The research hopes to help understand the ‘hidden iceberg’ – alongside the ill, the number of adults who may already have had COVID-19 without ever knowing they had it or with mild symptoms.

There is highly likely a hidden iceberg of asymptomatic people who may have unknowingly had the virus before the pandemic started. Understanding the size of this group will help the government plan how to tackle the virus going forward.

The Children of the 90s questionnaire will reveal how many of the study’s predominantly healthy, young study participants experienced COVID-19 like symptoms in the past six months. Over 13,000 questionnaires will be emailed to study’s young adults (the ‘Children of the 90s’ who are aged 27-29) and their parents over the next few weeks.

The findings will give the government a clearer understanding of prevalence of COVID-19. From the data, public health experts hope to be able to estimate more accurately how many people are yet to contract the virus, which will indicate the timings for any future lockdown strategy.

In the longer term, the questionnaire and subsequent follow-up will also examine how participants’ physical and mental health may have been affected by the government’s lockdown strategy and the economic downturn caused by the virus. Researchers will use the data to understand the psychological, social and economic impacts of the pandemic and the restrictions that have been put in place to reduce its spread.

Scientific lead for Children of the 90s study, Professor Nic Timpson said: “Bristol should be enormously proud to be home to one of the world’s leading health studies. Children of the 90s participants and their families have contributed to vital medical research all their lives.  Now our participants can really make a difference in the fight against COVID-19.

 “Please fill in our latest COVID-19 questionnaire. and encourage all your friends who are in the study or your family to do the same. You can also get back in touch with us if you’ve not done anything for a while – each and every completed questionnaire will help. Text your date of birth to 07772 909090 or visit childrenofthe90s.ac.uk.”