The New Coronavirus – What We Know and Don’t Know

We don’t know how widely the new coronavirus is spreading undetected in the United States, which makes it more important for residential cleaning service owners to map out worst-case scenarios. There are no clear or defined thresholds to trigger responses such as school closings and cancellations of public events, but these will lead to questions from your clients, if they haven’t asked already, as to what you are doing to protect them from the new coronavirus while you are in their home.

Schools are already closed in Alabama, Arkansas, Kentucky, Ohio, Texas, and elsewhere, but this is due to this year’s virulent flu season, not the new coronavirus (1). At present, the flu is infecting and killing more people than the new coronavirus, but based on current information, the coronavirus seems to have a relatively higher mortality rate. The risk is even higher for people aged 60 and older who have other medical conditions, such as diabetes or COPD. China hasn’t reported any deaths from the virus among children nine years and younger. Regardless, the last thing we want is two deadly viruses circulating at the same time. The flu and coronavirus should motivate people to guard their health and the health of others by covering coughs, washing hands thoroughly, and disinfecting frequently touched objects.

This new virus is called severe acute respiratory syndrome coronavirus 2, or SARS-CoV-2. The disease it causes is called COVID-19. The virus infects the lower respiratory tract. Patients initially develop a fever, cough, and aches, which can progress to shortness of breath and complications from pneumonia. They might develop nausea, with vomiting and diarrhea. Some become only mildly ill or are infected and don’t get sick at all. Others are mildly ill for a few days, then rapidly develop more severe symptoms of pneumonia.

The virus is transmitted through respiratory droplets when an infected person speaks, coughs, or sneezes, according to the World Health Organization. The droplets spread through the air and can land on another person’s mouth and nose, or possibly be inhaled into their lungs, infecting them. The droplets can also land on nearby surfaces, where they can survive for up to nine days, depending on conditions such as type of surface, temperature, and humidity (2). A person can become infected by touching a contaminated surface, then touching their mouth, nose or eyes. Scientists are also investigating whether the new coronavirus might spread through urine or feces, since tests have found it in the digestive tract of some patients, but is generally thought exposure this way is low (3).

There is no specific treatment or vaccine for the virus. Those who have it should seek supportive care to help manage symptoms – which is the same way seasonal influenza is managed. The difference is that those with coronavirus will have to go through a longer isolation.

People become ill between two and 14 days after infection, according to most estimates. Chinese researchers recently cited an average incubation period of 5.2 days. It is not known whether people who get sick are immune from reinfection (4).

Health experts and mask makers say only a properly used and reusable N95 respirator mask can guard against the virus. Paper or polyurethane foam masks don’t filter out the smaller particles responsible for transmitting infectious agents. They might, however, prevent sick people from transmitting to others. The CDC currently is discouraging the use of masks for the general population.

The most important thing you can do to protect yourself is wash your hands frequently using a prescribed method that removes soil from all parts of your hand, for at least 40 seconds each time (5). Wash them regularly when you are working, when you come home, before you eat, and other times you are touching public surfaces. You can also use an alcohol-based hand sanitizer. Don’t touch your eyes, nose or mouth. Maintain a distance of at least 6 feet from people who are sick.

Role of Cleaning Professionals in Cleaning for Health

Cleaning professionals play a key role in maintaining the health of homes and their inhabitants. Removing contaminants from the indoor environment reduces human exposure to disease and the risk of infection, having health implications for cleaning technicians and their clients.

It is important that the home serve as a primary line of defense against infectious diseases. Good home hygiene provides this defense, preventing most of the infections that can arise in the home. Hygiene refers to practices associated with ensuring good health, cleanliness, and sanitation. In relation to infectious diseases, the term hygiene, applied to the home, is usually used to refer to the various procedures which are used to prevent spread of infectious diseases – handwashing, food hygiene, laundry, safe disposal of human and other waste, care of pets, care of the sick, and control of dust-borne allergens. Control of infectious diseases is high on the national health agenda, prompting new emphasis on developing strategies for prevention and control. This is being driven by the growing immune-compromised population living in the community and the seemingly constant emergence of new pathogens, including antibiotic resistant strains. In response to the threat from emerging pandemic strains such as SARS-CoV-2, hygiene is now seen as an important first line of defense.

Life, and germs, happen. And because we live life, which keeps us on the go and exposed to many people and outside environments, germs are constantly introduced into the home. This can happen through people who have an infection or may be asymptomatic carriers of germs, contaminated food, domestic animals, by air, and sometimes by water. Within the home, there is a series of events, called the Chain of Infection (see Figure 1), which results in the spread of germs to family members in the home. Breaking the “spread of germs” link is a principle way to prevent the spread of infection and is achieved by good cleaning and hygiene practices. In developing good cleaning and hygiene practices, the International Scientific Forum on Home Hygiene (IFH) (6) used a risk-based approach to identify major routes for the spread of germs. This shows that the “critical control points,” or the places where hygiene is most important, for breaking the chain of infection are the hands, together with hand contact surfaces, cleaning cloths and other cleaning utensils. By keeping these surfaces and items clean we can significantly reduce the spread of infections. This approach to home hygiene is called “targeted hygiene” by the IFH.

Figure 1:

There are five links in the chain of infection. All these links must be in place for an infection to pass from a source to a person and for the infection to take hold.

  • Source of germs –Someone, or something, like pets, or contaminated food or water, carries the germs that cause illness into the home. Some bacteria, viruses and fungi such as molds can also be present on dust or in the air.
  • Method of exit – How do germs leave an infected person or contaminated source? Droplets from the mouth and nose, feces, vomit, skin scales, hairs and wound fluid can contaminate hands, surfaces, fabrics, food and air.
  • Method of spread –Germs spread by passing to other people. They can be carried on contaminated hands by people touching other people, surfaces, and food. They can also transfer via interaction between an infected and a healthy person by kissing, touching or sharing a bed. People can encounter soiled equipment, surfaces, cleaning cloths, linen and dressings as well as touching contaminated food. Some microbes such as fungal spores, viruses, or bacteria attach to dust and are carried through the air, or carried in aerosolized droplets produced by coughing, sneezing or vomiting.
  • Method of entry – Germs can be breathed in, swallowed, enter through a break in the skin (cuts and wounds), or enter through mucous membranes, including the surface of the eye. They can also enter the human body via medical intravenous lines and catheters.
  • Susceptible person – We are all at risk of infection. Some people are at extra risk, such as those with lowered defenses to infection due to their age or illness. Susceptibility to infection is increased by certain factors: extremes of age; no previous exposure to a particular germ or no immunizations to build up immunity; invasive devices for medical needs such as feeding tubes, catheters or IVs; and drug treatments like chemotherapy or diseases that affect the immune system.

Most microbes in the home are not harmful, but pathogenic germs are always present somewhere. Infection can be passed directly from person to person or indirectly through contact with contaminated surfaces, equipment or unwashed hands. Breaking the chain of infection by removing one or more links can prevent the infection from taking hold. Now that we’ve looked at the links in the infection chain, let’s look at the weaknesses of each link.

  • Sources of germs – Keeping infected people away from others will isolate the germs. In the kitchen, take care when handling raw foods and clean these surfaces well. Elsewhere in the house, handle items like soiled diapers and soiled tissues with care.
  • Method of exit – Preventing feces, vomit, fluids from wounds, coughs or sneezes from getting onto surfaces or hands is important for keeping germs contained. “Catch” your germs by coughing or sneezing into the crook of your elbow or a disposable tissue.
  • Method of spread – Using the targeted hygiene approach of cleaning frequently touched surfaces to prevent germs from spreading to other people or things that are shared is an important way to break the chain of infection. Cleaning and maintenance of cleaning equipment is also important.
  • Method of entry – Washing hands frequently and avoiding touching your mouth, nose and eyes will inhibit the spread of germs.
  • Susceptible person – Protect everyone by keeping up to date with appropriate immunizations and teaching proper handwashing techniques.

Targeted Hygienic Cleaning

In his book Protecting the Built Environment: Cleaning for Health, Dr. Michael Berry defines hygienic cleaning as cleaning for health first and appearance second. Dr. Berry calls cleaning, “the science of controlling contaminants.” The goal of cleaning, he explains, should be to remove or reduce the level of harmful substances that can threaten human health.

The International Scientific Forum on Home Hygiene (IFH) states that hygienic cleaning means reducing the number of germs on a surface to a “safe level,” one that is not harmful to human health. The IFH has developed guidelines for prevention of infection and cross contamination in the domestic environment. Their risk-based approach is known as “targeted hygiene.”

Since the infectious dose for many common germs, especially common viruses, can be very small, to break the chain of infection, a “hygienic cleaning” procedure should be used which eliminates as many germs as possible from critical surfaces. Hygienic cleaning can be done in one of three ways: either by detergent-based cleaning with rinsing; by using an EPA registered disinfectant which kills the germs on surfaces; or by killing the germs with steam vapor above 212 degrees Fahrenheit. In many situations, like handwashing, a hygienically clean surface can be achieved by soap and water alone. Soaps and detergent products are an important part of good hygiene in the home. Their main function is to help lift dirt from hands and surfaces when we rub or scrub them, so the dirt can be more easily wiped or rinsed away, but studies suggest that this is only effective if accompanied by thorough rinsing and/or drying.

Cleaning to remove soil and germs from surfaces is a recognized component of hygiene. The absence of soil and moisture deprives germs of their ideal breeding ground, so keeping home surfaces free of these soils and moisture can help reduce the spread of germs like SARS-CoV-2. But removal of visible dirt does not guarantee the reduction of microbes to a safe level for human health. As noted previously, wiping a surface can remove all visible dirt but still leave behind quite a few germs. To ensure that surfaces are germ free, after cleaning with soap or detergent they need to be thoroughly dried. For high-touch surfaces a disinfectant may be required if a pathogen like SARS-CoV-2 is a concern. A disinfectant is a product that kills or inactivates microbes on hands or hard surfaces. Disinfection can be achieved by heating a surface to a specified temperature for a specified time (as with steam vapor) or by using a chemical disinfectant.

Ever since SARS-CoV-2 appeared in China, Professional Cleaners have been concerned about finding an effective cleaning solution to eliminate it. The SARS-CoV-2 is an enveloped virus, and typically, these viruses are not terribly difficult to kill on surfaces. When a new virus appears, there is a tendency to go for the strongest disinfectant conceivable to disinfect a surface. With a harder to kill virus, or a virus with a particularly high mortality rate, that may be appropriate. However, for SARS-CoV-2 that appears to be unwarranted. The CDC states that no additional disinfection beyond routine cleaning is recommended at this time (7). The World Health Organization (WHO) recommends that, “If you think a surface may be infected, clean it with simple disinfectant to kill the virus and protect yourself and others (3).” In the normal course of events, where surface contamination is a concern but not a confirmed risk, then using a generally available, hospital-grade disinfectant should be enough to ensure a clean and disinfected surface. Many household disinfectants are hospital-grade and will be designated as such on the label. Keep in mind that unnecessarily strong disinfectants, such as highly concentrated chlorine solutions (household bleach, or sodium hypochlorite, to name one), or those with a very high or very low pH, can degrade or destroy some surfaces and cause health problems for those exposed to the disinfectant.

As reported in the Journal of Hospital Infection (2), researchers found using a solution that is 62% to 72% ethanol (alcohol), 0.5% hydrogen peroxide, or 0.1% sodium hypochlorite (chlorine bleach) will kill the SARS-CoV-2 virus within one minute of exposure time. In contrast, the scientists found that solutions containing 0.04% benzalkonium chloride, 0.06% sodium hypochlorite, and 0.55% ortho-phtalaldehyde were less effective at killing the new virus. Notice when using alcohol or chlorine bleach as a disinfectant for the SARS-CoV-2 virus solution concentrations matter.

The American Chemistry Council’s (ACC) Center for Biocide Chemistries (CBC) has compiled a list of products that have been pre-approved by the EPA for use against emerging enveloped viral pathogens that can be used during the 2019 novel coronavirus (COVID-19) outbreak (8).

Of course, using the proper disinfectant is only one part of the equation. Cleaning and disinfection procedures must be followed consistently and correctly to be effective, as disinfectants cannot do their job killing germs if there is soil on the surface you want to disinfect. This means reading the label first, then cleaning the hard surface thoroughly with soap or detergent to remove all visible and invisible soil. Apply the disinfectant solution to the cleaned surface and keep the surface wet for the full dwell time recommended on the label. This could be as long as 10 minutes. The next step is to remove the remaining disinfectant with a clean, dry cloth with linear, overlapping strokes – no circular motions or scrubbing – if the instructions do not recommend air drying (9).

Correct use of disinfecting wipes depends on whether you’re aiming to sanitize or disinfect the surface. Sanitizing a surface reduces, but not necessarily eliminates, germs from surfaces to levels considered safe as recognized by public health standards or regulations. Disinfection takes this to an even higher level by destroying or irreversibly inactivating germs, but not necessarily their spores.

Disinfecting wipes are suitable for most surfaces because most are bleach-free. To correctly disinfect a countertop, for example, the surface needs to be visibly wet for four minutes. That means you must use a fresh wipe to re-wet the surface every time the surface begins to dry before the four-minute dwell time is over, which is probably more than is reasonable or cost-effective to use. Let the surface air dry. This information is included on the container label, though many people breeze past this to get straight to cleaning (11). As with all cleaning products, you should read all label instructions carefully.

Consider using high-quality, hospital-grade microfiber cloths in place of cotton cloths to clean surfaces. Spraying and wiping a surface with a detergent and a cotton cloth will often merely move organisms around the surface and onto the cleaning cloth and hands of the person cleaning, just to be transferred to other surfaces. Made from synthetic materials, typically a polyester-nylon blend, microfiber is a very fine, highly absorbent material which makes it much more effective than cotton at picking up and removing soil and germs from surfaces, reducing the incidence of cross-contamination (12).

For hygienic cleaning, it is also critical to designate different color cloths for different rooms. For example, orange for bathrooms, green for kitchens and blue for all other rooms. This will prevent cross contamination and the spreading of germs.

Standard Precautions for Cleaning

People who work in the health care field are familiar with Standard Precautions (8), a group of infection-prevention practices that apply to all patients and health care workers. These precautions are designed to protect caregivers from catching infections from the patient and protect the patients from infection transmission via the caregiver. Standard Precautions are based on the principle that all blood, body fluids, secretions, excretions, non-intact skin and mucous membranes may contain transmissible infectious agents. Standard Precautions include the use of gloves, gowns, masks, eye protection or face shields, as well as safe handling of equipment or items that are likely to have been exposed to infectious fluids in the patient environment. All these precautions are designed to stop the transmission of infection.

Cleaning Professionals should take a lesson from Standard Precaution practices and treat every bathroom as if there are pathogenic germs present. Gloves (nitrile, not latex) should be required when cleaning bathrooms and kitchens, as should glasses or goggles. In such situations, where there is a known risk, hygienic cleaning should be applied to prevent the spread of germs. A hygienically clean surface can be achieved by using either a detergent or disinfectant. In some cases, a combination of these two is best.

High Touch Surfaces

High touch surfaces should be the focus of special attention when cleaning. Germs can survive for several hours to many days on surfaces, depending on the specific germ. When hands touch a surface, they can pick up these germs and spread them to other surfaces and people. High touch surfaces that need frequent cleaning, and disinfecting when practical, include:

  • Toilet handles, seats and lids
  • Handles of cupboards, microwaves, ovens and refrigerators
  • Surfaces contaminated by used diapers, menstrual pads, vomit, feces, blood or other bodily fluids
  • Surfaces and cutting boards used for handling raw meat
  • Telephones, computer keyboards, computer mice, electronics
  • Doorknobs, light switches (and areas around these items that tend to get grimy), handrails

Equipment Hygiene

Equipment hygiene is important. If not cleaned correctly, cleaning cloths, sponges, brushes, mops and cleaning equipment are considered to be reservoir disseminators, or germ spreaders. They pose a high risk of cross-contamination for several reasons:

  • They are used to clean items and surfaces that are soiled with dirt and organic matter. They inevitably become contaminated with microbes and act as reservoirs for germs.
  • They are touched by hands, which in turn, become contaminated.
  • If not thoroughly cleaned, it is likely that some microbes will survive and multiply to high numbers over a period of hours.
  • They can contribute to the spread of microbes if not adequately decontaminated between uses or discarded.

To minimize the risk of cross contamination, cleaning cloths and cleaning equipment must be always hygienically cleaned. Microbes tend to stick to fibers of cleaning cloths, brushes, and mops and may not be removed unless properly cleaned. The best way to make sure these cleaning cloths and mop heads are hygienically cleaned is by washing them in a washing machine. This not only dislodges dirt and microbes but also kills the microbes in the hot water. If a cloth or mop is left wet for several hours, bacteria will multiply and become even more strongly bound. Therefore, it is important to decontaminate cloths and mops and dry them as soon as possible after use (9).

Reusable cloths and removable mop heads should be hygienically cleaned after each use. Cloths can be hygienically cleaned by washing in a washing machine with laundry detergent and water temperature set to at least 160 degrees Fahrenheit.

Clean all brushes, including vacuum attachments, using detergent and warm water between each use. Rinse with hot water and leave with brush heads up to dry.

Clean non-detachable mops using detergent and clean, warm water, then rinse with a disinfecting solution like bleach. Wring out the mop until it is as dry as possible, then leave it heads up to dry.

Buckets should be cleaned in detergent and warm water and rinsed with disinfecting solution like bleach. Finally, they should be rinsed with fresh water. Leave the bucket upside down to dry.

Always wear protective gloves and glasses or goggles when cleaning toilets and children’s potties. Also, learn how to properly remove gloves (13) and glasses or goggles after you are finished cleaning to prevent cross-contamination and to protect yourself from infection. Make sure to wash your hands after removing your gloves. You should also always wear gloves in a client’s home when handling soiled laundry, transferring it from the washer to the dryer, and folding it. Finally, always wear gloves when removing trash.


Microbes are everywhere. A certain percentage of them are pathogenic and can cause illness in humans. It is important to remove pathogenic microbes from the residential environment in order to keep cleaning professionals and their clients safe from infection. Cleaning removes soil, but more is needed to stay healthy. Hygienic cleaning targets and removes pathogenic germs. As stated earlier, as house cleaning professionals we are on the first line of defense against harmful deceases like the new coronavirus. Targeted hygiene and hand washing are two ways Cleaning Professionals can protect themselves and their clients from the spread of infection.