YSN-ASM Science Café Johor | Hand Sanitiser: Fake or Genuine?

The Young Scientists Network-Academy of Sciences Malaysia (YSN-ASM) Science Café is a programme that aims to bring science to the public. Viewing its success in the Central Region of Peninsular Malaysia, the programme has since spread its wings to the southern region with the Science Café Johor. Science Café Johor is hosted via Zoom by Dr Jaysuman Pusppanathan and broadcasted via Facebook Live. This episode featured ChM Dr Shahrul Nizam Ahmad from the School of Chemistry and Environment, Faculty of Applied Sciences, Universiti Teknologi MARA (UiTM).

There is a plethora of hand sanitisers in the market nowadays. The advent of the COVID-19 pandemic saw the rise of small and medium enterprises joining more established brands to produce hand sanitisers to meet market demands and bite off some of the proverbial cake of profit. However, the lack of adherence information on what makes a good and effective hand sanitiser and the irresponsibility of some manufacturers that prey on unsuspecting customers by selling ineffective products necessitates the production of this Science Café session.

Hand sanitisers are portable liquid or gel products that are used to inactivate or kill microorganisms on your hands in the absence of soap and water. These products are alcohol-based, ethanol or isopropanol being the most popular main ingredient. To be effective, hand sanitisers need to have at least 60 percent alcohol content. There are also hand sanitisers that use antimicrobial agents such as benzalkonium chloride or benzethonium chloride in lieu of alcohol. However, these are much less effective compared to alcohol-based sanitisers.

According to Dr Shahrul, the formulation of hand sanitisers must follow the guidelines given by the World Health Organisation (WHO). A study was carried out on the inactivation of Severe Acute Respiratory Syndrome Coronavirus 2 by WHO-recommended hand rub formulations and alcohols. It was found that using a hand sanitiser for at least 30 seconds can effectively deactivate the novel coronavirus.

Bear in mind that hand sanitisers should be used when there are no facilities available for hand washing. The best method of killing the coronavirus is still hand washing, according to Dr Elizabeth Scott, PhD. Hand washing with soap employs mechanical action that loosens bacteria and viruses from the skin, rinsing them down the drain. Soap disrupts the sticky bond between pathogens and your skin, allowing the pathogens to slide right off. However, it is essential to wash your hands for at least 20 seconds.

Dr Shahrul also showed a WHO-recommended basic formulation of alcohol-based hand sanitisers. A basic formulation consists of ethanol 96% or isopropyl alcohol 99.8% (the main ingredient that inactivates pathogens), hydrogen peroxide 3% (used to inactivate contaminating bacterial spores in the solution and is not an active substance for hand sanitising), glycerol 98% (used as humectant, which is a moisturising agent for your skin) and sterile distilled or boiled cold water (solvent to mix everything together). Colourants are allowed to allow differentiation from other fluids, but these additives must be nontoxic, promote allergy or interfere with antimicrobial properties. Perfumes are not recommended due to risk of allergic reactions.

In between presenting, Dr Shahrul also accepted questions from viewers. One of the questions addressed was about the shelf life of alcohol-based sanitisers. Due to the evaporating nature of alcohol, the efficacy of opened alcohol-based sanitisers will diminish with time. Unopened hand sanitisers will last a bit longer but in view of the frequency of sanitiser usage, Dr Shahrul thinks a bottle of hand sanitiser will be finished way before it is too ineffective.

Next, Dr Shahrul presented on the issues that arises with alcohol-based sanitiser. Not all alcohol is suitable to be used in hand sanitisers; methanol is one example. When ethanol is absorbed by the skin, it will be broken down into an acid and isopropyl alcohol will break down into ketones which are relatively safe for humans. On the other hand, methanol breaks down into formaldehyde and then formic acid which are harmful to humans. Formaldehyde is a colourless, strong smelling gas that causes damage to the nervous system and is a known carcinogen (a substance that can cause cancer).

The next question addressed during the session was on public disinfection and risk towards public health. Dr Shahrul explained that public disinfection is a bit different from sanitising; the former usually involves usage of sodium hypochlorite (e.g. Clorox). He mentions the decontamination and sanitation tunnel as an effort to slow the transmission of the coronavirus sprays disinfectant in aerosol form to sanitise people who goes through it. However, the aerosol spray might be harmful to people when inhaled. Besides, the effectiveness of alcohol as a sanitising agent is dependent on how long it stays in contact on the surface e.g. skin and the aerosol method might not be as effective as using the liquid/gel form directly on the skin.

Dr Shahrul addressed the next question about any differences between a liquid and gel sanitisers assuming they both have 70% alcohol content. Dr Shahrul noted that both are equally effective, but he personally prefers the gel form because it may contain glycerol or other moisturising ingredients to improve user experience. Then, Dr Jaysuman mentioned the occurrence of shop owners who water down their hand sanitiser for public use and whether it will affect its effectiveness. Dr Shahrul explained that water is an essential component of hand sanitisers to ensure the miscibility of the hand sanitiser, but it must be ensured that the alcohol content remains at 60 percent or more.

Next, Dr Shahrul touched upon the halal status of alcohol-based hand sanitisers, an oft-mentioned topic by Muslim users in Malaysia. Citing the verdict by the federal mufti (a Muslim legal expert who is empowered to give rulings on religious matters), hand sanitiser is permissible to be used in prayers. Additionally, Dr Shahrul mentioned the rise of “religious riders” who prey upon people’s misinformation to produce hand sanitisers that are not in accordance with WHO guidelines. These products are often sold with additional ingredients that may or may not be effective against pathogens. Dr Jaysuman also adds on that some products do not have adequate alcohol content for it to be effective.

Dr Jaysuman raised a question about DIY hand sanitisers. Dr Shahrul mentioned that he is apprehensive about the ability of the regular person’s ability to produce hand sanitiser that is properly measured and effective, as well as their ability to observe the necessary safety precautions when handling chemicals such as high-percentage alcohol. Therefore, he echoed the Food and Drug Administration (FDA)’s recommendation and discouraged people from making their own hand sanitiser. It could be ineffective and may cause skin burns from improper handling of high-percentage alcohol.

Another issue rained by Dr Jaysuman is the flammability of alcohol-based hand sanitisers. Dr Shahrul reminded viewers that alcohol is a flammable substance. Therefore, he advised to avoid smoking or ignite fires near hand sanitisers. Also, store alcohol-based hand sanitisers in a properly ventilated, cool dry place with the container tightly closed.

Dr Shahrul concluded the session with a few take away messages:

• Washing your hands with soap and water should be your go-to whenever possible.
• Read labels to identify what kind of alcohol is used. This is to identify the alcohol type, the alcohol percentage and also for additives that will trigger your any chemical sensitivities.
• Purchase hand sanitisers from trusted brands and authorities.
• Check with the National Pharmaceutical Regulatory Agency (NPRA) Malaysia to ensure the safety of pharmaceutical and cosmetic products.