Scotland has been engulfed in a wave of coronavirus infections this summer, which has seen it topping the World Health Organisation’s Covid ‘leaderboard’ for Europe.
In the week to 3 September, the Office for National Statistics estimated one in every 45 people in the country had Covid, compared to one in 70 in England, one in 65 in Wales and one in 60 in Northern Ireland.
The situation has been frequently blamed on children returning to school, which they did much earlier than in the other three UK nations.
But does this explanation hold up to scrutiny – and does it mean cases are about to surge in the rest of the UK, too?
NationalWorld has analysed data from the UK Government Covid dashboard, to try to get to the bottom of Scotland’s rampant spread of infection.
What happened to cases when children went back to school?
Scotland experienced a very rapid increase in cases in the weeks after children went back to the classroom, as the graph below shows.
The lines on the graph track the percentage change in cases since the first day schools returned in each nation, compared to the number there were on the last day of the holidays, which is labelled Day 0.
Children in one part of Scotland went back to school on 11 August, making 10 August its Day 0.
In Northern Ireland, Wales and England, kids started going back on 1 September – making 31 August Day 0. The return was staggered in England, Wales and Scotland depending on what council area children live in.
The number of cases rose for 27 consecutive days across Scotland after schools started to return.
During the seven days to Day 1 there were 3.8% more cases than during the seven days to Day 0. On Day 2, there were 6.9% more, on Day 3 there were 12.8% more, and so on.
By the peak on Day 27, the number of cases was 408% higher than on Day 0.
So far, cases in England, Wales and Northern Ireland have not increased as dramatically.
The number of positive cases did increase in England and Wales for the first six days after the return to school, before beginning to decline.
In Northern Ireland, cases fell until Day 3, and have climbed each day since.
Does this tell the whole story?
The short answer is no.
All the data is based on the date tests were taken. That means any impact from schools returning should take a little while to show up in the data, to give children enough time to mix with one another, spread the virus, and then test positive – which may take a few days after exposure.
Data for the most recent five days is not provided, to give all tests the chance to be returned and processed before the figures are released.
When we zoom out to look at Covid cases throughout the whole of August it becomes clear that Scotland was experiencing an increase before any schools opened their doors.
The rate of cases per 100,000 people had been increasing gradually since 2 August.
However, it did pick up speed around 14 August, just after the first schools returned – but also after the country had left Level 0 on 9 August, removing the majority of restrictions and limits on social gatherings.
England on the other hand had been seeing a very steady decline in case numbers before kids went back to school.
Cases in Wales had been on the increase, rising more steeply than in Scotland. On the day before Scotland’s first schools opened, the seven-day sum of cases was 13.4% higher than it had been a week earlier. In Wales, that figure was 15.9%.
In Northern Ireland there had been a fairly marked decline since 23 August.
This may explain why cases have not yet risen as steeply in Northern Ireland or England in the days following the return to school – and time will tell whether they begin to catch up with Scotland on our first chart.
Which age groups were catching Covid?
Public Health Scotland publishes data on coronavirus cases by age group.
As the below chart shows, there were sharp increases in the number of cases among 25 to 44-year-olds, 20 to 24-year-olds and 15 to 19-year-olds before there were among under-15s.
The numbers have not been scaled to the size of the population in each age group – but that does not matter when we are looking at which age groups have been driving the increase in the overall number of cases.
The gradual increase in cases among under 15s picked up more speed from 22 August – Day 12 after schools started to return – jumping by 13% on the week before.
The steep increase among this age group continued right throughout August and into September, even when it had tapered off among other age groups.
This suggests that Covid was first being spread by people in their teens, 20s and 30s mixing more after Scotland’s so-called Freedom Day - the lifting of restrictions on August 9.
This was closely followed by classrooms reopening, which saw infections run rampant through the school-age population.
In England, on the other hand, its Freedom Day had less of an impact because cases had already spiked during the Euro 2020 tournament.
The gap between Freedom Day and schools reopening in England was also far wider, so they had less of a knock-on effect.
So was the lifting of restrictions to blame?
It’s a complicated picture, as the behaviour of the public doesn’t always tally with changes in official restriction levels.
Data gathered by Google through people’s phones shows where they are spending their time, compared with life before the pandemic.
People in Scotland's biggest cities didn't wait for Freedom Day to start leaving the house more often, data from Google suggests.
The pattern is broadly in line with the rest of the UK.
But this date saw the end of the legal requirement for social distancing and allowed bigger social gatherings, perhaps allowing the virus to spread more quickly.
Is Scotland testing more people?
The more tests taken, the more likely it is that asymptomatic cases that may otherwise have gone undetected are found.
That can mean countries that do more testing can appear to have more widespread infection, if you look at case numbers alone.
Looking at the positivity rate – the proportion of tests which come back positive – can be a fairer way to compare Covid rates in different areas.
About one-in-nine tests in Scotland are now coming back positive, compared to one-in-12 in England.
Scotland’s positivity rate overtook England’s in mid-August, shortly after Scottish restrictions were lifted.
The World Health Organization said last year that Covid could be considered under control when the positivity rate stays lower than 5% for a two-week period. Neither country currently meets that threshold.
What are the experts saying?
The Scottish spike in Covid infections first began in certain areas such as Dumfries and Galloway, according to Scotland’s Chief Medical Officer Gregor Smith.
Speaking at a press briefing at the end of August, he said there was “no one single reason or driver” behind the rise.
But he said they “appear to be in a catch-up phase just now with the rest of the UK”, with England having lifted restrictions earlier.
First minister Nicola Sturgeon said the country was seeing the impact of the lifting of restrictions on August 9 followed by the return of schools.
We want to hear from you: let us know what you think about this story and be part of the debate in our comments section below
A message from the editor:
Thank you for reading. NationalWorld is a new national news brand, produced by a team of journalists, editors, video producers and designers who live and work across the UK. Find out more about who’s who in the team, and our editorial values. We want to start a community among our readers, so please follow us on Facebook, Twitter and Instagram, and keep the conversation going. You can also sign up to our newsletters and get a curated selection of our best reads to your inbox every day.