COVID-19: What household cleaning products can inactivate SARS-CoV-2 on surfaces?

COVID-19: What household cleaning products can inactivate SARS-CoV-2 on surfaces?
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Two years into the pandemic, we are all well aware of the basic measures we can take to mitigate the risk of contracting or spreading COVID-19: getting vaccinated, wearing a mask, washing your hands and regularly disinfecting shared surfaces are some of the simplest ways we can protect ourselves against the virus.

With COVID-19 now well-established in New Zealand, many Kiwis have had to share a home with an infected family member, flatmate, friend or partner under the Government's seven-day home isolation protocols. During this time, disinfecting commonly used surfaces - such as kitchen benches, bathroom fittings and door handles - is an important step to minimise the risk of other household members contracting the virus. 

But what products should we actually be using in our homes? Is that store-bought bottle of kitchen spray really effective enough to inactivate the virus?

For the most part, yes - but there are a few caveats.

Researchers from The Peter Doherty Institute for Infection and Immunity in Melbourne, Australia have tested the effectiveness of common cleaning products and their ability to inactivate SARS-CoV-2 - the virus that causes coronavirus disease, or COVID-19 - on household surfaces.

The research found that detergent, bleach and alcohol are highly effective at deactivating coronavirus-containing particles and droplets of respiratory fluids, which are released from an infected person's mouth or nose when they breathe, speak, cough or sneeze.

As home isolation continues to be utilised as a tool to reduce transmission of COVID-19 in public health responses across the globe, the researchers said it was time to make scientific findings more accessible and relevant to the general public.

Published in the latest issue of Viruses by MDPI, the research - led by University of Melbourne Dr Julie McAuley, a senior researcher at the Doherty Institute - marks one of the first studies to focus its testing on cleaning chemicals typically found in the home and used to decontaminate surfaces.

A survey led by the US Centers for Disease Control and Prevention (CDC) revealed more than 80 percent of respondents did not feel well-informed on how best to disinfect their home to prevent SARS-CoV-2 transmission, despite increasing their cleaning efforts.

To address this issue, Dr McAuley's research team tested the ability of cheap and readily available household cleaning products to render SARS-CoV-2 non-infectious, including vinegar, bleach, dishwashing detergent and ethanol, which represented alcohols typically used in households for cleaning purposes. 

"Our findings show that detergent, bleach and alcohol are highly effective at making SARS-CoV-2 non-infectious, but vinegar does not work at all," Dr McAuley said.

Dr Julie McAuley testing the cleaning products as part of the study.
Dr Julie McAuley testing the cleaning products as part of the study. Photo credit: Supplied / Phoebe Powell

The findings also revealed the minimum concentration of a diluted cleaning product that is still effective at killing SARS-CoV-2.

"To make an effective cleaning solution, it's as simple as adding a similar amount of detergent to water as you would for your dishes (2mL in 1 litre), then wiping over the potential SARS-CoV-2 contaminated surface and allowing it to dry," Dr McAuley said.

"For bleach, our results show that as little as 5mL can be added to 1 litre of water and could be ideal to disinfect bathroom surfaces. Alcohol containing handwashes, or solutions used for cleaning surfaces, must contain more than 40 percent alcohol to be effective."

The study also tested whether combining household products would increase their effectiveness. However, the research found there was no benefit.

"Surprisingly, when we combined bleach and detergent, we did not see increased virucidal potential for inactivating SARS-CoV-2 compared to using each component on their own," Dr McAuley said.

"We must also warn against combining chemicals in an attempt to increase their virucidal activity, as some household disinfectants contain buffering agents that we found may counteract the effective virucidal concentration of the other chemical it was mixed with."

All dilutions, products and combinations tested by the researchers have been published in the study and are available for the public to use to inform their COVID-19 cleaning plans.

"We wanted to provide all the information required to assist people to safely clean potentially contaminated surfaces, reducing the potential for transmission in their homes and workplaces."