Thread by @WilsonKM2

Quick thread on vaccines, outbreaks, and why *who* is vaccinated as much as how many (although both are very important)

There's a pre-print out that gives estimates (based on sero-prevalence) of the probability of needing to go to the hospital or dying if infected with SARS-CoV-2 for a series of age brackets: medrxiv.org/content/10.110…

If you know a population's age structure, you can somewhat estimate what an outbreak of a given number of infections will look like in terms of number of hospitalizations and deaths.

And if you know vaccine coverage, you can update those estimates for those effects, too.

So, just a quick demo of what an outbreak in Nova Scotia might look like in the coming months now that vaccines have been widely distributed.

Here's the simulated outbreak.

"That curve looks familiar!"

Yep, it's the Apri-May outbreak transported forward in time.

How many hospitalizations and deaths would we expect for varying levels of vaccination?

For each outcome, I've simulated 0% vaccine coverage, 50% and 80% total population coverage (but given randomly), current coverage by age group, and 100% eligible coverage.

Here are hospitalizations.

And here's the same for deaths.

The risk of serious disease increases exponentially with age.

NS has ~100% coverage over age 70, and not far off for the 60+ crowd as a whole. The result is that in theory the population should be well protected from surges of hospitalizations/deaths.

But that's the community risk level, what about individual risks?

Basically contingent on vaccination and age.

"I'm not 60+, I'm zero-risk!"

Err, no. I think the public sometimes has a shaky sense of the risks associated with being infected with SARS-CoV-2.

So let's put the infection risk in context.

Whenever someone jumps out of a plane to go skydiving, there's a 1/220,301 chance of them dying.

How does this stack up to being infected?

Per the estimates from the pre-print:

If you're in your 20's, infection almost 15x more likely to end in death than skydiving (925x more likely to end up in hospital than die on a given jump).

If you're in your 50's, you're nearly 9000 times more likely to land in the hospital vs die from a given sky diving jump.

To get the same mortality risk as being infected, you'd have to go skydiving 820 times.

So, maybe just go get vaccinated instead.

Sidenote: you're probably wondering about the wave of hospitalizations and deaths in parts of the US.

I think parts of this is down to the vaccine roll-out in some states. Much lower overall coverage and substantially lower coverage for older age groups, hence bad outcomes.

Anyways, that's it for the short thread.