A year of leading the world’s largest symptom study of COVID-19

Last month marked one year since the launch of the ZOE COVID Symptom Study, a pioneering, app-based, scientific study into the spread and effects of COVID-19.

ZOE KHP socials one year on

The COVID Symptom Study app was developed by health company, ZOE, with King’s College London, and is delivered in close collaboration with King’s Health Partners. 

The study, which is unique in its peer reviewed methodology, uses community symptom monitoring to provide near-real-time estimates of COVID-19 incidence down to the local level. It is used alongside the ONS and REACT-1 studies to inform the UK Government and public health decisions. 

More than one million people joined the app on the day it launched and there are currently nearly five million contributors. 

Since its launch, the study has generated more than 40 scientific discoveries and linked 35 symptoms with COVID-19. The study has recorded: 

  • Data from 4,641,484 worldwide contributors with over one million average weekly users. 
  • 318,712,220 health reports. 
  • 1,076,169 vaccines. 
  • 4,586,014 test results including PCR, lateral flow and antibody tests. 

Watch the anniversary video which reflects on the study and highlights its continuing importance.  


Tim Spector OBE, lead scientist on the ZOE COVID Symptom Study app and Professor of Genetic Epidemiology at King’s College London, said: 

As COVID-19 took off in the UK, with numbers of cases and deaths rising, many people were left feeling helpless. I challenged the ZOE team to build an app that would empower anyone to join and make a meaningful impact on the pandemic. ZOE built the app in a few days and millions responded to our call to join the study. As a result, more than 40 scientific discoveries have been made, including getting anosmia added to the official list of COVID-19 symptoms.


Claire Steves, Reader at King’s College London, said: 

 The ZOE app is just as important today as it was a year ago. There are still many challenges and unanswered questions. We’re already looking at vaccines and how effective they are in the real population with almost a million doses logged with the study. We’re also looking at new variants. With enough participants continuing to log with the app, we’ll be able to detect outbreaks around the country and help prevent another national lockdown. 


Jonathan Wolf, Co-founder & CEO at ZOE 

I’m incredibly proud of the ZOE team and so thankful to the millions of people who joined the app when they were needed the most. Our shared success has undoubtedly saved lives. We are excited by the important scientific discoveries that continue to be generated and we hope we will have your continued support to make that happen.

If you have not yet downloaded the app, you can still do so for free from https://covid.joinzoe.com