaved similarly. The researchers simulated healthcare conditions by applying viruses to multiple surfaces maintained at 21°C to 23°C and 40% relative humidity over 7 days and investigated how long each virus remained infectious on those surfaces. Researchers compared the 2 viruses’ in 10 experimental conditions in 5 environmental conditions (aerosols, copper, cardboard, plastic, stainless steel). Summary of findings below:

Surface

SARS-CoV

Time Viable

SARS-CoV-2

Time Viable

Aerosols

≤ 3 hours

≤ 3 hours

Copper

≤ 4 hours

≤ 4 hours

Cardboard

≤ 8 hours

≤ 24 hours

Plastic

≤ 72 hours

≤ 72 hours

Stainless steel

≤ 48 hours

≤ 72 hours

Authors noted an exponential decay in virus titer across all experimental conditions. The 2 viruses bore similarities in that they had similar half-lives in aerosols (1.09 [95% CI: 0.64, 2.64] hours for SARS-CoV-2 and 1.18 [95% CI: 0.78, 2.43] hours for SARS-CoV). They bore similar half-lives on copper surfaces as well. SARS-CoV-2 was noted to have a longer half-life on cardboard than SARS-CoV. Both viruses showed longest viability on stainless steel and plastic. From these results, differences between both viruses were small except for those on cardboard, where there was a notable difference as pointed out by the authors.

As with the previous study by Ong and colleagues,[3] authors showed the similarity in viability of the 2 viruses on multiple surfaces.[9] They both reached the same conclusion that transmission of COVID-19 from aerosol and other surfaces is possible, as the virus (SARS-CoV-2) remains on these surfaces from a couple of hours to days (depending on inoculum shed, according to the NIH study).[3,9]

Nonetheless, the question remains as to why SARS-CoV-2 seems to be resulting in significantly more cases compared with its predecessor.

Current and emerging evidence suggests that asymptomatic carriers of the SARS-Co-V2 may be spreading it unknowingly before recognizing symptoms or receiving a confirmed diagnosis. The NIH researchers pointed out that this would make disease control measures less effective against this virus as compared with SARS-C0V. The question remains whether its stability in aerosols and on other surfaces is contributing to the widespread outbreak occurring in the community.

An analysis by Günter Kampf, MD, and colleagues, reviewed 22 studies on all coronaviruses, including SARS and Middle East respiratory syndrome (MERS), and their ability to remain on inanimate surfaces. The analysis, with results published in the March issue of the Journal of Hospital Infection,[1] also examined the use of biocidal agents as chemical disinfection to inactivate the virus. The researchers also confirmed that both SARS and MERS can remain on metal, glass, and plastic for up to 9 days and showed that surface disinfection with solutions such as 62% to 71% ethanol, 0.5% hydrogen peroxide, or 0.1% sodium hypochlorite within one minute can eradicate the presence of the virus. Other biocidal agents such as 0.05% to 0.2% benzalkonium chloride or 0.02% chlorhexidine digluconate were shown to be less effective.

Current CDC guidance[8] advocates for the routine cleaning and disinfection procedures in healthcare settings, including those patient-care areas in which aerosol-generating procedures are performed. The CDC recommends using products with Environmental Protection Agency (EPA)-approved emerging viral pathogens' claims for use against SARS-CoV-2. Management of laundry, food service utensils, and medical waste should also be performed in accordance with routine procedures.

Funding for this study came from the National Medical Research Council and DSO National Laboratories, both in Singapore. Ong and colleagues reported no conflicts of interest.

Study Highlights

  • A research letter in JAMA describes surface environmental contamination by SARS-CoV-2 from a patient symptomatic from COVID-19.[3]
  • 3 symptomatic patients at the dedicated SARS-CoV-2 outbreak center in Singapore in airborne infection isolation rooms had surface environmental samples taken at 26 sites from January 24 to February 4, 2020.[8]
  • These were tested for SARS-CoV-2 using specific real-time reverse transcriptase-polymerase chain reaction (RT-PCR).
  • Although 2 patients had negative test results from samples taken after routine cleaning, the third, whose samples were collected before routine cleaning, had positive results for SARS-CoV-2 in 87% of 15 room sites, including air outlet fans, and in 60% of 5 toilet sites.
  • Samples from an anteroom, a corridor, and most PPE worn by HCPs tested negative.
  • This patient had upper respiratory tract involvement without pneumonia and had 2 positive stool samples for SARS-CoV-2, despite the absence of diarrhea.
  • In spite of limitations of this study, including lack of viral culture and small sample size, the investigators concluded that this patient with mild upper respiratory tract involvement produced extensive environmental contamination.
  • Positive toilet bowl and sink samples suggest viral shedding in stool as a potential route of transmission.
  • After room cleaning, samples were negative, suggesting that current decontamination measures are sufficient.
  • Further studies are required to confirm these preliminary results.
  • Still, the findings of significant environmental contamination by patients with SARS-CoV-2 through respiratory droplets and fecal shedding suggests the environment as a potential medium of transmission and supports the need for strict adherence to environmental and hand hygiene.
  • An analysis of 22 studies showed that human coronaviruses, including SARS, MERS, and endemic human coronaviruses, can persist on metal, glass, plastic, and other inanimate surfaces for up to 9 days.[1]
  • Nonetheless, virus droplets on surfaces can be inactivated within 1 minute by surface disinfection with 62% to 71% ethanol, 0.5% hydrogen peroxide, or 0.1% sodium hypochlorite.
  • A second research letter in JAMA describes detection of SARS-CoV-2 in different types of clinical specimens, also suggesting fecal shedding as a potential route of transmission.[7]
  • From January 1 through February 17, 2020, at 3 hospitals in the Hubei and Shandong provinces and Beijing, China, researchers collected 1070 specimens from 205 patients with COVID-19.
  • Mean age was 44 (range, 5-67) years; 68% were male; 19% of patients had severe illness; most presented with fever, dry cough, and fatigue.
  • Positive rates for SARS-CoV-2 were 93% in bronchoalveolar lavage fluid, 72% in sputum, 63% in nasal swabs, 46% in fibrobronchoscope brush biopsy, 32% in pharyngeal swabs, 29% in feces, 1% in blood, and 0% in urine.
  • Live SARS-CoV-2 was recovered in stool from 2 patients who did not have diarrhea.
  • According to their findings, the investigators concluded that lower respiratory tract samples most often tested positive for SARS-CoV-2 but that the live virus was also detected in feces, suggesting that SARS-CoV-2 may be transmitted via the fecal route.
  • As a small percentage of blood samples had positive PCR findings, infection may sometimes be systemic.
  • Respiratory and extra respiratory routes of SARS-CoV-2 transmission may help explain the rapid spread of COVID-19.
  • Testing specimens from multiple sites may improve sensitivity and lower false-negative testing rates.
  • The findings are consistent with those of 2 smaller studies, in which SARS-CoV-2 was detected in anal or oral swabs and blood from 16 patients in Hubei Province[10] and in throat swabs and sputum from 17 confirmed cases.[11]
  • Study limitations include lack of detailed clinical information from some patients, precluding correlation of positive sites with symptoms or disease course, and small sample size, warranting further study.
  • Similarities between SARS-CoV-2 and other coronavirus infections may facilitate identification of optimal prevention strategies and potential targets for antiviral intervention.
  • In the MERS outbreak, for example, most touchable surfaces in MERS units were contaminated by patients and healthcare workers, and viable MERS-CoV could shed through respiratory secretion from patients who were fully recovered clinically.[12]
  • Viral MERS-CoV RNA was detected ≤ 5 days from environmental surfaces after the last positive PCR from patients' respiratory specimens.
  • As appears to be the case for SARS-CoV-2, strict environmental surface hygiene practices should be followed, and the isolation period should be based on laboratory findings rather than on clinical symptoms alone.
  • Current CDC recommendations for preventing environmental and community transmission of SARS-CoV-2 include[13]:
    - Practicing good hygiene: Stop handshaking; clean hands frequently; avoid touching faces with unwashed hands; cover coughs and sneezes.
    - Environmental measures: Perform thorough cleaning; disinfect surfaces such as doorknobs, tables, desks, and handrails regularly; increase ventilation by opening windows or adjusting air conditioning.
    - Limit meetings and travel: Use videoconferencing for meetings when possible or hold meetings in open, well-ventilated spaces; consider adjusting or postponing large meetings or gatherings; assess the risks for business travel.
    - Safe food handling: Limit food sharing; improve health screening; and ensure strict hygiene practices for food service staff and their close contacts.
    - Self-isolation: Stay home if ill or if a family member in the home is ill.
    - As there are no specific therapies or vaccines for SARS-CoV-2, early containment and prevention of further spread are essential to stop the ongoing outbreak.

Clinical Implications

  • COVID-19 transmission routes may include environmental contamination by fecal shedding, and virus droplets on surfaces may remain viable for up to 9 hours.
  • Similarities of SARS-CoV-2 to other human respiratory coronaviruses may help identify environmental containment strategies and even therapeutic targets.
  • Implications for the Healthcare Team: As there are no specific therapies or vaccines for SARS-CoV-2, early containment and prevention of further spread are essential to stop the ongoing outbreak. Advising against frequent face touching can prevent self-inoculation. All HCPs and the public should continue to practice appropriate hand hygiene and infection prevention strategies as outlined by the CDC and WHO.

 

Earn Credit