Will school re-opening lead to increased #SARSCoV2 #COVID19 transmission?
New article examines evidence children transmit virus during school
Mostly anecdotal stories; few actual analyses.
1 idea for how we can do better; more needed!
Thread.
sciencemag.org/news/2020/07/s…
New article examines evidence children transmit virus during school
Mostly anecdotal stories; few actual analyses.
1 idea for how we can do better; more needed!
Thread.
sciencemag.org/news/2020/07/s…
Background:
In-person schools are crucial for learning (especially for young children) but carry obvious risks due to crowded settings, and risky behavior that is hard to control (in both young children at school and older kids in&out of school).
In-person schools are crucial for learning (especially for young children) but carry obvious risks due to crowded settings, and risky behavior that is hard to control (in both young children at school and older kids in&out of school).
Studies in children *sometimes* indicate lower & sometimes equal infection rates in kids by PCR or serology (; )
But PCR studies may be biased by lack of symptoms resulting in later testing & missing infection
But PCR studies may be biased by lack of symptoms resulting in later testing & missing infection
Lower infection prev has been interpreted as them being less susceptible but could be due to behavior ("shielding" by parents).
Viral load data still very limited but suggest similar loads and definitely live virus present:
virologie-ccm.charite.de/fileadmin/user…
wwwnc.cdc.gov/eid/article/26…
Viral load data still very limited but suggest similar loads and definitely live virus present:
virologie-ccm.charite.de/fileadmin/user…
wwwnc.cdc.gov/eid/article/26…
So children definitely CAN be infected (maybe less susc. maybe equal but def not refractory to infection), and MAY be equally infectious (and certainly can transmit). So question is, given this, will schools, where close contact rates are high, increase transmission in community?
Recall that risk is not so much to children in which severe illness is very rare, but transmission that leads to infection of older individuals where risk of severe illness and death much higher.
Article includes many stories about schools either re-opening or being open & having/not having outbreaks. Some outbreaks occurred!
Missing in discussion of each example was background level of transmission. A gathering (e.g. school) can avoid outbreaks if few are infected.
Missing in discussion of each example was background level of transmission. A gathering (e.g. school) can avoid outbreaks if few are infected.
Remember that for COVID19 most cases do NOT lead to infection; only a few do, but lead to many cases. Thus detection of a couple infections & little or no spread not definitive. Need repeated introductions & outcome.
doi.org/10.1016/S1473-…
doi.org/10.1016/S1473-…
Thus, we already know transmission CAN happen in schools and teachers CAN get infected and even die. But we don't know if transmission in schools will be so high risk that costs outweigh clear benefits, especially if community transmission is moderate.
(sciencemag.org/news/2020/05/h…)
(sciencemag.org/news/2020/05/h…)
(Note that an obvious and much desired strategy is to reduce transmission in community so schools are safer; question is if we can't achieve this, do we open schools anyway?)
To properly assess relative transmission intensity b/w schools and groups of adults we need to compare transmission in those two groups w/ known # of introductions. Article mentions future study of students & teachers but no paired pops outside schools.
charite.de/en/service/pre…
charite.de/en/service/pre…
In addition, testing interval in Germany study - every 3 months by PCR and serology - is too infrequent to differentiate w/in school transmission from community transmission that leads to infection of students in their homes.
Idea: Study that frequently (weekly?) tested groups of 5-10yr, 11-18, 19-22 students at grade/high school & university/college in same communities could provide comparison of pops in which all rarely have symptoms (but fever may be lower in college - fig doi.org/10.1016/S1473-…)
Obviously big differences in types of interactions but all would have plenty of close contacts & few symptoms. Should older group of non-students be added?
Ideally, for study, in all settings one would observe several viral introductions and then measure how much spread occurred.
Ideally, for study, in all settings one would observe several viral introductions and then measure how much spread occurred.
Challenges:
-Might be hard to make prevention measures (masks, distancing) similar
-Might be hard to make public health response when virus detected similar
-Differences in behavior inside/outside school among ages might make comparison difficult to interpret
-Might be hard to make prevention measures (masks, distancing) similar
-Might be hard to make public health response when virus detected similar
-Differences in behavior inside/outside school among ages might make comparison difficult to interpret
Do others have ideas for study designs that would better answer this very important question?
Authors of article (sciencemag.org/news/2020/07/s…) seemed frustrated at mixed evidence but w/out careful comparative study I don't see how we'll resolve this.
Authors of article (sciencemag.org/news/2020/07/s…) seemed frustrated at mixed evidence but w/out careful comparative study I don't see how we'll resolve this.
Would love to hear study design ideas from
@DrZoeHyde @rozeggo @c_drosten @apsmunro
@nataliexdean @EpiEllie @aetiology @AdamJKucharski @CT_Bergstrom @mlipsitch @Caroline_OF_B @Steve_Bellan & others!
@DrZoeHyde @rozeggo @c_drosten @apsmunro
@nataliexdean @EpiEllie @aetiology @AdamJKucharski @CT_Bergstrom @mlipsitch @Caroline_OF_B @Steve_Bellan & others!
