The CDC says that studies suggest that the risk of SARS-CoV-2 infection via the fomite transmission route is low , and generally less than 1 in 10,000 .
disinfection efforts need to be used in combination with other CDC-recommended initiatives , including social distancing , mask wearing , handwashing , staying home when sick , and improving indoor ventilation . The idea of Dr . James Reason ’ s 1990 ‘ Swiss Cheese Model ’ still holds true today . The safeguards recommended represent the multiple layers needed to protect consumers and employees , alike . As pointed out by the Cleveland Clinic , “ when used together consistently , the holes ( or weaknesses ) in any single layer of protection should be offset by the strengths of another layer of intervention .” We must address every area of potential spread to truly create a safe and healthy environment for all .”
One of the most-cited commentaries in The Lancet that excoriated COVID-19 related hygiene theater argued that the risk of SARS-CoV-2 transmission by fomites “ has been assumed on the basis of studies that have little resemblance to real-life scenarios .”
As Goldman ( 2020 ) asserts , “ The longest survival ( six days ) of SARS-CoV on surfaces was done by placing a very large initial virus titer sample ( 10 6 infectious virus particles ) on the surface being tested . Another study that claimed survival of four days used a similarly large sample ( 10 6 infectious virus particles ) on the surface . A report found survival of both SARS-CoV and SARS-CoV-2 of up to two days ( on surfaces ) and three days ( in aerosols generated in the laboratory ), but again with a large inoculum ( 10 5 to 10 7 infectious virus particles per mL in aerosols , 10 4 infectious virus particles on surfaces ). Yet another study found long survival ( five days ) of human coronavirus 229E on surfaces with what I would still consider a substantially large viral load ( 10 ³ plaque-forming units ) in a cell lysate . However , using a cell lysate rather than purified or semi-purified virus might enable initial viral proliferation or protection from the effects of the sample drying out . None of these studies presents scenarios akin to real-life situations . Although I did not find measurements of coronavirus quantities in aerosol droplets from patients , the amount of influenza virus RNA in aerosols has been measured , with a concentration equivalent to 10-100 viral particles in a droplet , with even fewer infectious influenza virus particles capable of growth in a plaque assay . By contrast , one study found human coronavirus 229E to survive for only three to six hours ( depending on the surface tested ), and human coronavirus OC43 to survive for one hour , after drying on various surfaces including aluminum , sterile latex surgical gloves , and sterile sponges . In a study in which the authors tried to mimic actual conditions in which a surface might be contaminated by a patient , no viable SARS-CoV was detected on surfaces . A 2020 literature review included most of the studies I have cited here ( and others ), but adds no new research , and in my view , does not critically evaluate previously published studies .”
Goldman ( 2020 ) did not dispute the findings of these studies , only the applicability to real life , and adds , “ For example , in the studies that used a sample of 10 7 , 10 6 , and 10 4 particles of infectious virus on a small surface area , these concentrations are a lot higher than those in droplets in real-life situations , with the amount of virus actually deposited on surfaces likely to be several orders of magnitude smaller . Hence , a real-life situation is better represented in the work of Dowell and colleagues ( 2004 ) in which no viable virus was found on fomites .”
The take-away message , Goldman ( 2020 ) emphasizes , is “… the chance of transmission through inanimate surfaces is very small , and only in instances where an infected person coughs or sneezes on the surface , and someone else touches that surface soon after the cough or sneeze ( within one to two hours ). I do not disagree with erring on the side of caution , but this can go to extremes not justified by the data . Although periodically disinfecting surfaces and use of gloves are reasonable precautions especially in hospitals , I believe that fomites that have not been in contact with an infected carrier for many hours do not pose a measurable risk of transmission in non-hospital settings . A more balanced perspective is needed to curb excesses that become counterproductive .”
When asked about his Lancet commentary , Emanuel Goldman , professor of microbiology at Rutgers NJ Medical School , says , “ Early in the COVID-19 pandemic , there was incorrect information disseminated by public health authorities based on results of unrealistic experiments showing long times of virus survival on surfaces . Even though the CDC has finally recognized this mistake and changed its advice , earlier incorrect perceptions remain in the public consciousness , leading to continued ‘ hygiene theater ’ and absurd excessive cleaning and disinfection . Although resistance issues in bacteria may be exacerbated by this behavior , in my view the greater danger is the risk of poisoning by these harsh disinfecting treatments . For example , during the pandemic , there has been a sharp increase in calls to poison control centers . Sadly , healthcare facilities also often remain behind the current state of knowledge and continue excessive and unnecessary disinfection . Hospitals must maintain a clean environment . This was true before the pandemic and remains true today . Hospitals should continue the cleaning protocols that were in place before the pandemic . They do not need to augment these protocols , as the prior procedures that were employed are more than adequate to manage any potential risk for COVID-19 .”
Since the Goldman ( 2020 ) commentary was published , the avalanche of studies released either in pre-print versions as well as peer-reviewed papers has continued , and experts started embracing a new paradigm – most recently evidenced in the CDC ’ s shift on April 5 , 2021 to state that , “ The principal mode by which people are infected with SARS-CoV-2 ( the virus that causes COVID-19 ) is through exposure to respiratory droplets carrying infectious virus . It is possible for people to be infected through contact with contaminated surfaces or objects ( fomites ), but the risk is generally considered to be low .” ( CDC , 2021 )
As the CDC ( 2021 ) explains , the risk of fomite-mediated transmission is dependent on :
●The infection prevalence rate in the community ●The amount of virus infected people expel ( which can be substantially reduced by wearing masks ) ●The deposition of expelled virus particles onto surfaces
( fomites ), which is affected by air flow and ventilation
●The interaction with environmental factors ( e . g ., heat and evaporation ) causing damage to virus particles while airborne and on fomites
●The time between when a surface becomes contaminated and when a person touches the surface