Hand washing encouraged as hand sanitizer shown to be ineffective at killing the flu

A new study has found that hand sanitizer may not be as effective as previously thought at preventing the spread of influenza A, the common flu virus.

The evidence emerged this month following a study led by a team of scientists at the Kyoto Prefectural University of Medicine, which showed that rubbing hands with antiseptic, ethanol-based disinfectant sanitizer is not as effective as antiseptic hand washing.

The results are important because they suggest that the current protocol for disinfecting hands is not effective enough to prevent the spread of the flu virus. The study’s findings call into question the effectiveness of alcohol-containing hand sanitizer products in protecting against viruses and bacteria.

Hand washingAlexander Raths | Shutterstock

Hand rubbing vs. hand washing

It has previously been claimed that antiseptic hand rubbing was more effective than antiseptic hand washing at fighting viruses and bacteria. However, the new study contradicts these claims.

Researchers applied the infected mucus of patients with the influenza A virus to the fingertips of volunteers. They found that the mucus acted to protect the virus from the effects of ethanol-based hand sanitizers.

It was found that 4 minutes of contact between the virus and the sanitizer was necessary in order to deactivate the virus. Conversely, they saw that antiseptic hand washing rapidly deactivated the influenza virus. The Japanese team also showed that deactivation of the virus was not achievable until the mucus had dried.

These findings carry major implications for healthcare professionals. They suggest that hand rubbing may not be effective in preventing the spread of influenza between patients, especially if time is not taken to completely dry the hands in between patients.

The findings suggest that hand washing should always be carried out between patients. The current recommendations allow healthcare professionals to use hand sanitizer if they are short on time, which may need to be addressed following this study.

How dangerous is influenza A, or 'the flu'?

Nearly every winter the US, and other nations, face seasonal outbreaks of the flu. These outbreaks are generally type A, the kind the Japanese team focused on, and also type B. In addition to this, influenza pandemics have been shown to be caused by new strains of the A virus.

Flu infection is often trivialized as the symptoms of influenza A infection can often be confused with other conditions, and people may claim to be suffering from the flu when actually their symptoms are due to a milder condition, such as a cold.

Common symptoms include a fever, a sore throat, and runny or stuffy nose, coughing, headaches, fatigue, chills and aches over the body.

Worryingly, in severe cases, infection of type A influenza can be fatal. 2017 saw the highest number of people losing their life to flu in the US for decades, with the virus claiming the lives of 80,000 people from 2017-2018, including 180 children.

The previous high was recorded around 30 years ago, where 56,000 died from the virus. During the 2017-2018 season the US hospital system was overwhelmed with cases, leading to some hospitals being forced to pitch tents in order to treat the sheer number of patients.

These figures highlight why preventing the spread of influenza is so essential. Proper sanitization in hospitals can prevent the spread of the virus which has been proven to pose a significant threat to human life, especially within those who have a weakened immune system, such as hospital patients.

We know that those infected with the flu can be contagious from a day before the symptoms present themselves until a week after or longer. This relatively long infectious window makes proper sanitization even more fundamental to preventing the spread of infection.

Take home message

It has previously been claimed that hand sanitizers are an effective defense against the spread of infectious viruses and bacteria. For this reason, they have been integrated into routine hygiene systems in hospitals.

However, this new evidence shows that they are not effective at deactivating the influenza A virus, and the findings suggest that hand washing should be favored over the hand rubbing method.

While some experts argue that rubbing with hand sanitizer is effective when you consider that generally people do not wash their hands for a long enough time to deactivate viruses, the research coming out of the Kyoto Prefectural University of Medicine clearly shows that with hand rubbing, the sanitizer must be in contact with the virus for four minutes for it to be effective, whereas with hand washing this is much faster.

Journal reference:

Hirose, R., et al. (2019). Situations Leading to Reduced Effectiveness of Current Hand Hygiene against Infectious Mucus from Influenza Virus-Infected Patients. Applied and Environmental Science. https://msphere.asm.org/content/4/5/e00474-19.

Sarah Moore

Written by

Sarah Moore

After studying Psychology and then Neuroscience, Sarah quickly found her enjoyment for researching and writing research papers; turning to a passion to connect ideas with people through writing.


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