This scanning electron microscope image shows SARS-CoV-2 (yellow)—also known as 2019-nCoV, the virus that causes COVID-19—isolated from a patient in the U.S., emerging from the surface of cells (blue/pink) cultured in the lab. Credit: NIAID-RML
The Coronavirus is now front and center of the world stage. But how prepared is your cleaning program? In the days following the news of the Coronavirus in the U.S., I often would hear this one statement "You are three times more likely to catch the flu rather than the Coronavirus." Although in part true, the CDC reports 13 million flu cases thus far in the 2019-20 season and at least 8,200 people have died from it. In lieu of such information, it's essential to understand what makes individuals more apt to contracting influenza rather than Coronavirus. It gives pause to the question "if we aren't effective in mitigating influenza, how are we able to do so with the Coronavirus?"
The Science of Coronavirus
Virology is the study of viruses and virus-like agents. It's vital to understand viruses since they cause infectious diseases. In doing so, scientists can formulate both vaccines and or chemical agents to combat outbreaks. Both the Environmental Protection Agency (EPA) and the Centers for Disease Control and Prevention (CDC) identify that microorganisms can be ranked based on their tolerance to chemical disinfectants. Thereby dividing viruses into three viral subgroups. Using the Spaulding Classification model, microorganisms are tiered by their level of resistance to being killed (inactivation) by typical disinfectant products. (Spaulding) These subgroups are small non-enveloped, large non-enveloped, and enveloped based on their relative resistance to inactivation. This hierarchy emphasizes that any antimicrobial product that can kill a small, non-enveloped virus should be able to kill any large, non-enveloped virus or any enveloped virus. Similarly, a product that can kill a large, non-enveloped virus should be able to kill any enveloped virus. (See below)
Small, Non-Enveloped Viruses(<50 nm): These small, non-enveloped viruses can be highly resistant to inactivation by disinfection. Despite the lack of a lipid envelope, these organisms have a very resistant protein capsid. The following are viral families in the small non-enveloped subgroup: (1) Picornaviridae, (2) Parvoviridae, (3) Caliciviridae, (4) Astroviridae, and (5) Polyomaviridae.
Large, Non-Enveloped Viruses: Compared to small, non-enveloped viruses, these viruses are less resistant to inactivation by disinfection. Although they have a resistant protein capsid, their larger size (50-100nm) makes them more vulnerable than their smaller viral counterparts. The following are viral families in the large non-enveloped subgroup: (1) Adenoviridae, (2) Reoviridae, and (3) Papillomaviridae.
Enveloped Viruses: Enveloped viruses are the least resistant to inactivation by disinfection. The structure of these viruses includes a lipid envelope, which is easily compromised by most disinfectants. Once the lipid envelope is damaged, the integrity of the virus is compromised, thereby neutralizing its infectivity. The following are viral families in the enveloped subgroup: (1) Arenaviridae, (2) Bornaviridae, (3) Bunyaviridae, (4) Coronaviridae, (5) Filoviridae, (6) Flaviviridae, (7) Hepadnaviridae, (8) Herpesviridae, (9) Orthomyxoviridae, (10) Paramyxoviridae, (11) Poxviridae, (12) Retroviridae, (13) Rhabdoviridae, and (14) Togaviriedae.
Coronavirus vs Influenza
Both viruses are enveloped viruses and fall within subgroup viral families. The Coronavirus is an enveloped virus with a positive sense, single-stranded RNA genome. It has genome sizes ranging from 26 to 32 kilobases (kb) in length, CoVs have the largest genomes for RNA viruses. This means it can serve as messenger RNA and can be translated into protein in the host cell. (Schoeman)
The influenza A and B virus genomes each comprise eight negative-sense, single-stranded viral RNA (vRNA) segments, while the influenza C virus has a seven-segment genome. The influenza A, B, and Cviruses, representing three of the five genera of the family Orthomyxoviridae, are characterized by segmented, negative-strand RNA genomes that do not encode mRNA (messenger RNA). (Bouvier)
The main difference in these two viruses is the COVID-19: is caused by one virus now called severe acute respiratory syndrome coronavirus 2, or SARS-CoV-2. Influenza is caused by any of the several different types and strains of influenza viruses, which is serious because of its potential to harm many people and change abruptly resulting in a new human seasonal influenza.
Mitigation through Efficacy
It's crucial to have an effective cleaning and disinfection process in place before an outbreak. When choosing a product, efficacy should be the determining factor and not cost. Each cleaning chemical should be carefully selected based on the environment and types of microorganisms that could present themselves in that environment. It's essential to read the product's kill claim and product sheet in its entirety to ascertain whether that is the best choice for the environment. Many disinfectants are used alone or in combinations (e.g., hydrogen peroxide and peracetic acid). To ensure the inactivation of microorganisms the cleaning professional must adhere to the appropriate dwell/contact times. If a product does not display a kill claim on its label or has an efficacy sheet, more than likely, it is not a disinfectant, or it's not effective in the inactivation of a specific microorganism (s). (Strauthers)
Spaulding E.H. 1968. Chemical disinfection of medical and surgical materials. Disinfection,Sterilization, & Preservation, 3rd Edition, Block S (Ed), (Lea & Febiger, Philadelphia, PA).
Schoeman, Dewald, and Burtram C Fielding. “Coronavirus envelope protein: current knowledge.” Virology journal vol. 16,1 69. 27 May. 2019, doi:10.1186/s12985-019-1182-0
Bouvier, Nicole M, and Peter Palese. “The biology of influenza viruses.” Vaccine vol. 26 Suppl 4, Suppl 4 (2008): D49-53. doi:10.1016/j.vaccine.2008.07.039
Strauthers, Gloria. “Efficacy.” Cleaning for Health, Not Shine: A Systems Approach to Cleaning p. 15 (Strauthers)
Exodus is a cleaning solutions provider that evaluates cleaning programs and makes recommendations on the implementation of best practices to improve cleaning outcomes and lower the total cost of cleaning with a goal of adopting ISSA practices and principles to meet hygienic standards. Visit www.exodusmanagementconsulting.comto schedule your consultation today.