Those with long memories may recall that back in mid-March, when the UK government was still doggedly resisting a full lockdown, we were told that school closures were unnecessary because they would make little difference to corona-virus transmission rates. Yet in the past week there has been a chorus of concern about the risks of a second wave of Covid-19, even bigger than the first, as a result of schools fully reopening in September. Notably, one of the voices raising the alarm is Professor Neil Ferguson (interviewed on page 36) of Imperial College London – a former Sage adviser – whose modelling was so influential on policy those few short months ago.
In the early months of the pandemic, countries such as the UK – which were basing their policy responses on theoretical modelling rather than time-honoured public health practices – were having to feed those models with imperfect data. Schools are known to be important transmission engines during flu epidemics, but Covid-19 is very different from an influenza virus. The nearest comparator was thought to be the original severe acute respiratory syndrome (Sars), which hadn’t been significantly transmitted through schools. This assumption – that in terms of school transmission, Covid-19 would be more like Sars than influenza – has now been completely revised.
Sars invariably made patients extremely unwell, so there could be no doubt about what was wrong with them; and it did so rapidly, so there was no pre-symptomatic period during which individuals could spread the disease unwittingly. Covid-19, on the other hand, affects at least 80 per cent of people trivially, and starts viral shedding days before anyone realises they’ve contracted it, ensuring a plentiful pool of people unknowingly propagating the infection.
We also now have a clearer idea of how Covid-19 affects young people. The first major study to address this – involving 82 paediatric centres in 25 European countries, and published in the Lancet in late June – found that more than half with proven Covid-19 display standard cold symptoms. Only a quarter have a cough, and at least a third have no fever at all. This study involved only the sickest children, most of whom had been referred to hospital. The picture among paediatric cases in the wider community is even more nebulous.
This is a problem for the UK, where our case definition – and therefore eligibility to access testing – still rests on the presence of one of three hallmark symptoms: new continuous cough, fever, or loss of taste and smell. We are failing to detect most Covid cases in young people because they don’t look like they have it. I come across this regularly. Just this week I took a call from Kirsty, a seasoned mother of three boys, who had been gamely getting on with life despite one of them being really rather poorly with a “cold”. It was only a week later, when one of his siblings came down with an illness that looked a bit more like Covid-19, that she reconsidered.
Earlier in the summer, there was a flurry of studies purporting to show that children with Covid-19 weren’t very infectious. Were this the case, then transmission in schools wouldn’t matter terribly much. There could be some biological plausibility behind this belief. Children, exposed so frequently to “usual” respiratory infections, have immune systems primed to counter viral incursions, therefore Covid-19 may not get a chance to reproduce effectively in their airways and launch off to find new hosts. Yet every parent, teacher and GP in the land can attest to how readily children share every other viral infection they contract. It would be strange for Covid-19 to be such an outlier.
Those trial results may simply be artefacts arising from the way the studies were conducted – trying to work backwards from adult cases – as well as the fallibility of swab tests. Certainly, the outbreaks of Covid-19 now occurring around Europe appear to be driven by escalating case numbers in teenagers. My hunch is that Covid-19 will prove to be just like other respiratory viruses – eminently transmissible by the young. The rising numbers of teenage cases probably reflects the frustration and boredom that lockdown brought to their lives. Now, many – possibly most – are going well beyond what is officially permitted in terms of social interaction (perhaps, inspired by the example of their political leaders, they are choosing to exercise personal judgement in the interests of their own well-being).
Neil Ferguson now seems persuaded that teenagers are efficient Covid-19 transmitters, though he still believes that primary school children may be mysteriously different. I suspect that, unlike their more autonomous teenage brethren, these much younger children simply haven’t had the freedom yet to show us what they can do. That will come when they return to school.
What then is to become of our children? Are schools, colleges, universities going to have to shut down again within a few months as cases surge? Ultimately, this will be a question of what we prioritise as a society. The academics sounding the alarm all make the point that with a test and trace system that is actually fit for purpose (England’s is a long way off that) we could control case numbers by breaking enough chains of transmission. We would need even higher testing capacity, much more regional devolution and, crucially, a less prescriptive case definition that matches real-world experience of Covid-19.
The alternative is to counter rising transmission in educational environments by suppressing that being generated elsewhere. As events in Aberdeen have demonstrated, pubs also aid viral spread even when complying with social distancing measures. As a nation we may be forced to choose which we value more: nights out on the town, or our children’s education.