Coronavirus rates among young people are rising in Cornwall and Devon, official figures and health bosses say.
In Devon, overall rises in the county were being driven by cases among 10 to 14-year-olds, officials said.
Cases in Cornwall keeping it above the England average were high among 10 to 19-year-olds, figures revealed.
The statistics come as a senior doctor in Devon says the NHS is "in big trouble" as cases increase and health staff prepare for winter pressures.
Dr Ian Higginson, vice president of the Royal College of Emergency Medicine and a consultant at University Hospitals Plymouth, said he was concerned over the ability of the NHS in England to cope over the next few months.
He said: "There's no question that the words 'winter pressure' do not cut it any more.
"Whether you say it's failing or it's going over the edge of a precipice; however, you describe it, we know that the NHS is in big trouble throughout the country."
The Covid infection rate in Cornwall and the Isles of Scilly is 551 in every 100,000 people in the week to last Friday, higher than the England average of 466.
But the county has seen a jump in cases among 10 to 19-year-olds, with officials figures showing that age group to have 250 cases per 100,000 people.
All other age groups are at or under 100 per 100,000.
Covid rates have increased across most of Devon, although, overall, cases are similar to the national average.
However, Steve Brown, Devon's director of public health, said the rise was being driven by a high number of positive cases "among 10 to 14-year-olds in particular".
And false negative results from PCR tests at a Wolverhampton laboratory, with most of the 43,000 affected living in the South West of England, may have also affected statistics.
'Right' bed use
Emergency departments have been under sustained pressure recently, with Derriford's seeing 320 patients in 24 hours this week, the hospital said.
The Royal Cornwall Hospital said it had had to deal with twice the number of patients than the emergency department was built for.
Cornwall emergency department consultant Andy Virr said there were long-term plans to create more wards in other hospitals, including Bodmin, to relieve pressures.
He said there was a need to keep emergency departments "for what it says on the tin... for life-threatening emergencies on the day" and more social care was needed to help "ensure every bed is used in the right way".
The counties saw special measures for five weeks to tackle a Covid-19 spike, but those have ended.
National health leaders have warned some Covid restrictions must immediately be reintroduced to avoid a winter crisis, but the government has rejected this.
People are being urged to use non-urgent health services where possible.
Hospital bosses have said people could help free up beds by collecting relatives who were ready to go home.