Coronavirus: Not all disinfectants as effective as claimed, says NEA

The NEA also noted that how disinfectants are applied is important, recommending a wipe-down of surfaces. ST PHOTO: KUA CHEE SIONG

Whether products being touted for use against coronaviruses actually work depends on their active ingredients, the concentration of these ingredients, and the right application. Not all products are as effective as claimed, the National Environment Agency (NEA) said yesterday.

"There are currently many chemical disinfectants and biological inactivation mechanisms marketed for disinfection of coronaviruses, (but) not all have been shown to be effective," an NEA spokesman said.

In an advisory to help the public make informed decisions, the agency stressed the importance of effective cleaning, citing a study by its Environmental Health Institute (EHI) which found that the virus can linger on frequently touched areas used by confirmed Covid-19 cases.

The study detected the virus in two out of more than 400 samples collected from frequently touched areas in non-healthcare accommodations used by Covid-19 patients. Subsequent sampling of the same surfaces after disinfection did not detect the virus.

"Laboratory tests by other researchers have shown that Sars-CoV-2 can survive on environmental surfaces for two to three days. Disinfection of spaces where Covid-19 cases dwell is thus essential," said EHI research scientist Judith Wong, who led the study.

NEA said how disinfectants are applied is important, recommending wipe-down of surfaces. Handheld misters or electrostatic sprayers are not adequate on their own and should be used only to supplement wipe-downs.

Antibacterial products do not kill viruses, which have a different chemical and biological make-up.

Last month, a self-disinfecting coating that is said to kill bacteria and fungi upon contact and last for up to three months was applied to buttons in all Housing Board lifts and lift lobbies in Singapore.

The coating was a donation to the 16 town councils by Changi Airport Group, which has been using the product in Changi Airport. Similar anti-microbial coatings have been applied on ATM buttons.

NEA said it has requested but not received "robust scientific evidence" on the effectiveness of such coatings against coronaviruses from the suppliers of such products.

It also included in its advisory a list of common household products and disinfectants, such as the Mr Muscle multi-purpose cleaner and Dettol antiseptic disinfectant liquid, with active ingredients like benzalkonium chloride and sodium hypochlorite that are effective against the coronavirus.

These products must contain the right concentration of an active ingredient to be effective. Different active ingredients also vary in the amount of time required to thoroughly disinfect a surface.

The public is therefore advised to read product labels to look for the active ingredients and their concentrations, to understand their hazards and to ensure that they meet NEA's guidelines for effectiveness against coronaviruses, the agency said.

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A version of this article appeared in the print edition of The Straits Times on May 23, 2020, with the headline Coronavirus: Not all disinfectants as effective as claimed, says NEA. Subscribe