theGIST Issue 12

Science in the Spotlight
How is measles
motivating
policy
change?
In August 2019, the UK lost
its 'measles-free' status. More
recently, the first case of polio in
27 years was documented in a 3-
year-old boy from Malaysia. There is
concern that we will see a rise in
frightening news headlines like
these if appropriate action isn't
taken. These cases have fuelled discussions
about the decline in uptake
of vaccines (which could
prevent these reported cases) and
the possibility of introducing new
vaccine policies which may help
stop preventable problems like this
happening in the future. Strikingly,
the World Health Organization
(WHO) has stated that vaccine hesitancy
is in the top 10 list of global
threats. So what does it really mean
to lose the 'measles-free' status?
This is appointed by the WHO and is
defined as an area or a country that
has had no regular transmission of
the infection in that designated area
in 12 months [1]. The UK was given
it's 'measles-free' status in 2016,
successfully maintaining it for less
than four years.
"the World Health Organization has stated
vaccine hesitancy is in the top 10 list of
global threats"
The rise in measles cases, and
the loss of the 'measles-free' status
in the UK, Greece and several other
countries in Europe and around the
world, may have been caused by
multiple factors. Firstly, with
measles 'under control', it is
thought that people have forgotten
how serious and life-threatening
measles can be. The measles virus
is, in fact, one of the most infectious
diseases on the planet. Symptoms
include fever, light sensitivity
and a rash, which in most cases
subside in a week to 10 days [2].
However, in some individuals, there
can be complications which can
prove fatal. Additionally, measles
infection has a significant impact on
the immune system in the short
and long-term. In the first instance,
measles decreases the number of
white blood cells in the body. It is
these cells which are responsible for
fighting other infections. This means
during measles infection, individuals
will be more vulnerable to other
pathogens. In the longer-term, a recent
study has shown that measles
can impact immunological memory
[3].
This study involved sequencing
antibody genes from children before
and after measles infection. It was
found that memory immune cells,
trained to recognise and fight secondary
infection, were absent from
the blood in children after measles.
It was also found that the immune
system was more immature postmeasles
infection which means other
diseases the child had not yet
been exposed to would also be more
difficult to develop immunity against.
This study has shown that a vaccine
against measles infection is not only
protection against measles itself, but
against the many other infections a
person may be exposed to in their
lifetime.
It is also important to remember
that it is the most vulnerable populations
in society that are at the
highest risk of getting infected.
Young babies, the elderly and people
who are immunocompromised, who
cannot get vaccinated themselves,
are reliant on the rest of the population
being vaccinated and keeping
the disease in the population low.
Another reason attributed to the
rise in measles cases is the misinformation
and disinformation
spread surrounding the safety and
efficacy of vaccines. Research
from the Netherlands demonstrates
the exponential damage a
rise in measles can have and the
importance of large vaccine coverage
in a population. The MMR vaccine,
protecting against measles,
mumps and rubella, is 97% effective
after 2 doses, and 93% after
only 1 dose [4]. Yet, a discredited
study from 1998 regarding this
seems to stick in people's minds.
Andrew Wakefield published a paper
in a well known medical journal
linking the MMR vaccine to
autism. There have been many articles
since showing there is no link
and the paper has been retracted,
with Wakefield being found guilty
of fraud. Additionally, a lot of mistrust
may come from disproportionate
reporting in the media.
Up until recently, measles cases
were rare and therefore the frightening
symptoms were not talked
about regularly. Yet a rare side effect,
such as an allergic reaction
from a vaccinated child, could gain
a lot of media coverage and fuel
the anti-vaccination movement. In
the case of the Wakefield study, it
gained a lot of media coverage at
the time, despite the very small
sample size in the study as well as
other questionable methods used.
20 years on, social media makes
the spread of misinformation and
disinformation even easier. One
study has revealed that 50% of
parents with children under 5
came across negative messages
regarding vaccination online [5].
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