- Hi, I'm Jonathan Zittrain.
I teach on law and computer science at Harvard University.
And I'm a director of the Berkman Klein Center
for Internet and Society.
And in this video, I just want to get some terms straight
around contact tracing.
The World Health Organization defines
contact tracing as identifying, assessing, and managing people
who've been exposed to a disease to prevent onward transmission.
I realize that word "managing" might sound a little ominous.
But really what it's talking about
is having people be in a position
to know that they are infected and could be contagious
even if they're not yet showing symptoms,
so they would naturally maybe self-isolate.
And if it turns out you've tested positive,
the ability to know that soon and to be
able to find out who you've been in touch with during the window
in which you might yourself have been contagious--
and once you do that, that contact tracing
allows those people that you've been
in touch with to themselves be notified that they could be
exposed and to let them quarantine so that they're not
further exposing others as they wait
to see whether, in fact, they've come down with the illness
that you might well have shared with them.
Contact tracing, in its traditional forms,
involves interviews.
And this also might be why you've
seen in the United States news of the standing
up of, according to what Johns Hopkins study,
up to 100,000 new workers who will be contact tracers working
for states, counties, and cities.
Their health departments doing these sorts of interviews.
Now is it necessary to do this?
You might be about to find out.
If you look at any of the plans for reopening the United States
in the spring of 2020, these plans all
contemplate testing, tracing, and quarantine as a key pillar.
And the White House plan for reopening has as one
of its three sets of core state preparedness responsibilities,
testing and tracing.
Now the traditional interviews that I was just mentioning,
they rely on imperfect human recollection
in order to figure out where somebody has been
and who they've been in touch with.
And those interviews also involve really specialized work
and handling sensitive data.
And right now, it's hard to scale up all of the contact
tracers we would need able to handle that data sensitively,
to figure out the right survey instruments,
and how to offer the kinds of services that they can.
And that's why we also now start hearing
about digital contact tracing, a subset of case management
tools.
Case management tools can be something as basic and boring
as the software that a contact tracing professional
might use to keep track of all the people their calling, what
those people are telling them, who needs to be called next,
where the follow-ups are.
And there are contracts out by many of the states
and municipalities engaging in contact tracing to have
that kind of software at hand.
But there is a second form of digital contact tracing
assistance tools that involve possibly
using your smartphone in some way
in order to be able to say the data that this phone is
gathering as you walk around in the world could really
help either by some lights, substitute for,
and by many others, simply be a helpful input to a complement
to the kind of interviewing that we expect to happen when
digital contact tracing happens.
And a big question definitional here is to what extent
will the data on that phone be used
as GPS or geolocation, absolute location data.
If the data on the phone can tell you
where you have been at various times during the day,
during the past few weeks, or something, that's
the kind of thing that would really help a contact tracer
help you jog your memory, oh, yeah.
I went to the store on Wednesday, not Thursday,
or oh, I remember I was on the highway at that time.
And so anybody I was near, no problem because I
was in the car.
I was inside.
I was outside.
These are all things that can affect
the transmission of COVID-19 as a disease,
and it might be material.
Now there's a catch.
Because a lot of the contact-tracing apps that
we've seen made available to people,
some of them seek to use geolocation data, others don't.
And one reason is because Apple and Google have come up
with a framework, a framework that they are wanting apps
to be able to tap into on Android phones or iPhones that
will use a neat clever trick to figure out
who has been near whom without needing to know where anybody
has been.
And the parlor trick, the rabbit in the hat
is more or less something called BLE, Bluetooth Low Energy.
And this is part of newer iPhones and Android phones
that has the phone able to send out
a small beacon, a kind of RSSI, or received signal strength
indicator, from one Bluetooth beacon to another
that can say, oh, yeah.
I've been within 6 feet or 12 feet
or something of another beacon, another phone,
for example, whether or not I know the person who
has that phone or whether or not our phones have
talked to one another.
And the idea is that apps could be written
to tap into that Bluetooth Low Energy
so that you would know when your phone has been near another,
or more important, your phone would know--
and should you test positive and be
able to certify as much to an app on your phone
with the assistance of the public health authority,
that phone would now be able to send a cascade of notifications
out to people meeting that certain threshold for thinking
that their phone has been near your phone
within a particular period of time.
Now the catch is that for privacy reasons,
Google and Apple's framework does not contemplate
the use of any location data.
So it'll tell you that you have been near another phone
and tell the owner of that phone without telling you
who it is that your phone has been their phone.
And they don't get told who you are either.
They then have a chance to call their health department
and say, I think I've been exposed.
But no other data other than that proximity
is used to do it.
And the database itself is basically
distributed among all the phones.
Now that's great from a privacy perspective.
It does tend to make for trouble if what
you want is the more fulsome data that a contact
tracer doing an interview would you
is to say, oh, I see you've been proximate to this other person,
but that's because you're in apartment building,
and they're on the floor above you or below you.
So that's no problem.
You're not sharing any air between you,
and that shouldn't count as a contact.
So these are some of the issues we'll
see as we look at different app makers looking
to make apps that can be helpful in tracing
or an exposure notification.
They're going to have to choose whether to use
the Apple-Google framework, which will only
do this kind of cool proximity, or if they want
to try to kind of freelance on their own
and make apps that might make use of location or other data
on the phone, thereby though precluding them
from using the special framework that Apple and Google have
come up with.
A lots of other issues too, ranging from battery life
on the technical side of things.
If your phone is trying to figure out
where you are all the time, that can lead to a lot of trouble
in just using the phone for its normal purposes.
And in the broader perspective, it
leads to some issues around opt in and voluntariness.
For these sorts of apps to work, to be linked to one another,
even if the people don't know who one another are,
it's going to be important for those apps to be installed
on a lot of phones.
And right now we're contemplating people
going and downloading the right app and doing that.
It might be that we need as many as 60% or 70%
of the population to be using these apps.
And not only that, but to have them installed and running
days or a week or two before they're
notified that they might be testing positive
or have themselves been exposed and then wanting
to use the data.
Figuring out these sorts of issues, distributed versus
centralized, databases, the privacy dimensions,
and trade-offs around what kind of data gets used
and how it gets shared and how labeled it is
and how these apps are or aren't meant
to integrate or able to be integrated
with the traditional interview-based
social-work-based contact tracing kinds of activities
that we see from the public health departments.
These will be the subjects of the next video.