consult the most up to date European standards. These have been developed and defined through a process of sharing knowledge and building consensus among technical experts.

Enveloped vs. non-enveloped viruses When considering disinfectant selection, some understanding of the nature of viruses is helpful. Coronaviruses including SARS-CoV-2 are known as ‘enveloped’ viruses, whereas viruses including rotavirus and poliovirus are described as ‘non-enveloped.’ Coronaviruses have an outer lipid layer,

which forms a coating or ‘envelope’ which allows the virus to attach to a host cell. Viruses need a living host to be able to multiply. A virus particle attaches to the host cell before penetrating it, then uses the host cell to replicate its own genetic material. That process slowly uses up the host’s

cell membrane and usually leads to cell death. Once the virus has left the host cell it is ready to enter a new cell and multiply again. As the envelope is needed for host cell attachment, loss of this envelope results in loss of infectivity. Research has suggested enveloped viruses have the potential to develop significant environmental resistance, with the ability to survive in different environmental conditions and on different materials found in hospital settings such as aluminium, sterile sponges, latex surgical gloves as well as in biological fluids. That makes human coronaviruses

(HCoVs) ‘a challenging model for the development of efficient means of prevention’,5

underlining the importance

of optimum disinfectant choice. The main function of a disinfectant lies in its ability to kill or inactivate microorganisms. Therefore, a key step in the selection process is ensuring the disinfectant has the required level of biocidal activity. Disinfection manufacturers provide efficacy data relating to both contact time and the required concentration. This data should be based on product testing which is both rigorous and repeatable.

Setting standards In Europe, this means being tested to the European Norms (EN). Despite the UK’s departure from the EU, European Norms will continue to provide ‘gold standard’ tests for disinfectants, for the foreseeable future.

A useful starting point for selecting a

disinfectant for hospital use in the COVID- era is the EN standard named EN14476 (2013+A2:2019). This European Standard specifies the minimum requirements for the virucidal activity of a chemical disinfectant. It applies to areas where disinfection is

114 Chemical laboratory.

medically indicated including patient care in hospitals. A disinfectant which has this EN certification will be effective against enveloped viruses including SARS-CoV-2. Disposable, single-use disinfectant

wipes are a convenient option for surface decontamination in hospitals. The required contact time of a wipe certified to EN14476 should be considered. This is the time required for the

solution to be in contact with pathogens in order to eliminate or inactivate them. The contact time could vary from 30 seconds to five minutes, which is not a practical amount of time in a busy clinical setting).

It is not only the disinfectant content of a wipe which affects efficacy, but also the actual composition and material of the wipe has an impact on the ability of the wipe to mop up and hold pathogens rather than just spreading them over the wiped area. The EN16615: 2015 test provides the

highest level of testing for antimicrobial, ready-to-use wipes. The test examines the efficacy of the wipe as a whole - the wipe itself plus the disinfectant component. It cannot be assumed that all clinical use wipes will be certified to both EN16615 and EN14476. Those which do not comply to both norms may not be fit for purpose, which is not a risk worth taking during a coronavirus pandemic. When referring to European Norms, it is essential to make product comparisons

based on testing to the most up to date standards. Over time, standards become increasingly rigorous, to protect both patients and staff, but there is no mandatory requirement for manufacturers to test to the latest standards. Newer and more rigorous standards may recommend increased disinfectant concentrations and longer contact times, to ensure microbial efficacy.

Choosing the optimum disinfection

product may mean that a number of different ones are required depending on the surface to be cleaned. For example, ethanol shows a significant activity on the human coronavirus5

so a virucidal

disinfector/cleaner containing ethanol, such as mikrozid®

wipes may play a useful

role in the cleaning and disinfection of hard surfaces, particularly as it is effective against enveloped viruses within one minute (EN14476). Conversely, alcohol-free wipes may be

needed to clean and disinfect surfaces sensitive to alcohol like leather, PVC and acrylic glass. A low-alcohol disinfectant may be utilised where a material friendly disinfectant is required such as patient treatment units and sensitive, high-value equipment. Whatever type of disinfectant is selected, it should still meet the requirements defined in EN14476 for virucidal efficacy.

Conclusion Until an effective, universally accessible vaccine is available, it is highly likely that COVID-19 will remain a threat for the foreseeable future. The highest standards of infection prevention in healthcare facilities is therefore essential, including the selection of optimum disinfectants. Referring to the latest EU standards can help simplify the process.


References 1 Public Health England. COVID-19: guidance for health professionals, 2020 wuhan-novel-coronavirus.

2 Kraay ANM, Hayashi MAL, Hernandez-Ceron N et al. Fomite-mediated transmission as a sufficient pathway: a comparative analysis across three viral pathogens. BMC Infect Dis 2018; Oct 29; 18 (1): 540.

3 Kampf G, Todt D, Pfaender S, Steinmann E et al. Persistence of coronaviruses on inanimate surfaces and their inactivation with biocidal agents. J Hosp Infect 2020; 104 (3): 246-51.

4 van Doremalen N, Bushmaker T, Morris DH et al. Aerosol and surface stability of SARS- CoV-2 as compared with SARS-CoV-1. N Engl J Med 2020; Apr 16; 382 (16): 1564-7. doi:10.1056/NEJMc2004973

Petri dishes.

5 Geller C, Varbanov M, Duval RE. Human Coronaviruses: insights into environmental resistance and its influence on the development of new antiseptic strategies. Viruses 2012; 4 (11): 3044-68.


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