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Don't let guard down on germ defence at home for Christmas, urge researchers

11 December 2020

Behavioural psychologists behind the app Germ Defence are reminding people of the simple things we can do at home to help reduce infection spread at Christmas.

As people make plans to spend time indoors with their friends and family for a limited period over Christmas, behavioural psychologists are urging us not to become complacent about the virus risk and reminding everyone of the importance of germ defence.

The team from the universities of Bath, Bristol and Southampton who developed the app ‘Germ Defence’ say with the prospect of a limited, shared Christmas and a vaccine now being rolled out we cannot afford to let our guard down in allowing covid to spread.

Germ Defence – the only web-based advice in the world that’s been scientifically proven to work against respiratory infections – is designed to give personalised advice on how to protect members of a household from infection. This is crucially important right now in view of current restrictions as indoors at home is where infections are most likely to be transmitted.

This year their app was redeveloped for Covid-19, most recently in view of guidance for the Christmas period. This includes suggestions on reducing the virus risk at home in preparation by moving seating to enable social distancing, by keeping rooms well ventilated and by ensuring that surfaces are regularly cleaned. After visitors leave, it suggests cleaning surfaces but also leaving the windows open for at least one hour.

Germ Defence helps users make decisions and set goals that will work for them to reduce the levels of virus in the home. The results of a previous Lancet study of over 20,000 people highlighted that Germ Defence was shown to reduce the spread of swine flu and seasonal flu. People who followed its advice were less likely to catch flu or other viruses and less likely to pass it on to members of their household.

Dr Ben Ainsworth, from the University of Bath, who is leading the adaptation of Germ Defence for Covid-19, explained: “Lots of people will be looking forward immensely to seeing their family at Christmas, and making difficult decisions about how to do it safely. However, spending time inside with people means that it is now more important than ever not to let our guard down on essential germ defence within the home.

“Many of the methods to reduce levels of virus are simple, and will take seconds or a few short minutes, but we know they can make a real difference in how the virus spreads.”

In spring 2020, Germ Defence was updated for Covid-19, using input from members of the public and health experts, and funding from the National Institute for Health Research and UK Research Institute. The app recently reached a milestone of 250,000 users (who gave it an average rating of 8/10 for usefulness) and was also recently included within Public Health England’s guidelines for people self-isolating at home.

Professor Lucy Yardley from the University of Bristol's Centre for Academic Primary Care, who led the development of Germ Defence, said: “Many people don’t realise that there are things they can do quite easily that will really reduce the risk of spreading the virus when family and friends visit over Christmas. Germ Defence can help everyone and includes advice on what to do if someone in the household is infected or could become very ill if they are infected.”

Sascha Miller, who has been working with members of the public to make sure the advice is useful to them, said: “With winter and Christmas coming, we know that people are keen to learn how to make their home as safe as possible for all the family. Germ Defence provides practical advice on things like ventilation and social distancing to help people spend time together.”

Cathy Rice, a member of the public who joined the Germ Defence team to help shape its development and usefulness said: “It’s easy to feel overwhelmed when trying to protect ourselves and our families against Covid, but Germ Defence gives simple steps that really work. It only takes 10 minutes, it’s backed up by science, and it’s something everyone can do.’’

Germ Defence is freely available in more than 25 languages and accessible via

Further information

About the Centre for Academic Primary Care
The Centre for Academic Primary Care (CAPC) at the University of Bristol is a leading centre for primary care research in the UK, one of nine forming the NIHR School for Primary Care Research. It sits within Bristol Medical School, an internationally recognised centre of excellence for population health research and teaching. Follow us on Twitter: @capcbristol.

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