经济学人2016年3月26日A jab in time
员工思想动态分析-解酒的水果
Vaccination
A jab in time
Some
Western countries have lower vaccination rates
than poor parts of
Africa. Anti-vaxxers are
not the main culprits
Mar 26th 2016 |
From the print edition
ERADICATING a
disease is the sort of aim that rich countries
come up with, and
poor ones struggle to reach.
But for some diseases, the pattern is reversed.
These
are the ailments for which vaccinations
exist. Many poor countries run highly
effective vaccination programmes. But as
memories of the toll from infectious
diseases
fades across the rich world, in some places they
are making a comeback.
The World Health
Organisation (WHO) reckons that vaccines save 2.5m
lives a
year. Smallpox was eradicated in 1980
with the help of a vaccine; polio should
soon
follow. In both cases, rich countries led the way.
The new pattern looks very
different.
The trend is most evident for measles, which
is highly contagious. At least 95% of
people
must be vaccinated to stop its spread (a threshold
known as “herd
immunity”). Although usually
mild, it can lead to pneumonia and cause brain
damage or blindness. The countries with the
lowest vaccination rates are all very
poor,
but many developing countries run excellent
programmes (see chart).
Eritrea, Rwanda and
Sri Lanka manage to vaccinate nearly everyone. By
contrast
several rich
countries, including America, Britain, France and
Italy, are below
herd immunity.
Last year
Europe missed the deadline it had set itself in
2010 to eradicate
measles, and had almost
4,000 cases. America was declared measles-free in
2000;
in 2014 it had hundreds of cases across
27 states and last year saw its first death
from the disease in more than a decade. The
trends for other
vaccine-preventable diseases,
such as rubella, which can cause congenital
disabilities if a pregnant woman catches it,
are alarming, too.
This sorry state of affairs
is often blamed on hardline “anti-vaxxers”,
parents who
refuse all vaccines for their
children. They are a motley lot. The Amish in
America
spurn modern medicine, along with
almost everything else invented since the
17th
century. Some vegans object to the use of animal-
derived products in
vaccines’ manufacture. The
Protestant Dutch Reformed Church thinks vaccines
thwart divine will. Anthroposophy, founded in
the 19th century by Rudolf
Steiner, an
Austrian mystic-cum-philosopher, preaches that
diseases strengthen
children’s physical and
mental development.
INTERACTIVE: Explore vaccination coverage and
measles cases worldwide from
1980 to 2014
In most countries such refuseniks are only
2-3% of parents. But because they
tend to live
in clusters, they can be the source of outbreaks.
A bigger problem,
though, is the growing
number of parents who delay vaccination, or pick
and
choose jabs. Studies from America,
Australia and Europe suggest that about a
quarter of parents fall into this group,
generally because they think that the
standard
vaccination schedule, which protects against
around a dozen diseases,
“overloads”
children’s immune systems, or that particular
vaccines are unsafe.
Some believe vaccines
interfere with “natural immunity”. Many were
shaken by a
claim, later debunked, that there
was a link between autism and the MMR
vaccine,
which protects against measles, mumps and rubella.
In America, some poor children miss out on
vaccines despite a federal
programme to
provide the jabs free, since they have no regular
relationship with
a family doctor. Some
outbreaks in eastern Europe have started in
communities
of Roma (gypsies). Members of this
poor and ostracised minority are shunned by
health workers and often go unvaccinated.
Several governments are trying to raise
vaccination rates by making life harder
for
parents who do not vaccinate their children. A
measles outbreak last year
that started with
an unvaccinated child visiting Disneyland and
spread from
there to seven states prompted
California to make a full vaccination record a
condition of entry to state schools. The
previous year, in a quarter of schools too
few
children had been vaccinated against measles to
confer herd immunity. A
dozen other states are
considering similar bills. After a toddler died
from
measles last year, Germany recently
started to oblige parents who do not wish
their children to be vaccinated to
discuss the decision with a doctor before they
can enroll a child in nursery. Australia’s new
“no jabs, no pay” law withdraws
child benefits
from parents who do not vaccinate, unless they
have sound
medical reasons.
Persuasion, a
fine art
There is, however, surprisingly
little evidence that tough laws make a big
difference to vaccination rates. European
countries that are similar in most
respects
(such as the Nordics) may have similar rates for
jabs that are mandatory
in one country but not
in another—or very different rates despite having
the
same rules. Rates in some American states
where parents can easily opt out are
as high
as in West Virginia and Mississippi, which have
long allowed only
medical exemptions.
And
strict rules may even harden anti-vaccination
attitudes. Australia had
previously made
exemption conditional on speaking to a doctor or
nurse about
the benefits of vaccines. The new
rules mean fewer chances to change parents’
minds. Research suggests that making it harder
to avoid the most important
vaccines may make
it more likely that people who strongly oppose
vaccination in
general shun optional ones,
says Cornelia Betsch of the University of Erfurt.
More important, say public-health experts, is
to boost confidence in the safety of
vaccines
and trust in the authorities that recommend
them—both badly
damaged in many European
countries by pastpublic-health mis-steps, such as
a
scandal with contaminated blood supply in
France from the late 1990s. The best
way to
handle a vaccine scare is to express empathy and
promptly share the
results from investigations
of alleged adverse reactions, says Heidi Larson of
the
London School of Hygiene and Tropical
Medicine. British authorities’ dismissive
response to the MMR scare failed to reassure
worried parents.
One promising new approach is
to keep track of the vaccine myths circulating in
cyberspace and rebut each one as it appears.
This requires tracking information
from search
engines and following anti-vaccination websites
and parents’ forums.
On one such forum,
worriers say they have scoured government and
vaccine-manufacturer websites but feel
overwhelmed by information that they
regard as
inconclusive or contradictory. One mother seeks
advice on how to get
around California’s
“fascist” new rule. Another casts doubt on a study
on severe
allergic reactions to vaccines: 33
cases from 25m jabs, she says, seems “fishily
low”.
Some countries are starting
information campaigns that treat such concerns
with
respect. A parents’ organisation in
Bulgaria launched one recently, under the
auspices of the ministry of health
and the national association of paediatricians.
Its website is jargon-free and easier to
navigate than unwieldy official hubs.
France
is launching a national dialogue on vaccines this
spring, with a website
where citizens can swap
gripes, worries and advice.
Although vaccine-
hesitant parents often search for answers on the
internet, their
most trusted sources are
doctors and nurses. The WHO recently developed
guidelines to help health workers figure out,
through a questionnaire, which type
of worrier
a parent is—and how to alleviate specific
concerns. But recent
research from several
European countries shows that many doctors and
nurses
are also hesitant about vaccines, for
much the same reasons as their patients. In a
survey conducted in 2014, 16-43% of French
family doctors said they never or
only
sometimes recommended some of the standard
vaccines.
An additional problem is that many
adults were not immunised as children and
have
not caught up since. In the 1970s and 1980s, when
the measles vaccine was
new, many children did
not receive it, or got just one shot, which is now
known
not to be reliable in conferring
immunity. Some countries offer free catch-up jabs
to some adults when outbreaks flare up—usually
parents with small children
and health workers
in affected areas.
But such efforts have, on
the whole, been too little, too late. The return
of easily
preventable diseases that had all
but disappeared is a shame. A bigger shame
would be for governments to continue blaming
it all on ignorant parents.