Updated: See the latest stories on the coronavirus outbreak.

People across the UK can now self-report coronavirus symptoms to an app to monitor whether they might have the virus, but also aid research into how it’s spreading.

The app, called Covid-19 Symptom Tracker, has been designed by doctors and scientists at King’s College London (KCL) and Guys and St Thomas’ Hospitals, and can be downloaded on both Apple and Android phones.

People are urged to download the free app and take a minute each day to self-report how they’re feeling – even if they are feeling well.

The app aims to figure out: where the high-risk areas are in the UK right now, who is most at risk, and how fast the virus is spreading in specific areas.

Users are asked a mixture of questions including their name, year they were born, height and weight, as well as some more generalised questions about their health – for example, if they have diabetes, heart disease or smoke. They are then asked how they are feeling today.

All of the data is then submitted to researchers who can assess where the virus might be spreading more quickly in certain parts of the UK.

Around 5,000 twins and their families across the UK have also been recruited to trial the app. They will go one step further than the rest of the public and record symptoms like temperature, tiredness and symptoms such as coughing, breathing problems or headaches.

Any of the twin participants showing signs of Covid-19 will be sent a home testing kit to better understand what symptoms truly correspond to the coronavirus infection.

Why twins?

Comparing genetically identical twins with non-identical twins, who are as related as regular siblings, will help researchers to separate the effects of genes from environmental factors such as diet, lifestyle, previous illnesses and infections, and the microbes within the gut.

Samples taken from the twin group will be used to generate a biobank for use in future research projects investigating infection and immune responses.

Researchers hope the data will reveal important information about the symptoms and progress of the virus in different people, and will help to explain why some go on to develop more severe or fatal disease while others have only mild symptoms.

Another key aim is to help distinguish mild coronavirus symptoms from seasonal coughs and colds, which may be leading people to unnecessarily self-isolate when they aren’t infected or inadvertently go out and spread the disease when they are.

Tim Spector, professor of genetic epidemiology at KCL, said: “These are worrying times for everyone. Our twins are fantastically committed, enthusiastic health research participants who have already been studied in unprecedented detail, putting us in a unique position to provide vital answers to support the global fight against Covid-19.

“The more of the public that also use the app, the better the real-time data we will have to combat the outbreak in this country.”