It’s five years since Covid-19 rampaged across the world, changing our lives immeasurably.
It was a tough time for schools, not just with the impact of lockdowns on teaching, but the subsequent upheaval of having to implement bubbles, social distancing and mask wearing.
However, over the past few years, new scientific evidence is emerging that suggests all of this effort had a key role in reducing infections - and may prove useful for dealing with future outbreaks.
1. A Dutch case study
A recent study from the Netherlands compared the impact of schools and households on Covid-19 transmission between June 2020 and October 2021.
“We focused on students transitioning from primary school to secondary school,” explains Javier Garcia-Bernardo, assistant professor at Utrecht University and researcher on the project.
“By looking at this specific group, we could distinguish whether infections occur primarily in the classroom, between classrooms at school, through social ties inherited from primary school, or through non-school interactions such as community transmission,” Garcia-Bernardo adds.
The researchers used polymerase chain reaction (PCR) test data to calculate the probability of both students in a pair testing positive for Covid in a 14-day period. At the time of testing, schools were using mitigation measures such as social distancing - and the effect of these is clear.
The researchers found the probability of infection was far lower (1.65 per cent) for those attending the same secondary school compared to the probability (22.6-23.2 per cent) for siblings and parent-child pairs living in the same household.
They also found a relatively high probability (4.7-7.9 per cent) of transmission even when family members lived in different households.
The results show that “family and household interactions are a crucial factor in spreading Covid-19”, Garcia-Bernardo says - more so than schools with Covid prevention measures in place.
2. A similar tale in London
Meanwhile, a study on the impact of Covid-19 transmission across eight schools in London between October 2020 and July 2021 found similar results.
In this study, researchers identified schools reporting new cases of infection. They tested students at these schools and their families, and sampled home and school environments.
At this time, schools were implementing “stringent precautionary measures” and some were using class bubbles, says Lucy Reeves from Imperial College London’s Department of Infectious Disease, a researcher for the study.
The team found that rates of transmission in schools were low: in 28 bubble contacts (representing 10 bubble classes), Covid was not detected at all, while across eight non-bubble classes, two per cent of students tested positive.
In contrast, transmission from infected pupils to household contacts was much higher, occurring in 17 per cent of cases.
It was a similar picture for environmental contamination: Covid traces were found in samples in 2 per cent of bubble classrooms, 2 per cent of non-bubble classrooms and 4 per cent of school toilets tested. Meanwhile, in households tested, Covid traces were identified in 24 per cent of bedrooms, 27 per cent of communal rooms and 11 per cent of bathrooms.
Air sampling showed a similar trend, with Covid found in 2 per cent of school air samples and 25 per cent of samples from homes.
Overall, Reeves says these findings show the work of schools was key to cutting transmissions: “Our findings suggest that the precautionary measures implemented by the schools we studied were effective in reducing transmission and minimising surface and air contamination.”
3. The same findings at national level
Despite the London study’s comparatively small scale, it had similar findings to another UK Covid paper that looked at a much higher number of schools.
This study, published in The Lancet in 2021, analysed Public Health England data from settings that were open in the summer half term of 2020, from 1 June to 17 July. That’s a median of 38,000 early years settings, 15,500 primary schools and 4,000 secondary schools.
The research team used the data to classify incidences of Covid as single cases, co-primary cases (where there were at least two within 48 hours) and outbreaks (where there were at least two linked cases, with sequential cases occurring in the same school within 14 days).
Overall, it followed the trend we have seen so far: that Covid-19 infections and outbreaks were uncommon in schools where infection control measures were in place.
Across all the settings, which had a median daily attendance of 928,000 total students, there were 113 single cases of Covid, nine co-primary cases and 55 outbreaks during the half term - in essence, very few.
Notably, though, the study found Covid cases among staff were more common than students. Per 100,000 people per day, they found 27 staff cases compared to 18 in early years children, 6 cases in primary pupils and 6.8 cases in secondary students.
And who was infecting whom? The research found staff-to-staff cases were most frequent, occurring in 26 outbreaks, compared to eight staff-to-student cases, 16 student-to-staff cases and five student-to-student cases.
This time, the findings point more explicitly to the impact of regional cases of Covid on school transmission: the risk of an in-school outbreak increased by 72 per cent for every five cases per 100,000 people in the community.
As such, the researchers say this strong association between local Covid-19 cases and cases in schools “emphasises the importance of controlling community transmission to protect educational settings”. And that you can do so without closing schools, if mitigations are used.
4. Mitigation measures help with flu outbreaks, too
Of course, we hope there won’t be another pandemic. But other viruses, such as cold and flu, are common. Could these findings help schools mitigate the spread of other diseases, too?
A Japanese study from 2021 suggests so. It looked at influenza outbreaks in 29 primary schools - accounting for 10,923 students - in Matsumoto, a city north-west of Tokyo, and found that they could not be supported by within-school transmission alone - but relied on new infections from households and communities.
The research team found that in a school with six year-groups and classes of 30, the risk of transmission was 1.8 per cent from a classmate of the same gender, 1.6 per cent from a classmate of a different gender, 0.12 per cent from a student in the same year and 0.036 per cent from a student elsewhere in the school. Meanwhile, the risk of community infection was 2 per cent.
Interestingly, and unlike the other studies detailed above, this one used data from 2014-15 - well before the introduction of Covid precautionary measures. However, other measures were in play that schools could learn from - even outside a Covid context.
For instance, mask wearing was already much more common in Japan than the UK, and the researchers found it was associated with both reduced susceptibility and infectiousness, suggesting English schools should encourage students to wear masks during a flu outbreak.
They also found that vaccines were associated with reduced susceptibility - further confirmation that the anti-vax movement is a worrying one.
Overall, these studies show the mitigation measures that schools worked so hard to implement really did help to minimise the spread of Covid in schools - and simple acts like mask wearing could work similarly well for containing flu and cold outbreaks, too.
Though, hopefully, the need for full-blown virus-prevention measures such as bubbles and social distancing that were so central to school’s lives five years ago, won’t be needed again.
For the latest education news and analysis delivered every weekday morning, sign up for the Tes Daily newsletter
