Speakers: Prof Tim Spector & Prof Andy Chan

Our COVID Symptom app is collecting data about the coronavirus pandemic in the UK and the US  - two countries that share a language but have very different health systems and approaches to the crisis. 

In the latest episode of our Research Webinar series we spoke to Professor Tim Spector from King’s College London, who is leading the UK research behind the app, and US study lead Professor Andy Chan from Harvard School of Public Health, to find out more about the differences and similarities between the research strategies and data from the two countries so far.‍

Getting Brits and Americans to use the app‍

The COVID Symptom app was initially developed by Tim and his colleagues at King’s College London and the health science company ZOE for monitoring symptoms of coronavirus in the TwinsUK cohort - the biggest study of its kind in the world, involving nearly 15,000 identical and non-identical twins.

The app was quickly rolled out for the general public, and we now have nearly 3 million users checking in daily to report on their health, providing a hugely valuable dataset from across the UK.

In the US, the app launched a little later with a different approach. Andy and his colleagues at Harvard and Massachusetts General Hospital have focused on recruiting people from existing large-scale scientific studies, starting with the Nurses' Health Study - a group of many thousands of nurses across the US who have been contributing information about their lifestyle, diet and health since 1976.

“In addition to the Nurses' Health Study, we've also engaged with 15 other cohorts across the country, with participants that are currently providing data on a variety of risk factors,” Andy adds. ‍

Uptake in the US and UK‍

While the number of COVID Symptom app contributors has levelled off recently in the UK, the number of contributors in the US continues to grow steadily, with around 150,000 current registered users.‍

There are some areas of the US where we have enough users to be able to report useful data, but in other places, there aren't enough contributors yet.‍

“I think this reflects both the networks of collaborators we've engaged but also the interest in specific parts of the country,” says Andy “We're hoping to continue to roll this out much more broadly among the US population, as we’ve done in the UK.”‍

Are the symptoms of COVID the same in the US and the UK? ‍

Data from the app is providing critical information about the symptoms of COVID-19, and helping to identify people who are likely to be infected even in the absence of a coronavirus test.

For example, we previously highlighted how loss of taste and smell seem to be particularly important symptoms in the early stages of COVID-19, as part of a cluster of other symptoms including persistent cough, tiredness and skipping meals.‍

Reassuringly, this observation seems to hold up across the Atlantic.

“Looking between the two countries, the overall complex of symptoms and whether that predicts COVID-19 seems to be quite similar,” explains Andy.‍

Where are the people with COVID symptoms?‍

In the UK,  we’ve seen urban areas like Birmingham and London particularly hard hit by COVID-19, although symptoms now seem to be dropping significantly across all four nations.‍

In the US, areas like Massachusetts, New York, and some states in the South are the most worrying hotspots. Worryingly, some of the areas where the COVID Symptom app data is showing a high number of likely cases are also regions where coronavirus testing doesn’t seem to be widely available.

“What's key is that even though some of these areas have a large burden of symptoms, there's a mismatch in terms of the number of people who have reported getting tested, compared with the symptom burden, and that’s a major concern,” says Andy. ‍

How can symptom monitoring help us tackle the disease in the US and the UK?‍

“If we continue to have this crippling lack of testing across the country, we have the option to use symptom reports to predict where incidents of COVID are greater, and to understand where the next hotspots will be, which can be used to address this lack of testing,” Andy explains

As cases of the virus start to decline, data from the app can be used to understand whether we can begin to loosen lockdown restrictions - an increasingly controversial topic in a number of states.

“I think it can provide information that can get more of the country opened faster, but in a safe way,” he adds

New insights about COVID-19 risks coming from the COVID Symptom app data‍

Data from the Nurses Health Study, combined with UK healthcare worker data, has highlighted that medical professionals are at a very high risk of developing COVID. This points to an urgent need to ensure that healthcare workers have access to proper personal protective equipment (PPE) in order to do their life-saving jobs as safely as possible. 

“Until we had this data from the COVID Symptom app, we actually didn't how much higher the risk was if you were a healthcare worker," explains Andy.

The TwinsUK participants have also been providing ground-breaking information about why people respond so differently to the virus. 

“We've got our first analysis of around 3,000 twins who took part in the symptom app, and we've worked out that about half of the differences in how the virus presents between people are due to genetic factors,” says Tim. ‍

What’s next?‍

Ultimately, we need as many people as possible to download the COVID Symptom app and check in daily, whether you feel well or have any new symptoms. You can also set up separate user profiles within the app for any friends or family members who want to take part but aren’t able to access it.

“This data is important and will only be enriched with greater participation,” stresses Andy. 

We are continuing our work with our cohorts in the US and the UK, hoping to use their past and current data to enhance our understanding of COVID-19. 

For our healthcare workers, we will be looking at whether access to specific types of PPE reduces their chances of catching the disease. 

We will also be using blood samples provided by TwinsUK participants to look at whether particular genes affect individual responses to COVID-19 and how our immune systems react to the virus differently. 

We will also continue to dive into data from the general public, and as restrictions begin to ease, we will be watching for changes in our data. 

We also want to get more people using the app and cover more countries. Our latest launch was in Sweden last week - this could provide a fascinating contrast because, unlike the UK and the US, the Swedish Government has not enforced lockdowns or shelter-in-place orders.‍

To sum up

• In the UK, nearly 3 million ‘stay at home scientists’ are logging their health using the COVID Symptom app, providing comprehensive data about the symptoms and spread of COVID-19
• In the US, fifteen large-scale study groups are now using the app, giving insights into how coronavirus interacts with several key risk factors and health conditions.
• We are starting to gather valuable information about early symptoms, risk factors, and testing coverage from both US and UK data.
• In the coming weeks, we will be adding to our research efforts and diving deeper into the data to gain more insights into the disease
• The app may provide the rapid data that can help decision-makers to allocate resources and lift lockdown restrictions in the UK and the USA 
• To make this work, we need as many people as possible to be logging their health daily through the app
  

Watch the full webinar online now.

Find out more:

• Rapid implementation of mobile technology for real-time epidemiology of COVID-19  –MedRxiv
• Geo-social gradients in predicted COVID-19 prevalence and severity in Great Britain: results from 2,266,235 users of the COVID-19 Symptoms app – MedRxiv
• US Data by State - COVID Symptom Research blog
• Protecting healthcare workers from COVID-19 - COVID Symptom Research blog
• Genetics and COVID-19 symptoms - COVID Symptom Research blog
• Self-reported symptoms of covid-19 including symptoms most predictive of SARS-CoV-2 infection, are heritable – MedRxiv
• Study of twins reveals genetic effect on Covid-19 symptoms – The Guardian