16 January 2021 | New Scientist | 11AS COVID-19 vaccine roll-out
begins in earnest in many
countries, there is an extra reason
to be cheerful. Such an outlook,
along with other personality traits
and the kinds of social interactions
we have, can enhance how our
bodies react to immunisations.
“There is now a large literature
that shows that these sorts
of psychological factors
influence how people respond
to vaccinations as measured by
magnitude of antibody response,”
says Anna Marsland, a psychologist
at the University of Pittsburgh
in Pennsylvania.
In one of the first studies of its
kind, in 2006, Marsland and her
colleagues found that people who
described themselves as energetic,
cheerful or relaxed produced
a 73 per cent greater antibody
response to vaccination against
the virally transmitted disease
hepatitis B than those who
regarded themselves as more
nervous, tense or angry.
Since then, numerous studies
have expanded our understanding
of the impact these so-called soft
drivers of immunity can have.
Other research, for instance,
has found that even your mood
on the day of an immunisation
can make a difference. Among
138 older people, those who were
in a positive state of mind on the
day of a flu shot were better
protected by the vaccine 16 weeks
later than those who were in a
less upbeat mood. The study
examined other factors that might
have an influence, such as sleep
and physical activity in the run-up
to the vaccination, but none of
these had a significant effect.
Similarly, optimism can act as
a vaccine boost, while neuroticism
is linked to a poorer antibody
response to immunisation.
Social connections can also
influence how well our body
responds to a vaccine. In one
experiment, 83 students receiving
a flu shot were asked to name up
to 20 people they knew well and
with whom they were in contact at
least once a month. At check-ups
one month and then four months
later, those who had listed fewer
than 13 friends produced
significantly fewer antibodies
to the influenza virus.
Similar effects have been found
with the hepatitis B vaccine:
students reacted better to it if
they felt they had someone wholistened to them when they
needed to talk or who could help
them if they were confined to bed.
Romantic love, too, appears
to be good for vaccinations. One
study by a team at the University
of Birmingham, UK, found that
older people who were highly
satisfied with a spouse or partner
they were cohabiting with saw
their antibody levels rise 10 per
cent higher on average in response
to the flu vaccine compared withthose who were single or in
unhappy relationships.
The link between emotions,
relationships and the immune
system makes sense from an
evolutionary perspective, says
Steve Cole at the University of
California, Los Angeles. In general,
our immune systems evolved
to have two basic settings, he
says: an antiviral one and an
antibacterial one.
In our evolutionary past, being
with people meant more exposure
to viruses, while being alone on
the savannah meant a greater risk
of wounds, be they from predators
or accidents, which require an
inflammatory, antibacterial
response, he says. “The immune
system doesn’t have an infinite
capacity and so it shifts resources
back and forth between different
modes of defence,” says Cole.
Even though things that stress
us out these days don’t routinely
injure us – think mortgages or
work deadlines – chronic stress
and loneliness might switch our
immune system from the antiviral
setting to the antibacterial one.In contrast, a positive emotional
style, says Cole, may help prevent
such an automatic switch to the
inflammatory setting when we are
feeling lonely – it is as if optimists
didn’t believe they might be
attacked by lions while alone.
Research, including randomised
trials, confirms this on a biological
level: kindness, optimism and
social inclusion have all been
shown to switch the genes of the
immune system away from an
inflammatory response towards
gearing the body to fight viruses.
When it comes to the
coronavirus vaccines, if they act
like other shots, says Marsland,
“there is reasonably consistent
evidence that psychological
factors will relate to the
magnitude of antibody response”.
Based on her work on hepatitis
B immunisations, Marsland
believes that such variations
may be more pronounced after
the first dose, levelling out after
the second one.
For Cole, the nub of the issue
lies in whether these factors will
influence how long the protection
will last. “That’s our big challenge:
how can we prevent this kind of
stress biology from quantitatively
impairing the vaccine responses,
so they look good at first, but they
decay relatively quickly,” he says.
Chronic stress in its many forms,
social isolation included, has been
repeatedly shown to undermine
the immune system and the
vaccine response.
The research is all the more
crucial given the mental toll of the
pandemic and the isolation that
can come with social distancing.
One thing is certain, however,
although stressing out about
your antibody production isn’t
the way to go, talking to a loved
one to boost your mood before
your coronavirus shot certainly
won’t hurt. ❚Knowing there are people
you can rely on can
amplify vaccine responseDGL^ IMAGES
/GETTY^ IMAGES10%
The boost in antibodies after a
flu vaccination for those happily
married or cohabitingImmune system
Marta Zaraska
Positive mood and good friends
can boost response to vaccines