The
CDC recently
released a study titled "
Historical
Comparisons of Morbidity and Mortality for Vaccine-Preventable Diseases
in the United States", just published in
JAMA
and
reported
on in the New York Times. It alleges to demonstrate that
vaccines were responsible for a preponderance of the decline in deaths
for most "vaccine-preventable" diseases.
You can almost hear the collective sigh of
relief. But is what they are reporting true?
In order to try and begin to understand whether or
not the CDC fairly made their case, some of the data concerning measles
and pertussis will be examined and discussed.
1) When comparing pre-vaccine cases/deaths
to post-vaccine cases/deaths, the years chosen appear to be those just
prior to introduction of the vaccine. Were all years for which
data exist considered, however, dramatic declines prior to introduction
of vaccine would be in evidence. For instance, the estimated
annual average pre-vaccine cases and deaths for measles were based on
the years 1953-1962. By then, the total number of deaths (see
below) and
death
rate per 100,000, however, had already dropped
significantly. Ignoring the earlier years falsely attributes most
of the decline in deaths to vaccination.
Click here (1,2)
for the CDC data upon which the death rates and incidence graphs are
based.
2) Although the pertussis vaccine was
introduced before the measles vaccine and hence an earlier pre-vaccine
period for pertussis, 1934-1943, was chosen, death incidence (see
below) and
death
rates still had declined significantly by the end of the
"pre-vaccine" period. Ignoring the earlier years in this case
also falsely attributes most of the decline in deaths to
vaccination.
Click here (1,2)
for the CDC data upon which the death rates and incidence graphs are
based.
*Note that these declines are even more dramatic when one considers
that the population was growing at the same time deaths from these two
diseases were declining.
3) For reasons that are unclear, they chose
the year 1914 as the beginning date for pertussis vaccine, even though
the vaccine was not deemed particularly effective or widely used in
those early days, and even though by their own admission, 1934-1943 was
"pre-vaccine". Was the purpose in starting with that date an
effort to make it seem that any early declines could be attributed to
vaccination, when, perhaps they should not be?
4) Cases and deaths reported as the "most
recent post-vaccine reported numbers", came from different years - 2006
for the "cases", 2004 for the "deaths". This is like comparing
apples and oranges and is not meaningful. It would have been
better to use the 2004 cases, if they only had the 2004 deaths, than to
use different years.
An interesting example of how cleverly a graph can
be devised can be seen in the MMWR.
Upon examination of their pertussis incidence and deaths
graph,
a number of important things become apparent. First, the CDC
inappropriately used a logarithmic scale to show the declines. A
logarithmic scale shows "rate of " change rather than absolute
change. This particular graph shows 90% declines.
The graph also indicates that the vaccine's
"minimum potency (was) established" around 1950 and that the "standard
unit" was established around 1955.
Now a 90% drop from 10 is more significant in
people terms than a 90% drop from 0.1. And, although it is not
easily discerned from the graph, most of the big drops in deaths
occurred prior to standardization of the pertussis vaccine. In
fact there were two approximately 90% drops by the time the standard
unit had been established.
Had the y-axis, which shows the incidence, plotted
absolute numbers rather than 90% rates of decline, as it does in this
graph, the huge declines prior to standardization would have been clear
as a bell.
When the y-axis is plotted properly, as it is in
the "pertussis deaths by year" graph above, it will show that
significant declines occurred even before the 1934-1943 CDC-designated
"pre-vaccine" period. But unless standardization added little to
nothing to pertussis vaccine effectiveness, "pre-vaccine" should extend
to around 1955, in which case the drop in deaths prior to vaccination
would be seen to be even more dramatic. (Click here
to see what the death rate would have looked like had the data been
properly and meaningfully graphed.)
Besides, given that the CDC has data going back as
far as 1922, why didn't they call 1922-1943 "pre-vaccine" rather than
start in 1934? Is it because the drop in deaths prior to
vaccination would have been shown to be even more striking?
All this lends credence to the notion that the
CDC, in the recent JAMA article, seems to be continuing its pattern of
ignoring the huge declines in deaths for these diseases prior to
vaccination.
They have a long history of a) exaggerating the
benefits of vaccines while at the same time ignoring and/or dismissing
their long-term risks and b) exaggerating the long-term consequences of
diseases. At least insofar as pertussis and measles are
concerned, this most recent article appears to be merely more of the
same. For those seeking increased confidence in at least those
particular vaccines, this study does not appear to be the place to find
it.
by Sandy Gottstein (aka
Mintz)
Among the many
Scandals
columns relevant to this discussion are the following:
Scandals:
Shoot First,
Don't Ask Questions Later;
Scandals:
Measles In The Vaccination Age: Is It Now
Deadlier? and
Scandals:
More confusing disease stats.
"Eternal vigilance is
the price of liberty." - Wendell Phillips (1811-1884), paraphrasing
John Philpot Curran (1808)