16 July More on children

The guidance of this discussion is from the first attachment, a recent commentary in Science (first attachment)  

1. Conclusion from a (previous) review https://dontforgetthebubbles.com/the-missing-link-children-and-transmission-of-sars-cov-2/ 

• Children appear significantly less likely to acquire COVID-19 than adults when exposed
• There is reasonable evidence that there are significantly fewer children infected in the community than adults
• Children are rarely the index case in a household cluster in the literature to date
• It is not clear how likely an infected child is to pass on the infection compared to an infected adult, but there is no evidence that they are any more infectious

See the table in  2nd attachment for a summary on attack rate

2. Science COVID reporting (2nd attachment): Emerging conclusions from schools closing and reopening around the globe:

• Data … suggest a combination of keeping student groups small and requiring masks and some social distancing helps keep schools and communities safe, and that younger children rarely spread the virus to one another or bring it home. 
• …. the benefits of attending school seem to outweigh the risks—at least where community infection rates are low and officials are standing by to identify and isolate cases and close contacts.

3. Two related serological  studies (3rd and 4rd attach) from a “hotspot” in Northern France (Crépy-en Valois) by Fontanet et al highlight the difference between primary school children and adolescent in high school. 

This investigation identified an epidemic around a local high school with two teachers having symptoms consistent with COVID-19 as early as on 2 February 2020.  ….

A preliminary rapid investigation among symptomatic adults and pupils at the high school on 5-6 March 2020 revealed that 11/66 (16.7%) adults and 2/24 (8.3%) pupils had acute infection, as determined by a positive RT-PCR test result. The decision was made to further examine by serological testing (antibodies as evidence of present or past infection)  the extent of infection among pupils, their parents and relatives, teaching staff and non-teaching staff of 1) the high school where the two teachers worked and 2) the primary schools in the same city

• • In the high school SARS-Cov-2 prevalence was  38.3% (pupils) 43.4% (teachers), and 59.3% (school staff). In parents and siblings it was much lower  (11.4% and 10.2%, respectively.  In the community (blood donors), it was only 3 %.
  • In the primary schools, the percentages were  8.8 % (pupils), 7.1% (teachers), 3.6% non-teaching staff) 11.9% (parents) and 11.8% (relatives). In young children, SARS-CoV-2 infection was largely mild or asymptomatic. Despite three introductions of the virus into three primary schools, there appears to have been no further transmission of the virus to other pupils or teaching and non-teaching staff of the schools. In families of infected pupils, the prevalence of antibodies was rather high, suggesting intrafamilial clustering of infections.

Fontanet concludes that pattern suggests (1) high schoolers were catching the virus at school, (2) the younger pupils caught it from family members and not their classmates

4. Clearly, however, not all data are consistent:
   • Consistent with Crépy-en-Valois are the following data: an outbreak at a New Zealand high school before that country’s shutdown infected 96 people, including students, teachers, staff, and parents. In contrast, a neighboring elementary school saw few cases.  Similarly in high school in Jerusalem, where 153 students and 25 staff were infected.
   • In contrast to Crépy: in Israel and Canada, two cases where many primary school kids were infected, with limited infection rates in staff.
   • In Texas with a very strong epidemic:  441 children positive in daycare centers (together with 894 staff) in 883 facilities….
   • The situation in Florida is also dramatic: 1/3 of the children under 18 who were tested, turned out positive and as you can see in the Tables 5th attachment) , there is a high number of young children.  The overall rate of hospitalization is still low: 1.25 % and death rate only 0.02 %. 
   •  
5. Should children keep distance?  There is no systematic research.  In practice, there have been several models of clustering and distancing in various countries, but the tendency is to  loosen the restrictions.

6. Should children/students wear nose/mouth caps (face masks)?  Similarly to distancing, practices vary a lot: in the Far East it is still strict, in the West it is fading and in the South, it is not affordable…. In view of the observed differences in susceptibility and transmission between primary and secondary schools, it seems reasonable to request it rather in secondary school.  The case of the outbreak in a gymnasium in Jerusalem, two weeks after leaving the face masks off, is suggestive….

7. School closures after positive case?  Clearly no consensus.  Longitudinal studies in UK and Germany underway to address the question how  many children and staff will be infected (PCR and antibodies). The UK protocol has been added (6th attachment) .

8. Multisystem inflammatory disease in children: is broader than Kawasaki syndrome.  See 7th attachment.

 -   Cardiovascular involvement is common, almost half receiving vasopressor or vasoactive support and 1 in 12 having coronary-artery aneurysms.

- Also gastro-intestinal, mucocutaneous and hematological complications are very common.

- 40 % had citeria for Kawasaki syndrome.

- 20% received invasive mechanical ventilator support.

- 2 % died.

Best wishes,

Guido