Tuesday 25 August 2020

A Safe Return to Schools? What does the Public Health England survey really show?

With the new term rapidly approaching in England, a phoney debate is being created suggesting that school safety campaigners don’t recognise the importance of children being in school. That’s not a debate. The real issue, however, is how that can be done safely.

Parents and school staff are being bombarded with an official narrative that schools will be safe to open with all children present in September. However, those claims are being based on questionable evidence.

Having read the actual content of the latest much-publicised schools survey from Public Health England I would go further and suggest that their claims are actually contradicted by their own facts. 

In my view, the PHE Report actually shows that:
  • Any conclusions reached from the PHE survey can only be based on the environment in school settings at that time – i.e. small class and bubble sizes and with most pupils still learning from home.
  • The survey only concludes that school transmission risks can be low when class sizes and local infection rates are low too. The data presented suggests that there could be significantly higher numbers of outbreaks if schools reopen without these conditions being in place.
  • The Report’s authors make clear its findings should not be applied to secondary schools and accepts that the risk of transmission is higher amongst older children.
  • In the thirty identified outbreaks, viral transmission IS clearly recorded as taking place within these (largely Primary and Early Years) educational settings.
  • While the survey suggests transmission from staff is more likely than transmission from children, in over a quarter of outbreaks (8/30), children are identified as being the source of the infection within the school.
  • The survey results confirm parent and staff concerns that staff can transmit the virus to pupils - and then back to their families – but also shows that staff can also be infected, even by young children, too.
  • The Report concludes that “most children were asymptomatic and only identified as part of contact tracing after their parent developed COVID-19, highlighting the importance of access to rapid testing, reporting and contact tracing for individuals to protect the wider community”.
  • The Report notes that 90% of schools closed the entire bubble when there was a single case reported and that 43% closed the entire school when there was an outbreak of more than one confirmed case.

Public Health England’s Report – a survey from educational settings in June & July 2020

It’s worth pointing out that the PHE Report, SARS-CoV-2 infection and transmission in educational settings: cross-sectional analysis of clusters and outbreaks in England, does not include medical research about the mechanisms of viral transmission. It is simply a survey of the infections and outbreaks reported in school settings in England in June and July 2020.

However, as the full Report notes, school settings were operating far from normally at that time: “Re-opening of educational settings was partial (nursery, reception, year 1 and year 6 in primary schools, and years 10 and 12 in secondary schools), not mandatory and the decision to re-open schools was met with mixed responses from educational staff and parents. Consequently, not all schools re-opened and not all parents sent eligible children to school during the remainder of summer term (June to mid-July 2020)

The Report itself acknowledges “important limitations when considering the generalisability of our findings. Educational settings opened after national lockdown when SARS-CoV-2 incidence was low and only in regions with low community transmission. Settings that opened had stringent social distancing and infection control measures in please and, in addition to school attendance not being mandatory, there were strict protocols for class and bubble sizes, which may not be achievable when schools opening fully in the next academic year (and indeed, updated schools guidance now recognises that bubble size may need to be increased from September to ensure that a full range of activities is feasible). Only 1.6 million of the 8.9 million students nationally attended any educational setting during the summer mini-term”.
  • Any conclusions reached from the PHE survey can only be based on the environment in school settings at that time – i.e. small class and bubble sizes and with most pupils still learning from home.
Are the chances of transmission in primary schools low? Our survey says: That depends! … on keeping class sizes and ‘bubbles’ small and taking particular care where local infection rates are high 

The PHE survey is being reported as evidence that the risk of viral transmission is low – as only thirty outbreaks were recorded in June and July 2020. However, as stated above, that was based on the environment in school settings at that time – i.e. small class and bubble sizes and with most pupils still learning from home. That’s exactly what ISN’T being planned for September.

The risks of transmission, as has been indicated by reports of outbreaks in schools globally, will inevitably increase if classes reopen at their full size, secondary schools operate bubble sizes of whole year groups and all pupils are on the school site at once – as the DfE intends to be the case as things stand.

This will be true in all schools but particularly the case in areas where there are higher infection rates. As the Report uncontroversially notes “we found a strong correlation between community SARS-CoV-2 incidence and COVID-19 outbreaks in educational settings. This is not surprising since increased community transmission provides more opportunities for virus introduction into educational settings”.

The data provided in the Report’s additional tables illustrates that correlation – but raises an obvious concern as to what the rate of outbreak might be in areas where the case incidence is higher (and there are many such towns and cities already) and without the ability to socially distance through smaller classes:



  • The survey only concludes that school transmission risks can be low when class sizes and local infection rates are low too. The data presented suggests that there could be significantly higher numbers of outbreaks if schools reopen without these conditions being in place.

What about secondary schools where medical research suggests that students may transmit the virus similarly to adults? Our survey says: Nothing, most secondary schools were only open to a few students

The Report is straightforwardly honest about drawing conclusions from its data about secondary schools: “Very few secondary schools opened (and those that did, did so with small class sizes) during the summer mini-term and our results, therefore, are not likely to be generalisable to secondary schools, especially since the risk of infection, disease and transmission is likely to be higher in older than younger children”.

  • The Report’s authors make clear its findings should not be applied to secondary schools and accepts that the risk of transmission is higher amongst older children.

Educational settings don’t spread the virus? Our survey says: Yes, they do! 

The survey notes that conclusions about transmission in settings where there were just single confirmed cases cannot be made because “the source of infection was not systematically collected”. But it confirms that there were thirty ‘outbreaks’ (defined as “2 or more epidemiologically linked cases, where sequential cases were diagnosed within a 14-day period”).

18 of these 30 recorded outbreaks were in Primary Schools, 7 in Early Years and 3 in SEND schools. Just 2 were recorded in secondary schools but, as stated above, most secondary classes were not in school at this time.

· In the thirty identified outbreaks, viral transmission IS clearly recorded as taking place within these (largely Primary and Early Years) educational settings.

Children don’t transmit the virus? Our survey says: Yes, they do! 

As is to be expected given global research about transmission from the youngest children, the survey found that “staff had higher rates of individual SARS-CoV-2 infection and outbreaks than students, albeit with wide confidence intervals”. However, politicians and journalists have chosen to focus on just one particular sentence in the Report that suggested that “staff members need to be more vigilant for exposure outside the school setting to protect themselves, their families and the educational setting”.

Many staff would, of course, contend that they are already being highly vigilant but that they cannot be held to blame for the failure by Government to reduce the risks of infection, both inside and outside schools. However, the Report clearly records that it isn’t only adults that can transmit the virus in school settings.

The survey states that “the probable transmission direction for the 30 confirmed outbreaks was: staff-to-staff (n=15), staff-to-student (n=7), student-to-staff (n=6) and student-to-student (n=2)”.

  • While the survey suggests transmission from staff is more likely than transmission from children, in over a quarter of outbreaks (8/30), children are identified as being the source of the infection within the school.

Staff can only transmit the virus to other staff? Our survey says: No, that's not the case! 

Again, the Report in full records that “of the 30 student cases involved in an outbreak, the potential source of infection in 27 children included a household contact (n=8), a school staff member (n=17) and another student (n=2).”

And, “of 91 staff members involved in an outbreak, where a potential source of infection could be identified, 9 acquired the infection from a household contact and were the likely index case in the outbreak and 52 likely acquired the infection in the educational setting from another staff member (n=46) or another child (n=6).

  • The survey results confirm parent and staff concerns that staff can transmit the virus to pupils - and then back to their families – but also shows that staff can also be infected, even by young children, too.

Did testing and tracing help identify infectious children? Our survey says: Yes.

Schools are being instructed to return to full opening while there are still considerable questions over the reliability off the test-and-trace systems in place, let alone making provision for the regular onsite testing of staff, so as to screen them for possible infection.

Confirming the evidence of child transmission, the report states that “Seven primary school outbreaks involved staff and students. In this small sample of outbreaks the student was most likely the index case in 6 outbreaks” but also adds that “In 5 outbreaks, the child (index case) was identified through ‘test and trace’; i.e. testing of the whole household when parents (healthcare workers in 3 cases) had tested positive for SARS-CoV-2. Seven staff members in contact with the index cases (3 tested because they became symptomatic) subsequently tested positive for SARS-CoV-2”.

  • The Report concludes that “most children were asymptomatic and only identified as part of contact tracing after their parent developed COVID-19, highlighting the importance of access to rapid testing, reporting and contact tracing for individuals to protect the wider community”.

Did schools close whole bubbles if there was just one case? - Our survey says: Yes, most have done so, some have closed whole schools. 

The Report notes that where there were only single confirmed cases, “Among 43/48 (90%) cases with available information, the case and contact bubble were excluded from 39 educational settings while four educational settings decided to close entirely because of a perceived risk of onward transmission, although this was contrary to national recommendations. For the remaining five cases (3 staff, 2 children) only the confirmed cases were isolated because they had remained outside the educational setting throughout their infectious period ”. 

In the 30 schools with outbreaks of more than one confirmed case “affected contact bubbles were excluded from school in all 30 outbreaks and 13 also decided to close either on an interim basis (to allow for deep cleaning or for exclusion periods to elapse) or for the rest of the term”.

  • The Report notes that 90% of schools closed the entire bubble when there was a single case reported and that 43% closed the entire school when there was an outbreak of more than one confirmed case.
Martin Powell-Davies, August 25 2020

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