Europeans cowardly and unnatural. Cowardly, because they are
afraid of putting their children to a little pain; unnatural, because they
expose them to die one time or other of the small-pox.’[16] (Voltaire,
himself a survivor of smallpox, supported the English approach.)
In 1759, mathematician Daniel Bernoulli decided to try and settle
the debate. To work out whether the risk of smallpox infection
outweighed the risk from variolation, he developed the first-ever
outbreak model. Based on patterns of smallpox transmission, he
estimated that variolation would increase life expectancy so long as
the risk of death from the procedure was below 10 per cent, which it
was.[17]
For modern vaccines, the balancing act is generally far clearer. On
one side, we have overwhelmingly safe, effective vaccines like MMR;
on the other, we have potentially deadly infections like measles.
Widespread refusal of vaccination therefore tends to be a luxury, a
side effect of living in places that – thanks to vaccination – have seen
little of such infections in recent decades.[18] One 2019 survey found
that European countries tended to have much lower levels of trust in
vaccines compared to those in Africa and Asia.[19]
Although rumours about vaccines have traditionally been country-
specific, our increasing digital connectedness is changing that.
Information can now spread quickly online, with automated
translations helping myths about vaccination cross language barriers.
[20] The resulting decline in vaccine confidence could have dire
consequences for children’s health. Because measles is so
contagious, at least 95 per cent of a population needs to be
vaccinated to have a hope of preventing outbreaks.[21] In places
where anti-vaccination beliefs have spread successfully, disease
outbreaks are now following. In recent years, dozens of people have
died of measles in Europe, deaths that could easily have been
prevented with better vaccination coverage.[22]
The emergence of such movements has drawn attention to the
possibility of echo chambers online. But how much have social media
algorithms actually changed our interaction with information? After all,
we share beliefs with people we know in real life as well as online.