As high-profile cases have shown, causes, coincidences and effects mean
that balancing risks and benefits is not always a straightforward task.
Pity the small boy. When I was a lad, there were no vaccinations
against measles, mumps and chicken pox, so when someone local had a dose
of a disease I was marched round to be infected. I realise now that
measles exposed me to around a 1 in 500 chance of death (see later), but
there wasn’t much choice back then, and no doubt it was character
forming.
Nowadays, of course, we have vaccines to do the job of
small children. But as successful as campaigns have been in saving
countless lives, some have aroused strong emotions, as a result of
ticking several fear-factors. First, we inject healthy people, usually
vulnerable children, and it’s imposed, either through pressure or by
legal compulsion. If your child is to attend a kindergarten in, for
example, Florida, they must have been vaccinated
against the following: DTaP – diphtheria, tetanus, pertussis (whooping
cough); Hepatitis B; MMR – measles, mumps, rubella (German measles);
polio and varicella (chicken pox). Added to this is the fact that there
can be side-effects. And finally, multinational corporations make a heap
of money out of this mass medicalisation.
All of which is true.
Little wonder, then, that claims that vaccination may cause adverse
outcomes such as autism find a ready audience.
Health check
But
we can work out roughly the risks without immunisation by tracking the
course of a disease like measles over the decades. In England and Wales
in 1940, just over a decade before I was born, there were 409,000 measles cases, of which 857 died – a ‘case fatality rate’ of 0.2%, which is also that quoted by the Centers for Disease Control and Prevention
(CDC) in the US. In other words, the 1 in 500 chance of death I
mentioned earlier. Vaccination started in the 1960s, and by 1990 the
number of cases had dropped to 13,300 with one fatality. Since 1992,
there have been no childhood deaths from measles in the UK, only as
adult consequences from early infections.
So it seems rather a
good thing to be vaccinated and, rather like stopping smoking, it is
also good for the people around you. This is because of herd immunity,
which means that sufficient people are immune so that an infection does
not turn into an epidemic. The current English vaccination rates for measles
(as of 2009) are 88%, up from 80% in 2003 – but still not back to the
92% level in 1995, let alone the 95% recommended by the World Health
Organization (WHO). In 2010, US vaccination coverage for children between 19 and 35 months of age was below 90% in eleven states.
Measles
is the first M in the MMR vaccination, and coverage went down after the
highly publicised claim in 1998 that MMR was associated with autism. This
has now been discredited, although it continues to have strong
supporters in the US – just try searching on “vaccine autism”. And its
impact continues to be felt far and wide. After an outbreak of measles in Liverpool
in February 2012, the UK’s Health Protection Agency revealed that 7,000
children under five years of age had not received their full measles
vaccine.
Risk assessment
The real problem
is that with any mass intervention there will always be bad occurrences
that happen around the time of the jab – essentially coincidences. For
example, in September 2009 a headline in the UK newspaper Daily Mail
declared that “Schoolgirl 14 dies after cervical cancer jab”,
quoting the head teacher as saying, “During the session an unfortunate
incident occurred and one of the girls suffered a rare, but extreme
reaction to the vaccine.” Three days later reports revealed
that the girl had cancer and the death was coincidental: however this
was not headline news, and this tragic event is used repeatedly on
websites as proof of the dangers of the HPV vaccine.
But sometimes
the reports are real. A classic example occurred in 1976 when a new
strain of swine flu was identified in Fort Dix, New Jersey. Fearful of a
repeat of the 1918 epidemic, a mass vaccination campaign began, and 45
million people were immunised.
Two events led to the abandonment of the programme by the end of the
year. First, there were around 50 reported cases of Guillain-Barré
syndrome - a gradual paralysis that is now thought to have been former
US president Franklin D Roosevelt’s condition. Eventually 500 cases were reported among vaccinated people – an increased risk
of around 10 in a million for the disease – and 25 people died. The
second reason for stopping the programme was that the epidemic never got
out of Fort Dix – nobody else had the flu and so there seemed no upside
to balance out the possible risk of Guillain-Barré syndrome. The
Director of the CDC was later sacked, but he still believes the vaccination programme was the correct response.
That
said, not all flu vaccines have the same risks. Following the UK swine
flu outbreak in 2009, nine cases of Guillain-Barré syndrome were
diagnosed within six weeks of vaccination; however, the eventual conclusion
was that this would be expected by chance alone. But Finland and Sweden
have reported increased rates of narcolepsy – sudden paralysis and
sleepiness – in children after the swine flu vaccination, and this is
still being investigated.
Balancing risk
As
the MMR saga showed, disproving an association is difficult and can
take a long time, if indeed ever. Sometimes a change is made even
without absolute proof of guilt. Thimerosal is a preservative used in
some vaccines and contains mercury, and has long been accused of harming
children. The CDC say there is “no convincing evidence of harm”, but in
1999 it was agreed that it should be “reduced or eliminated in vaccines as a precautionary measure”.
The
official line that the overall benefits of vaccination outweigh any
risks ignores the way in which imposed and highly visible harms, however
rare, are seen very differently from potential downstream benefits,
which can never be confirmed and seem ‘virtual’ in societies where the
risks of infectious diseases are so low.
It is a different matter in less-developed societies: for instance, the WHO report that there are still 140,000 deaths from measles each year, one every four
minutes. And, as we have seen in England, these are preventable.
Vaccination has already made huge inroads: there used to be 2.6 million
deaths a year from measles worldwide. Eradicating measles is seen to be a
feasible goal, and the days of being dragged round to someone’s house
to get infected are thankfully over. But as the numbers show, whatever
the potential risks of vaccinations are, they pale in comparison to the
risk in shunning what is often our best option for eradicating deadly
infectious diseases.
