The top Delta variant symptoms reported in the UK are a runny nose and headache – because most people affected are very young or partially vaccinated

• The Delta variant has taken over in the UK where the most common symptom reported is now a headache.
• Most people who are getting COVID-19 in the UK are quite young, and not fully vaccinated.
• Health experts are worried Delta could hit less vaccinated areas of the US very hard.
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The Delta variant first identified in India has taken over in the UK, where it’s now responsible for over 95% of infections. Delta’s also coming for the US fast, already accounting for more than 20% of sequenced cases, with a doubling time of about two weeks.

But King’s College epidemiologist Tim Spector says don’t be surprised if it shows up with different COVID-19 symptoms than those we’ve come to expect.

His latest research suggests that a headache and a runny nose are now two of the leading indicators of a COVID-19 infection across the UK, especially among the young and the partially vaccinated.

Spector’s research draws on daily illness data from more than a million people across the UK, who log into his ZOE app every day and report on how they’re feeling. ZOE’s research suggests about 19,000 people in the UK now catch COVID-19 every day. Most of them are young, and most are also not fully vaccinated.

“It’s evolved to be more infectious, which is what many viruses do,” Spector said, noting that the Delta variant may be roughly twice as infectious as its early predecessors, with each person who catches it transmitting to about six others.

“There’s no hard evidence yet that it’s more lethal or fatal, but because of that extra stickiness, it’s going to still keep breaking through,” he said.

Milder symptoms

According to ZOE’s latest data, from June 19, the COVID-19 case rate in the UK is now highest in the 20 to 29 age group.

“We’re seeing this mainly in young people who are unvaccinated, they are three quarters of the cases,” Spector said. “There’s hardly anyone who’s over 60 who’s getting it without a vaccine.”

Most of the people who test positive for COVID-19 in the UK are also weathering the traditional signs of a bad cold – headaches, runny noses, and sore throats – rather than the earlier tell-tale COVID-19 symptoms: shortness of breath or loss of taste.

It’s tough to know, though, if the Delta variant is truly becoming a milder disease, or if this is just how COVID-19 presents among the young, the healthy, and those with vaccine protection.

“Our hope is it’ll get milder,” Spector said. “So it will just become like a cold.”

The ‘most able and fastest and fittest’ variant

Disease watchers at the World Health Organization agree with Spector – yet another reason to get more of the world’s most vulnerable people vaccinated fast.

“The Delta variant is the most able, and fastest, and fittest,” Mike Ryan, executive director of the WHO’s health emergencies program, said on Monday, stressing that vaccines are still “highly protective against hospitalization and death,” even with variants in play.

“This particular Delta variant is faster, it is fitter, it will pick off the more vulnerable more efficiently than previous variants,” Ryan said. “And we can protect those people now.”

In the UK, nearly three quarters of adults have had both COVID-19 shots, giving them strong armor against severe COVID-19 disease and death. But so far only 16 US states have gotten 70% of adults any vaccine protection.

“This virus isn’t going to give up easily.” Spector said. “I don’t think we can be too complacent, particularly in areas of the US that have high non-vaccination rates.”

CDC Director Dr. Rochelle Walensky stressed in a White House COVID-19 briefing on Tuesday that “nearly every death” from COVID-19 in the US is now preventable. But time could be running out to ramp up protection, and the race with increasingly fitter variants is not over.