It is an intriquing situation when there appears to be a conflict between
logic and evidence. Your initial reaction Andrew was a very logical response
as it is logical to assess the risk before proceeding with an intervention
and as you say, the risk of catastrophic consequences from childhood
diseases is remote in healthy children. As a mother of 5 children I have
taken quite an interest in this issue myself. I like to know what I am
giving my children, the reason for it being recommended and what the
evidence says.

Another logical question is why don't we have confidence in the immune
system of healthy children. I am not aware of any studies that have looked
at whether there is a better response to the childhood diseases from
strategies that strengthen the immune system compared to vaccination.
Reports I have read of children with serious complications of these
childhood diseases seem to include mainly children who have other diseases
and conditions, childhood cancers and other conditions that compromise the
immune system. Even if you argue the herd immunity approach to protect the
vulnerable, some of the vaccines used are live vaccines and there have been
reports of people contracting the condition from a recently vaccinated
child. And what about the increasing number of reports of non-specific viral
conditions in adults (that appear very similar to the childhood viruses) who
were vaccinated as children. Could vaccination programmes be responsible for
delaying the exposure and manifestation of these common childhood diseases
and shifting the problem to a different sector of the community? What about
the differences between natural immunity and immunity from vaccinations? I
can think of many other such questions that don't appear to have been
satisfactorily answered yet isn't this what an evidence-based approach
should do? It seems to me that sometimes the `evidence' is built on to
enthusiasm, anecdotal experiences and/or flawed assumptions - so although
the evidence as such appears quite robust - the starting point is a problem.

I have found it an interesting exercise to look at the natural history of
these viruses and their virulence over time, as well as what happened when
vaccines were introduced. Our Ministry of Health has collected this
information for over 100years and produces updates in the annual reports (as
do other countries). The graphs often start from when vaccination programmes
commenced and you can clearly see a steady decline in mortality. However,
when you go back further before vaccines were introduced the same steady
decline can be seen - with no particular change at the stage vaccines were
being used (although some plateau out). Although scarlet fever is not a
problem in NZ I was interested to see that a graph from the UK showing the
mortality from this disease. The graph revealed a similar downward curve to
the other childhood diseases - yet there is no vaccine for scarlet fever.
Maybe other factors (eg improved nutrition, sanitation and other public
health measures) have had a more significant influence in the decline in
mortality than we have assumed, or maybe the decline in mortality is a
manifestation of the natural history of a virus - that it becomes less
virulent in a population over time.

Certainly food for thought!

Unfortunately I have found it difficult to debate these issues and discuss
my questions as people seem very polarised about such matters and become
very emotive about vaccination issues. People seem either very pro or very
anti, but hopefully those of you on the list are neither of these as you
presumably value discussion and debate about the evidence (and the
interpretation of it), as well as about the gaps in our knowledge and the
unanswered questions.

Judi Strid
Women's Health Action
Auckland
New Zealand


> -----Original Message-----
> From: Andrew Jull [SMTP:[log in to unmask]]
> Sent: Tuesday, January 23, 2001 8:40 AM
> To: [log in to unmask]
> Subject: MMR
>
> Debate around immunisation always seems to attract strong responses. I
> would
> agree with Edmund Jessop that the issue is one of communication, but
> suggest
> that the strength of the responses is because they lie at the juncture of
> personal values and public communication. I would be interested in any
> evidence exploring the relationship between different communication
> strategies and uptake of immunisation, particularly MMR.
>
> From a personal perspective, when deciding whether my children should have
> the MMR, my first reaction was that I had these childhood diseases myself,
> with no obvious impact (apart from time lost from school and extra work
> for
> my mother), so why should I cause my kids the distress of further
> immunisation for such "safe" diseases? Being aware of the epidemiology
> (risk
> of death from encephalitis etc) did not allay this, as the risk is small
> enough that my response was not that my kids were going to die if they
> were
> not immunised, but that they were unlikely to die. As I say these were my
> first responses before my training kicked in and reflect the difficulties
> of practising EBH. But perhaps they may be a guide to public responses
> regarding MMR.
>
> Is anyone aware of any qualitative evidence exploring what influences
> parental decisions to have their children immunised for MMR?
>
> Andrew Jull
> Clinical Nurse Consultant
> Auckland Hospital
> NEW ZEALAND