Dr Michelle Dickinson: Nanotechnologist on whether seeing an ill person can trigger your immune system

Have you ever instinctively taken a step back when someone sneezes near you on the bus? It turns out that your body may be doing more than just helping you avoid germs, it might be quietly powering up your immune system too. 

In a new study published this week in Nature Neuroscience, researchers found that even the sight of someone who looks contagious can kickstart a biological response in your body. 

In the study, virtual reality headsets were placed on 248 healthy participants who were shown videos of people who appeared either neutral, fearful, or visibly sick (with skin rashes or other infection-like cues). These virtual people slowly moved closer to the participants in the simulation. 

In one experiment, participants had to press a button as quickly as possible after being lightly touched on the face. When the 'sick' characters appeared, people reacted as if the faces were physically closer, even when they were further away. Their brains and bodies were responding as though a threat had entered their personal space. 

Brain scans showed increased activity in regions associated with detecting threats and regulating body responses. 

Even though no real germs were involved, researchers found from blood test results that there were changes in immune cell activity when people viewed the sick-looking characters. Specifically, they saw an uptick in innate lymphoid cells, a type of immune cell known to act as first responders, alerting the rest of the immune system to potential trouble. 

This reaction was so real that it mirrored what researchers see in people who’ve just had a flu shot, without any actual virus exposure. 

Your instinct to avoid someone who looks unwell isn’t just common sense, it might be part of a deeply wired, whole-body reaction designed to protect you 

So next time you see someone sniffling on the train, don’t just trust your gut, know that your body might already be gearing up for battle. 

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Episode Transcript

Speaker 1 (00:06):
You're listening to the Sunday Session podcast with Francesca Rudgin
from News Talks EDB.

Speaker 2 (00:13):
Joining me now with her science study of the week,
Doctor Michel de can Send.

Speaker 3 (00:17):
Good morning, Good morning. This is fantastic. This is good
because everybody around me is sick right now.

Speaker 2 (00:22):
I know you've had you've hit a sick household for
about a month.

Speaker 3 (00:25):
Everybody I know is sick.

Speaker 2 (00:26):
Oh, I know.

Speaker 3 (00:28):
This is great. So and this is really new research.
It's quite funny. So it's published in the journal Nature
and Neuroscience. If you want some Sunday morning reading, and
you probably do it. So if if you walk and
there's somebody who looks like they're ill, or they have
a bit of a sneeze or they've got a bit
of a weird rash on their face, you instinctively just
sidestep theud.

Speaker 2 (00:50):
It's we've just been talking about being at the movies.
If you're sitting at the movies and there's someone next
to your behind you who has a really bad snuff
of you know, considerable about a snot and you're just
sitting there cringing.

Speaker 3 (00:59):
Seven and everything.

Speaker 2 (01:00):
But the good thing is my body is actually going
ha ha well apparently so. So this is a great
study to because what they did is they took a
lot of volunteers two hundred and forty eight volunteers, and
they put v are virtual reality headsets on them. And
if you've not tried one of those before you it
can be really realistic. When you put these headsets on,
you can feel like real things are happening around you
and to you, even though they're not so. In these

(01:22):
VR headsets, they had videos of people walking towards you,
getting really close into your personal space. And it started
with people just with neutral expressions, just sort of walking
past you as if they would if you're walking on
the street. And then they did people who were fearful,
people who looked afraid. And then they had people who
walked at you who were visibly sick and they either

(01:43):
looked sick, ruddy nose, whatever, or they had a skin wresh.

Speaker 3 (01:46):
And as these people are walking towards you, they gave
you a button and they said, they said, when you
feel like this person is too close to you, it's
in your personal space, pressed the button and as you
can imagine, the people who walked towards you who looked
like they were sick, you pushed the button way and
you did with other people, and so your brain automatically

(02:08):
tries to increase your personal space when they see somebody
coming at you with an allus. That's fine, that's sort
of you do that naturally. But what is interesting about
this study is they then did brain scans and they
did blood tests on these people, and what they found
is that our brain scans, we had an increased activity
in the regions associated with detecting threats and regulating body

(02:31):
responses only when the sick looking people and they're not
even real people, right, the virtual people were walking towards us.
So immediately your brain is going, uh uh uh, there's somebody.
They're a threat. Let's flight, orf flight, Let's put something
into action. So your brain is responding. But this is
what is so cool. So they took blood tests of
these people in the vo headsets directly after they were

(02:54):
exposed to whoever they were exposed to win the virtual reality,
and they found an uptick in something called the innate
lymphoid cells in your blood. And these are the cells
that are known to act as sort of the first
response cell, first respond to cells whenever they think there's
an immune threat and they kick off your immune system
that there's going to be potential trouble ahead. Get ready,

(03:15):
get ready to fight whatever that is. What so interests
is it? In this study as well as the VR people,
they also got a whole bunch of other volatiers and
basically gave them a flu shot and then measured their
blood after they gave them the flu shot. And these
immune cells, so in a flu shot, there's an actual virus,
like it's a doignative virus, but your body is exposed

(03:35):
to the virus and your immune cell's kick in and go, okay,
we've gotta fight this denatured flu virus. The immune cells
had exactly the same response whether or not you were
just looking at somebody who looked like they were sick
or you actually had the flu shot. And this is
the first time it's ever been measured that your body
can actually trigger an increase in your immune cereresponse just

(03:57):
by seeing somebody who is sick versus having to be
exposed to the virus. I don't know if they discovered this,
but do some of us sort of have lazy immune systems?
Do We also one of these people in the viata
and they did a big It was a reasonab study
ate two hundred and forty eight volunteers all their immune
systems kicked off as soon as they saw somebody was

(04:18):
sick coming into their personal space, which shows that our
body is smarter than we think. So when you do
feel a little bit ikey to somebody at the movies
is coughing behind you, don't worry because your body is
actually kicking off an immune response in preparation for what
it thinks is about to fly at it through the
mucus of that starty person behind you as they're sitting
too close and joining on their pod. It was all
going really well there.

Speaker 2 (04:38):
That was all feeling really positive to surve it.

Speaker 3 (04:41):
But at the Michelle love it. Thank you so much.
Where can we find the study Nature Neuroscience.

Speaker 2 (04:46):
Fantastic, Thank you so.

Speaker 1 (04:47):
Much, Michelle. For more from the Sunday session with Francesca Rudken,
listen live to News Talks it'd be from nine am Sunday,
or follow the podcast on iHeartRadio.