Thread by @apsmunro

Something I think we’ve been very bad at separating when trying to help people understand risk during the pandemic, especially for kids, is:

1. Risk of getting covid
2. Risk of being seriously ill IF you get covid

When we talk about risk, these things are very different

1/

The first is a product of:

-Prevalence (how many people are infected)
-Exposure (where are you that’s likely to get you infected)
-Variant (per exposure, more by Delta than others)
-Immunity (best by vax, or else infection)

These things change over time, so risk does too

2/

The latter is really a product of:

-Age (risk increases exponentially)
-Comorbidities (e.g. for children, neurodisability or cardiac diseases)
-Immunity

It is not clear whether variants significantly impact this risk - they may somewhat, but it is very uncertain

3/

Importantly, the risk of getting sick once infected does not change much over time, unless you get infected or vaccinated

(although over many years your risk does increase)

This is also true for children

4/

Children’s risk of become unwell if infected is *significantly* lower than adults, and in absolute terms is comparable to their risk from other respiratory viruses

They are all slightly different, but this is broadly true (e.g. IFR ~0.001 for both flu and covid)

5/

What can change is children’s risk of getting infected in the first place

If lots of people in the community are infected with Delta and they are exposed to lots of people, their risk of getting infected increases

This will result in more people being infected overall

6/

This can make it difficult to assess risk when, for example, you hear of more children being admitted to hospital etc

So far, this is usually due to an increased risk of getting infected, but not an increased risk of getting very unwell IF infected

7/

In addition, there are differences to assessing risks at the individual and population level

How worried would we be about one child with covid? Not very worried

How worried would we be about 5 million children with covid? A lot more worried, as some will be very unwell

8/

I think in general the medical/scientific community haven’t been good enough at delineating what type of risks we’re talking about, and how they apply to policy making vs individual risk assessment

I’ll try to summarise…

9/

Risks of a child catching covid are dependent on circumstances (as above)

Risks to an individual child who catches covid are low (like other resp viruses)

Risks of millions of children all catching covid at once are much higher, as even rare bad outcomes happen more often

10/