As health boards across the country feel the strain, it is thought the spike of infections during the Euro 2020 championships may not yet have translated into hospital admissions.
One doctor said they are seeing people in their 20s and 30s “getting really quite sick with Covid”, as health boards warned of younger people in hospital and intensive care.
The Royal College of Paediatrics and Child Health (RCPCH) also expects already-struggling hospitals to see a wave of non-Covid viruses in children and babies as schools return in August.
Roughly two-thirds of Covid cases are now in under 25s, and the number of young people in hospital with Covid has increased steadily since April.
It comes after Professor Linda Bauld of Edinburgh University warned Scotland “is going to see more people in hospital over the next few weeks”.
Nicola Sturgeon will update MSPs on Covid-19 on Tuesday, when she is expected to confirm the planned move to level 0 restrictions across Scotland on July 19.
The RCPCH said it is concerned about young adults with Covid, and non-Covid viruses in children.
While there has been a recent increase in children in hospital with Covid, the College said this is less worrying, as often children are admitted to hospital for another reason and happen to also have Covid, while their young parents may be suffering much worse symptoms.
Dr Mairi Stark, Lead for the Paediatric Acute Receiving Unit at Edinburgh’s Royal Hospital for Children and Young People and Scotland Officer for the RCPCH, said Scotland must vaccinate young adults “as quickly as possible”, to protect them from the virus.
“Quite a lot of young people, in their 20s and 30s, are getting really quite sick with Covid,” she said. Covid hospital admissions may yet rise as infections during Euro 2020 may take some time to filter through to hospital cases, she said.
Dr Stark warned that a “much more worrying” wave of other respiratory viruses may soon be seen in paediatric wards.
Dr Stark is already seeing parainfluenza, rhinovirus and bocavirus affecting children, and she expects a rise in RSV as schools return.
Parainflueza, which can cause croup, is “much more likely” to require hospitalisation or intensive care in children than Covid, Dr Stark said.
She said: “The question is what's going to happen at the end of August and September, and I think the viruses that we’re really going to be hit with, and the difficulties we’re going to have in paediatrics are not going to be Covid, they’re going to be all these other viruses.”
She added: “Flu didn’t really happen last year, and the children that would have got it last year will be coming across these viruses for the first time this year when they are a little bit older, so there will be all this year’s babies and all last year's babies, so a lot more children that have never come across all these viruses suddenly getting them all at once. That’s what’s worrying us in paediatrics… much more than Covid infections.”
Dr Stark called for measures such as mask-wearing and hand-washing to be encouraged after level 0.
“If you’re Covid-negative and you're wearing a mask, you're reducing the spread of all the other viruses, which are affecting more children,” she said.
"So mask wearing is a sensible precaution. If the SNP government wanted to continue that, that is more cautious and seems more sensible.”
Health boards around the country continue to report services struggling to cope with increased demand, and NHS Tayside said last week it was seeing young people both in hospital and intensive care.
Since June the health board has opened three extra Covid wards at Ninewells hospital in Dundee, where case rates have been highest in the country.
Patients are from “all age ranges”, including young people, NHS Tayside said.
Health boards in the north of Scotland have said they are under particular strain, and Gordon Jamieson, chief executive of NHS Western Isles, appealed to holidaymakers to take a lateral flow Covid test before travelling.
NHS Grampian is still under “huge pressure”, and while the situation is “slowly improving” in Tayside, the health board said it remains busy. Judith Park, Director of Acute Services at NHS Lanarkshire, said A&E in particular continues to be “extremely busy”.
NHS Highland said it is still experiencing high levels of demand, though Raigmore hospital, which was declared at capacity or “code black”, last week, is no longer at this level.
High pressure on NHS services is a result not just of Covid, but also of staff self-isolating due to contact with positive cases, and non-Covid illnesses.
The Scottish Government said it is “closely monitoring” the rise in parainfluenza cases.
“We recognise the additional pressure NHS staff are facing as they work tirelessly to respond to the pandemic whilst continuing to provide vital treatment and safe patient care. We are in daily contact with boards facing the greatest challenges and are monitoring the situation closely,” a spokesperson said.
“We are aware of an increase in parainfluenza being one of the reasons for high levels of activity in hospitals just now and we will continue to monitor the situation.
“We are acutely aware that hospitals are facing significant challenges due to a rise in non-Covid attendances and that some health boards are taking necessary measures to protect urgent and emergency care capacity.”
The government is working closely with Public Health Scotland on surveillance of non-Covid viruses, they said.