Headaches, a sore throat and a runny nose are the most common symptoms associated with the UK’s most widely established Covid variant, researchers have said.
The data, collected as part of the app-based Zoe Covid symptom study, suggests that the Delta variant first detected in India feels like a “bad cold”, according to Tim Spector, a professor of genetic epidemiology at King’s College London, who is leading the work.
“Covid is … acting differently now, it’s more like a bad cold,” he said. “People might think they’ve just got some sort of seasonal cold, and they still go out to parties … we think this is fuelling a lot of the problem. So, what’s really important to realise is that since the start of May, we’ve been looking at the top symptoms in all the app users, and they’re not the same as they were. So, the number one symptom is headache … followed by sore throat, runny nose and fever.”
Watch: COVID-19 - Delta variant increases hospitalisation risk but vaccine protection remains high, study suggests
According to the NHS, the classic Covid symptoms are fever, cough and loss of smell or taste.
Spector said that with Delta, a cough appears to be the fifth most common symptom, and the loss of smell doesn’t make the top 10.
Data suggests that the Delta variant is at least 40% more transmissible than the Alpha variant first detected in Kent, and appears to double the risk of hospitalisation. It also renders vaccines somewhat less effective, particularly after only one dose.
The rapid, priority-based rollout of vaccines in the UK means that although high numbers of the elderly population are fully vaccinated, younger adults are probably partially vaccinated or unvaccinated for now. According to a Guardian analysis, two-thirds of the population in England are still not protected by vaccines against symptomatic infection from the Delta variant.
“I think the message here is that if you’re young and getting milder symptoms any way, it might just feel like a bad cold or some funny feeling … do stay at home and do get a test,” Spector said.
The app, run by the health science company Zoe – founded by Spector – with scientific analysis provided by King’s College London, has more than 4 million contributors globally.
According to data published on 10 June, cases are higher and increasing faster in the unvaccinated population within the UK. Cases have increased the most in the 20-29 age group, and the 0-19 age group follows closely behind, according to data collected from participants between 23 May and 5 June (this excludes data from rapid tests).
These rising case numbers are probably rooted in the higher rate of transmission and fatigue around social distancing. Data from the Office for National Statistics shows the proportion of adults in Great Britain maintaining social distancing with people outside their household fell to 68% over the period 2-6 June, compared with 74% the week before.
Watch: What UK government COVID-19 support is available?