Like other coronaviruses, SARS-CoV-2 is an enveloped virus with a fragile outer lipid envelope that makes it more susceptible to disinfectants compared to non-enveloped viruses such as rotavirus, norovirus and poliovirus

Quaternary ammonium compounds (QACs) are primarily bacteriostatic and fungistatic, although they are microbicidal against some organisms at high concentrations. They are more active against Gram-positive bacteria than against Gram-negative bacilli. QACs have relatively weak activity against mycobacteria and fungi and have greater activity against lipophilic viruses. Their antimicrobial activity is adversely affected by the presence of organic material, and they are not compatible with anionic detergents. Depending on the QACs type and formulation, the antimicrobial efficacy can be severely affected in the presence of hard water (if it is a diluted product) and fatty materials. Later generations of QACs, e.g. didecyldimethyl ammonium chloride (DDAC), have stronger antimicrobial activity and good performance in the presence of hard water and organic soiling, but their activity has been studied on inanimate surfaces only.

In general, QACs are relatively well tolerated. Unfortunately, because of weak activity against Gram-negative bacteria, benzalkonium chloride is prone to contamination by these organisms and a number of outbreaks of infection or pseudo-infection have been traced to QACs contaminated with Gram-negative bacilli.

Evidence from both the SARS and COVID-19 epidemics, shows that hand hygiene is very important to protect health care workers from getting infected (Seto WH et al, “Lancet” 2003; Ran L et al, “Clin Infect Dis” 2020).

Hand washing in the community is highly effective to prevent both diarrhoeal diseases and respiratory illness (Jefferson T, et al. “BMJ” 2008). Thus, it is one of the most important measures that can be used to prevent COVID 19 infection.

Alcohol-based hand rub products should contain at least 60% alcohol, should be certified and where supplies are limited or cost prohibitive can be made locally by carefully following WHO Guide.

Plain soap is effective at inactivating enveloped viruses such as the COVID-virus due to the oily surface membrane that is dissolved by soap, killing the virus (Sickbert-Bennett EE et al, “Am J Infect Control” 2005). In addition, hand washing removes germs through mechanical action (WHO Guidelines on Hand Hygiene in Health Care 2009).

Chlorinated water at 0.05% is not recommended for routine hand hygiene because it has skin and other toxic effects, and soap is easy to find and can be used effectively

Sources:

WHO guidelines on hand hygiene in health care - https://www.who.int/infection-prevention/publications/hand-hygiene-2009/en/

Cleaning and disinfection of environmental surfaces in the context of COVID-19 - https://www.who.int/publications-detail/cleaning-and-disinfection-of-environmental-surfaces-inthe-context-of-covid-19

Interim recommendations on obligatory hand hygiene against transmission of COVID-19 - https://www.who.int/who-documents-detail/interim-recommendations-on-obligatory-hand-hygiene-against-transmission-of-covid-19