Fine
aerosols
Small
droplets
Large
droplets
Inhaled
virus
Virus in eyes,
nose, or
mouth
Contaminated
surfaces
Virus on
hand
Breathing
Virus on
hand
Adjust scenario
Activity
Distance
Location
Physical contact
Surface type
Ventilation
Talking
Talking loudly
Singing
Exercising
Eating
Coughing
Silent
Small room
Large room
Outdoors
Less than 2m
More than 2m
Off
On
No direct contact
Shared table
Shared items
Direct contact
Wood
Metal or ceramic
Paper or card
No mask
Cloth mask
Surgical mask
FFP3 mask
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No mask
Cloth mask
Surgical mask
FFP3 mask
No
Yes
No
Yes
No
Yes
No
Yes
Face covering
Face covering
Visor
Perspex screen
Visor
Surface cleaning
Gloves
Hand
hygiene
Gloves
Hand hygiene
Respiratory
hygiene
Visualising expert estimates of covid-19 transmission
What might be the best ways of protecting ourselves from covid-19?
© 2021 BMJ Publishing Group Ltd.
Interactive
Disclaimer:
This infographic is not a validated clinical decision aid. This information is provided without any representations,
conditions, or warranties that it is accurate or up to date. BMJ and its licensors assume no responsibility for any aspect of
treatment administered with the aid of this information. Any reliance placed on this information is strictly at the user's own
risk. For the full disclaimer wording see BMJ's terms and conditions: http://www.bmj.com/company/legal-information/
Infected person
Uninfected person
This graphic simulates two people meeting, and
what they can do to reduce the risk of catching
covid-19. The colours show how much infectious
virus is likely to be passed on, based on the best
estimates of 26 international experts.
Reset
graphic
KEY
Low
High
All
Split between pathways
Quality of
evidence
0%
100%
50%
Target
Source
The values above will change depending on the activity selected, which is likely to
affect the proportion of droplets of different sizes entering the environment
Dependency
The values above will change depending on the “physical contact” scenario
selected, which is likely to affect the proportion of large droplets landing on
different surfaces
Dependency
The values above will change depending on the “physical contact” scenario
selected, which is likely to affect the transfer of virus to other surfaces
Dependency
Humidity and room temperature may affect the transmission of infectious virus,
and every room has its own natural air leakage rates and air flow patterns - affected
also by the movement of people and how they are facing each other/how much
they are talking etc. There has simply not been enough work on the effects of
ventilation on virus transmission to be sure about its effects.
And another line...
Key uncertainties
The blue dot represents the experts’ best
estimate of this value. The light blue area
shows where they think the value is most
likely to be (their 95% confidence interval)
Any other coloured areas represent
alternative estimates given by some experts
The ‘star ratings’
show how strong
the experts think
the supporting
evidence is for
these default
values:
...confidence
that the findings
would hold true
in reality
Close
explainers
Very high...
Very low...
The position of these dots represent how much
we think each of the pathways, precautions,
and scenarios would allow the virus to pass
through - from 0% (no protection) to 100%
(total protection). The default positions were
estimated by a group of 26 experts worldwide
The precautions you could take to
protect yourself from covid-19 affect
one or more of the disease ‘pathways’
in the diagram
The blue dot represents the experts’ best
estimate of this value. The light blue area
shows where they think the value is most
likely to be (their 95% confidence interval).
Any other coloured areas represent other
“camps” of opinion that might suggest that
one group of experts have a different, and
equally plausible, idea of the likely value
The ‘star ratings’
show how strong
the experts think
the supporting
evidence is for
these default
values
...confidence
that the findings
would hold true
in reality
Close explainers
Very high...
Very low...
The position of these sliders represent how
much we think each of these precautions
would affect these disease pathways - from 0
(no protection) to 1 (total protection). The
default positions were estimated by a group of
experts worldwide - but you can alter these to
see ‘what if they are wrong’
>
Different scenarios affect the colour of
the pathways, increasing or decreasing
it at the point it leaves one of the
circular “nodes” in the diagram
The blue dot represents the experts’ best
estimate of this value. The light blue area
shows where they think the value is most
likely to be (their 95% confidence interval)
Any other coloured areas represent other
“camps” of opinion that might suggest that
one group of experts have a different, and
equally plausible, idea of the likely value
The ‘star ratings’
show how strong
the experts think
the supporting
evidence is for
these default
values
...confidence
that the findings
would hold true
in reality
Close explainers
Very high...
Very low...
The position of these sliders represent how
much we think each of these precautions
would affect these disease pathways - from 0
(no protection) to 1 (total protection). The
default positions were estimated by a group of
experts worldwide - but you can alter these to
see ‘what if they are wrong’
This diagram shows the different
pathways that can be taken by the virus
that causes covid-19 when it transfers
between two people. The darker the
colour, the higher the estimated risk.
Next
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These transmission routes
can be affected by factors
such as the behaviour of the
people, and the environment
that they meet in.
Next
Previous
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There are several measures that can be
used to protect ourselves, such as
wearing masks or washing hands.
These menus will add and remove
these measures and show the likely
effect on transmission.
Begin
Previous
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Read about the creation of this graphic on bmj.com
DRAFT