Quotes from Experts

Cleaning and hygiene during the COVID-19 outbreak

SciLine reaches out to our network of scientific experts and poses commonly asked questions about newsworthy topics. Reporters can use these responses in news stories, with attribution to the expert.

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What are Quotes from Experts?

March 1, 2021


How important is it to regularly disinfect surfaces, given our current understanding of COVID-19 transmission?


“Keeping household surfaces clean has a variety of benefits for your health, but preventing the spread of COVID-19 is actually done best by other methods, especially avoiding close contact with people from outside our own household (especially if they are symptomatic), covering our faces when in public, and giving others plenty of personal space, at least 6 feet. This is because we now understand that most COVID-19 is transmitted by respiratory droplets exhaled by one person and breathed in by another. Although those droplets can live for a short time on a surface making them a possible threat to someone who would touch them and then pick their nose, this turns out to be a relatively less important mode of transmission.” (Posted March 1, 2021)

Paul Pottinger, MD
Professor of Medicine, Division of Allergy & Infectious Diseases, University of Washington School of Medicine

“Not important. With rare possible exceptions, this is a virus you catch by breathing, not by touching. Routine hygiene and cleanliness are all that’s needed.” (Posted March 1, 2021)

Emanuel Goldman, PhD
Professor of Microbiology, Rutgers-New Jersey Medical School

“SARS CoV-2, the virus that causes COVID-19, is most commonly transmitted by direct respiratory exposure to large aerosol droplets that are released by an infected individual.  Virus-laden particles can fall to surfaces which can serve as an indirect source of infection to an individual who touches that surface and subsequently touches their nose, mouth, and/or eyes (also called fomite transmission).  This is now recognized as a less likely way to get infected than the respiratory route. That being said, it remains important to regularly disinfect so-called “high touch” surfaces, or those that are frequently contacted by many different people, like doorknobs and handles in public places. It is also prudent to regularly disinfect surfaces that have a higher likelihood of contact with an infected person, such as countertops or cash registers in restaurants or stores.”  (Posted March 1, 2021)

Lee-Ann Jaykus, PhD
Professor, Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University

Does the SARS-CoV-2 virus survive longer on certain types of surfaces?


“Yes. Surfaces that are relatively smooth and also shaded from ultraviolet light and not exposed to harsh temperatures tend to be a more happy home for the virus, although even under ideal circumstances it does not seem to live for more than a matter of hours or perhaps days there. The virus that causes COVID-19 is harder to catch from cloth surfaces, rough surfaces, or surfaces that are exposed to ultraviolet light or very high or low temperatures.” (Posted March 1, 2021)

Paul Pottinger, MD
Professor of Medicine, Division of Allergy & Infectious Diseases, University of Washington School of Medicine

“Yes, there are some differences in virus half-lives depending on the surface. But with a realistic amount of virus that could likely contaminate a surface, the virus will be dead in less than a day regardless of the surface.” (Posted March 1, 2021)*

Emanuel Goldman, PhD
Professor of Microbiology, Rutgers-New Jersey Medical School

“Recent laboratory-based studies suggest that SARS CoV-2 can remain on surfaces for prolonged periods of time, perhaps 2-4 weeks.  This is dependent upon the surface as well as temperature and the presence of organic matter (soil or filth); lower temperatures and filth are more protective of the virus.  Nonetheless, it is extremely important to understand the dynamics of virus survival on surfaces, as the virus gradually loses its ability to infect, the more time it spends on a surface. Overall, about 99% of the infectious virus on common surfaces (e.g., stainless steel, glass, vinyl) is lost within 5-7 days at room temperature.” (Posted March 1, 2021)

Lee-Ann Jaykus, PhD
Professor, Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University

* Links included in quotes were supplied by the expert.


Is regular hand washing or hand sanitizer use still important for preventing the spread of COVID?


“Keeping our hands clean using either soap and water or an alcohol-based hand rub is always a good idea, not only to reduce the chance of catching COVID-19 but also to reduce the chance of diarrheal illnesses, which are actually easier to catch in this manner.” (Posted March 1, 2021)

Paul Pottinger, MD
Professor of Medicine, Division of Allergy & Infectious Diseases, University of Washington School of Medicine

“These are reasonable precautionary measures, which would be the case even if there were no pandemic.” (Posted March 1, 2021)

Emanuel Goldman, PhD
Professor of Microbiology, Rutgers-New Jersey Medical School

“Yes, extremely important.  We, oftentimes unaware, touch our faces many, many times during the day. If SARS CoV-2 is on our hands, the simple action of touching the face increases the opportunity to deposit virus in the eyes, nose and/or mouth, which contain the tissues that the virus infects. Handwashing and use of alcohol-based hand sanitizers are well recognized as effective ways to remove/inactivate SARS CoV-2. Hand washing and sanitizing should continue to be done routinely and frequently, and always after having had hand contact with high touch surfaces or after being in locations for which you do not have control of surface sanitation, like stores, eating establishments, places of work.” (Posted March 1, 2021)

Lee-Ann Jaykus, PhD
Professor, Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University

March 23, 2020


How helpful for avoiding COVID-19 is it to clean home surfaces and cell phones?


“We are still learning about this new coronavirus, but it is likely that one way it spreads is through contaminated surfaces. Frequently cleaning surfaces should help.” (Posted March 23, 2020)

Daniel M. Parker, PhD
Assistant Professor in the Department of Epidemiology at the University of California, Irvine

“If you live with other people or individuals come to your home, it would be a good idea to disinfect common surfaces like kitchens, bathrooms, laundry areas, computers and phones. The rule of thumb is that if someone used an area and you are going to use that area, clean it off. If you don’t have cleaning products, wash your hands carefully after use of any common surfaces and areas.” (Posted March 23, 2020)

Carl J. Fichtenbaum, MD
Professor of Clinical Medicine at the University of Cincinnati College of Medicine

“One important point to remember here is that cursory cleaning and decontamination can inadvertently spread localized contamination over a wider area. It should also be noted that there are only a few studies documenting the relative importance of high-touch environmental surface decontamination in infection prevention and control, even though it makes sense logically.” (Posted March 23, 2020)

Syed A. Sattar, MSc, Dip Bact, MS, PhD, RM (CCM), FAAM, FRSPH
Emeritus Professor of Microbiology, Faculty of Medicine, Univ. of Ottawa, Ottawa, Ontario, Canada

“By far, the most important surface to clean is the surface of your hands! Hand hygiene is the biggest, simplest, cheapest step you can take to protect yourself from coronavirus, and most any respiratory viral illness! But it only works if you do it, properly and consistently, before eating or touching your face, or after touching high-touch public surfaces such as doorknobs. As for the phone—yes, that is the highest-yield surface in the house to keep clean, because we touch our phones so often. The rest of the house is a much lower priority to clean, so long as we are careful to clean our hands when we come home!” (Posted March 23, 2020)

Paul Pottinger, MD
Professor of Medicine, Division of Allergy & Infectious Diseases, University of Washington School of Medicine

“We need to be more aggressive than usual in cleaning home surfaces and cell phones. According to studies recently, the virus can live on various surfaces for several days.” (Posted March 23, 2020)

Jagdish Khubchandani, MBBS, PhD, MPH
Professor of Health Science, Ball State University, Indiana

What cleaning product ingredients work best against the virus?


“Soap and water, bleach solutions, and alcohol solutions work well. There are likely others, but these are ingredients that should be relatively easy to find and use. Make sure to follow CDC or WHO guidelines on concentrations for alcohol- and bleach-based solutions.” (Posted March 23, 2020)

Daniel M. Parker, PhD
Assistant Professor in the Department of Epidemiology at the University of California, Irvine

“Any disinfectants (quaternary ammonium-based compounds, sodium hypochlorite, isopropanolamine, ethanol-based compounds, ammonium hydroxide, etc.) and diluted household bleach (1:10 dilution).” (Posted March 23, 2020)

Carl J. Fichtenbaum, MD
Professor of Clinical Medicine at the University of Cincinnati College of Medicine

“Being an enveloped virus, it can be killed even with mild detergents such as plain soap. Published studies have also confirmed its susceptibility to all major classes of disinfectants.” (Posted March 23, 2020)

Syed A. Sattar, MSc, Dip Bact, MS, PhD, RM (CCM), FAAM, FRSPH
Emeritus Professor of Microbiology, Faculty of Medicine, Univ. of Ottawa, Ottawa, Ontario, Canada

“SARS-CoV-2 is not difficult to inactivate: most any standard household disinfectant will do. The EPA provides a list of products that are safe and effective for this purpose.” (Posted March 23, 2020)

Paul Pottinger, MD
Professor of Medicine, Division of Allergy & Infectious Diseases, University of Washington School of Medicine

“Routine household disinfectants may not help control coronavirus. If preventing coronavirus is the goal, individuals should look for ingredients with antiviral effects like hydrogen peroxide, isopropyl alcohol, ethanol, or bleach (sodium hypochlorite) rather than those with antibiotic properties.” (Posted March 23, 2020)

Jagdish Khubchandani, MBBS, PhD, MPH
Professor of Health Science, Ball State University, Indiana

If traditional cleaning products are sold out, are there recipes using household products that will also kill the virus?


“As with your hands, you can also quite effectively use soap and water to clean surfaces in your house.” (Posted March 23, 2020)

Daniel M. Parker, PhD
Assistant Professor in the Department of Epidemiology at the University of California, Irvine

“In my view, the best option here is to use soap and water.” (Posted March 23, 2020)

Syed A. Sattar, MSc, Dip Bact, MS, PhD, RM (CCM), FAAM, FRSPH
Emeritus Professor of Microbiology, Faculty of Medicine, Univ. of Ottawa, Ottawa, Ontario, Canada

“Options for sanitizing hard surfaces include 70% alcohol solution, dilute bleach (1/4 cup per gallon of water), and 0.5% hydrogen peroxide. Be warned, these solutions will inactivate coronavirus, but may also damage the surface you are trying to clean. If in doubt, test a small area first.” (Posted March 23, 2020)

Paul Pottinger, MD
Professor of Medicine, Division of Allergy & Infectious Diseases, University of Washington School of Medicine

How should people clean their hands to avoid viral transmission?


“Coronaviruses are not particularly tough. Soap and water, used properly, will dislodge the virus from your hands and can destroy their outer surface area. Wet your hands under running water (can be warm or cold), apply soap, lather your hands well and scrub all over, then rinse your hands under running water for at least 20 seconds.

“Alcohol based hand sanitizers should also kill the new coronavirus. However, make sure your hand sanitizer actually has at least 60% alcohol (many do not). Hand sanitizer really should be secondary to washing your hands with soap. In some situations (when you’re in public) it isn’t possible to wash your hands, and sanitizer can then be helpful. Most of us should now be staying home and should have access to soap and water. Also, try to not touch your face. This can be difficult but with practice you can reduce the frequency and duration of face touching.” (Posted March 23, 2020)

Daniel M. Parker, PhD
Assistant Professor in the Department of Epidemiology at the University of California, Irvine

“Wash hands with soap and water for 30 seconds (sing Happy Birthday song twice to guide time); make sure to rub soap between fingers and under nails. Hand sanitizer can be used as well for the same amount of time.” (Posted March 23, 2020)

Carl J. Fichtenbaum, MD
Professor of Clinical Medicine at the University of Cincinnati College of Medicine

“Handwashing with plain soap and water remains the best and the safest means of decontaminating hands. However, the following must be kept in mind: Proper handwashing constitutes (1) prewetting of hands with water, (2) application of soap (liquid, bar or foam) followed by lathering for about 20 seconds; the soap need not contain any added anti-microbial ingredients, (3) thorough rinsing of the lathered hands with water, and (4) drying of the rinsed hand with a paper towel, cloth towel or a warm-air hand dryer. Immediate recontamination of the washed hands must be avoided by turning off the tap with one’s elbows, for example.” (Posted March 23, 2020)

Syed A. Sattar, MSc, Dip Bact, MS, PhD, RM (CCM), FAAM, FRSPH
Emeritus Professor of Microbiology, Faculty of Medicine, Univ. of Ottawa, Ottawa, Ontario, Canada

“Washing hands carefully with soap and water (see handwashing recommendations about 20 seconds of scrubbing, making sure you clean between fingers, back of hands and thumbs) is always preferable to alcohol-based sanitizers for any virus. The physical action of rubbing, the surfactant action of the soap, and the running water help remove the viruses from hands.

“Alcohol-based sanitizers are useful when soap and running water are not available or out of convenience when you need to clean your hands quickly. Alcohol-based hand wipes can also help remove viruses from hands but need to be used carefully to cover all the hand/finger surfaces.” (Posted March 23, 2020)

Christine L. Moe, PhD
Professor of Safe Water and Sanitation at Emory University

“This makes such a difference! Please do keep your hands clean—really clean—either by washing with plain soap and water for 20 seconds or by diligently applying an alcohol-based hand rub for at least 20 seconds. Either way, make sure you clean your whole hands… including the thumbs!” (Posted March 23, 2020)

Paul Pottinger, MD
Professor of Medicine, Division of Allergy & Infectious Diseases, University of Washington School of Medicine

“First, soap and water are preferred over hand sanitizers. Second, a minimum of 20 seconds of hand washing. Third, all areas of the hands should be scrubbed- front, back, between fingers.” (Posted March 23, 2020)

Jagdish Khubchandani, MBBS, PhD, MPH
Professor of Health Science, Ball State University, Indiana

Can alcohol-based or DIY hand sanitizers be used in place of store-bought sanitizers?


“I would not recommend DIY hand sanitizer. It may seem straightforward and simple, but there are many variables that influence whether or not hand sanitizer is effective. You need to have an alcohol concentration that is strong enough come into contact with the virus for a long enough period of time to kill it. If the sanitizer is mostly alcohol, it could evaporate before there has been sufficient time to kill the virus. If the sanitizer doesn’t have a strong enough concentration of alcohol, it also won’t work. If your hands are soiled, it is possible that even a good concentration of alcohol won’t actually reach the pathogens. Again, properly washing your hands with soap will work.” (Posted March 23, 2020)

Daniel M. Parker, PhD
Assistant Professor in the Department of Epidemiology at the University of California, Irvine

“Yes, if the % alcohol is more than 60% it will reliably kill viruses (e.g., 120 proof Everclear).” (Posted March 23, 2020)

Carl J. Fichtenbaum, MD
Professor of Clinical Medicine at the University of Cincinnati College of Medicine

“Yes, one can prepare handrubs at home as long as they contain a minimum of 60% ethanol (isopropyl or rubbing alcohol is generally less effective against viruses) with an emollient such as glycerol. The 2009 guideline from the WHO gives more details in this regard.” (Posted March 23, 2020)*

Syed A. Sattar, MSc, Dip Bact, MS, PhD, RM (CCM), FAAM, FRSPH
Emeritus Professor of Microbiology, Faculty of Medicine, Univ. of Ottawa, Ottawa, Ontario, Canada

* Links included in quotes were supplied by the expert.


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Daniel M. Parker, PhD, Assistant Professor in the Department of Epidemiology at the University of California, Irvine, said:

“I declare that I have no competing interests.”

Carl J. Fichtenbaum, MD, Professor of Clinical Medicine at the University of Cincinnati College of Medicine, said:

None

Syed A. Sattar, MSc, Dip Bact, MS, PhD, RM (CCM), FAAM, FRSPH, Emeritus Professor of Microbiology, Faculty of Medicine, Univ. of Ottawa, Ottawa, Ontario, Canada, said:

“I am Chief Scientific Officer at CREM Co Labs, Mississauga, Ontario, Canada, an R&D facility that also assesses infection prevention and control (IPAC) technologies. I am an advisor to the World Health Organization (WHO) on hand hygiene. In addition, I am on the advisory board of one Canadian company that makes disinfectants and on the board of directors of two NGOs (Healthcare Surfaces Institute and the International Nosocomial Infection Control Consortium).”

Paul Pottinger, MD, Professor of Medicine, Division of Allergy & Infectious Diseases, University of Washington School of Medicine, said:

None

Jagdish Khubchandani, MBBS, PhD, MPH, Professor of Health Science, Ball State University, Indiana, said:

None

Emanuel Goldman, PhD, Professor of Microbiology, Rutgers-New Jersey Medical School, said:

I am an unpaid scientific advisor (recruited by the Rutgers University Corporate Engagement Center) to the Grignard Company. This company produces “Grignard Pure” (GP), an indoor air dispersal product that kills viruses, including SARS-Co-V-2 (the cause of COVID-19).

Lee-Ann Jaykus, PhD, Professor, Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, said:

 My laboratory group at NCSU periodically receives fee-for-service funding from companies that manufacture commercial hand sanitizers and surface disinfectants, to evaluate anti-noroviral efficacy. We do not currently do any work with SARS CoV-2.