Given the recent public statements by several govt advisors regarding opening of schools, here's a thread on evidence around COVID in children:
The govt (& UK scientific 'experts') have recently cited findings from the recent PHE study as suggesting school openings are safe 1/N
The govt (& UK scientific 'experts') have recently cited findings from the recent PHE study as suggesting school openings are safe 1/N
The study does not in fact show this at all. It essentially collates data on results from test & trace during the period when schools were opened in June - when only ~7% of students attended. There are several key limitations of this work:
1. Given the attendance was a fraction of normal attendance, we cannot possibly extrapolate what this will mean for when schools fully open from this study. 3/N
2. The study shows, as many of us have suspected - that even with the limited attendance the rate of infection within schools was highly dependent on background transmission within the region. 4/N
So, if the background transmission were to increase (as it is currently), the impact of school openings could be greater. This can actually be gleaned from a review of current evidence, where many studies in Europe, when transmission was low didn't show school outbreaks. 5/N
But we have seen clustered outbreaks in the US, and other regions with higher regional transmission. So, studies in a given setting, at a point in time cannot be extrapolated to other points in time. As local transmission increases, risk of school clusters emerging will increase.
3. Another important limitation of this, and many other studies that claim that 'children don't contribute to transmission' is in the way these studies define index cases. In the UK, testing, even in schools has been symptom based. This is an important limitation. Here's why:
As children are often asymptomatic, they are unlikely to be picked up as 'index cases' with symptom based testing. Just because a staff member with symptoms is identified as the 'index case', does not mean that the infection didn't start with an asymptomatic student.
A large study from S. Korea examining 59,073 contacts of 5,706 index cases actually suggested that the highest risk of transmission was from index cases who were school age (10-19 yrs). This really brings into question the notion that children do not play a role in transmission.
Virological studies have confirmed that symptomatic children of all ages have at least equivalent levels of virus compared with adults. While this does not necessarily translate to increased transmission, it suggests that we need to carefully assess this before we rule this out.
Even the ONS survey data shows that school age children are infected with a similar incidence as adults. They are less represented in symptom-based testing because many of them are asymptomatic. But we know that asymptomatic individuals can transmit. We just don't know how much.
Empirical evidence from many different regions suggests that school opening can lead to local clusters - even when school opening is limited. This has been borne out in the US, Scotland, S. Korea, and many other regions.
It's important to note that in most of these cases school openings were in a context of low background transmission, & continuing restrictions. We cannot predict the impact school openings will have against a background of fewer restrictions & possibly higher transmission.
Despite all the accruing evidence that suggests that children may play an important role in community transmission, the govt appears to have focused on a single study which is so limited by the context its been carried out in, that no clear inference can be made from it.
The govt has focused on the fact that children are less likely to be harmed by COVID. While current evidence supports this, we don't fully understand the long-term impact of the virus in children or in adults.
It took a while to understand that COVID could cause a severe but rare life-threatening syndrome in children - there is much we might still not understand. And even if the harm to children is limited, the impact on community transmission is key. Children don't live in isolation.
I want to be clear that I'm not against school openings in any way. I fully understand the detrimental impact of school closures on children, and on social inequities within communities. We need to open schools - safely.
The best way to do this safely is to deal with community transmission. If community transmission is low, we're unlikely to see superspreading events and clusters. To do this, we need to aggressively tackle the virus- with widespread mask use, comprehensive test, trace & isolate.
We're at a point where schools are due to open in a couple of weeks, and we're seeing rises in cases across most of England. This was preventable. The govt says its prioritising school openings, whilst allowing high community transmission through rapid easing of lockdown.
And lack of widespread mask use in crowded settings. And a test, trace, and isolate strategy that's far from effective. The govt hasn't created a safe environment for school openings, while stating that this is an absolute priority.
And have now twisted the evidence to misinform the public about the risks. None of this was inevitable. We could've planned for school openings by cautiously easing lockdown, while putting mitigatory measures in place. We did none of that.
