Important Issue for Immunity Credentials

As was discussed briefly in the call today, if we are going to talk about
#Covid19 technology solutions, we must partner with health &
epidemiological experts to do it right.

For instance, it has been proposed that we support some kind of digital
immunity certificate. Even if we ignore its possible human-rights & privacy
risks, it can have still have risky public health care choices:

https://unherd.com/2020/04/how-far-away-are-immunity-passports/

“If you issue immunity passports on this basis, *barely a third *of the
people you give them to will actually be immune. “There’s nothing peculiar
about this statistically,” Kevin McConway, an emeritus professor of
statistics at the Open University, told me. “It’s just Bayes’ theorem
<https://en.wikipedia.org/wiki/Bayes%27_theorem>.” The likelihood of you
having had Covid-19, if you’ve had a positive test, depends not just on the
accuracy of the test but on the prevalence in the population you’re looking
at.
…
In the end, that’s going to be a horribly cold-blooded calculation. If you
let people out when they’re 90% likely to be immune, that means one person
in 10 is going to be at risk of getting and spreading the disease. Is that
risk a price worth paying for reducing the real costs (economic, social,
physical, mental) of isolation? I don’t know and I’m glad I don’t have to
work it out. But someone has to. And they’ll have to start by getting a
reasonably effective test, and testing hundreds of thousands of people, to
see how many of us have had it.”

— Christopher Allen