This is not a good answer to what is a very reasonable question.
The key argument is that we can swap high contacts in adults, for very low contacts in adults and high contacts in kids in school.
That’s not true.
Why?
1/
The key argument is that we can swap high contacts in adults, for very low contacts in adults and high contacts in kids in school.
That’s not true.
Why?
1/
What’s a contact?
It’s spending enough time close enough to someone, and often enough, for effective viral transfer. It’s a (probably) non-linear function of distance, time and *frequency*.
2/
It’s spending enough time close enough to someone, and often enough, for effective viral transfer. It’s a (probably) non-linear function of distance, time and *frequency*.
2/
For household contacts the average risk of infection is fairly high, at about 15% to 30%.
It’s much worse in very crowded houses.
3/
It’s much worse in very crowded houses.
3/
Masks almost definitely reduce the risk of an infected person spreading the virus, but probably don’t protect you much from an unmasked person.
This is why teachers and students *must* wear masks.
4/
This is why teachers and students *must* wear masks.
4/
Distance means over 1 metre from the face, and preferably over 2 m.
It looks like this virus mostly spreads by droplets, which is good, though aerosol spread (risky over much longer distances) is a factor too.
Irish schools will struggle to achieve one metre.
5/
It looks like this virus mostly spreads by droplets, which is good, though aerosol spread (risky over much longer distances) is a factor too.
Irish schools will struggle to achieve one metre.
5/
The number of contacts does matter, but, as the household data tell us, the duration and intensity of contacts matters too, and probably matters more.
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6/
Typical ‘superspreader’ events seem to last an hour or more, so we see outbreaks in concerts, parties, choir rehearsals, or because of long journeys, working shifts in factories, and the like.
7/
7/
You can, of course, be unlucky, and pick it up while standing in a lift for two minutes with someone else, but that seems to be unusual.
8/
8/
School contacts are prolonged, and very close. It’s likely that one infected person in a classroom for one day could infect 5% to 20% of the rest of the class. Over several days, attack rates could be 50%, as in several outbreaks in schools in Israel and Melbourne.
9/
9/
It’s wrong to equate these prolonged close contacts to the typical brief contacts that make up the bulk of adult non-household contacts.
A contact is not the same as any other contact.
In economic terms contacts are not exchangeable.
10/
A contact is not the same as any other contact.
In economic terms contacts are not exchangeable.
10/
Schools can and will be made as safe as possible, but that’s still not 100% safe.
The *only way* to keep schools very safe is to sharply reduce the rate of community transmission in Ireland.
There’s no plan to do this, and this new guidance is not such a plan.
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The *only way* to keep schools very safe is to sharply reduce the rate of community transmission in Ireland.
There’s no plan to do this, and this new guidance is not such a plan.
End/
