Diphtheria Can't Be Stopped by Vaccination!
Dmitriy K. Yuryev (Posted to bionet.virology and bionet.immunology
on 15-16 May 96.)
Strictly saying, diphtheria vaccine is a not a true vaccine; it belongs
to a family of so called toxoids. It boosts immune response not against
the microbe itself but against its toxin (which actually causes all symptoms
of the disease). Such immunity inactivates toxin and relieves the symptoms
of disease (almost excluding lethal cases) if it is caught soon after vaccination.
But the obvious trouble is that this vaccine does absolutely no harm to
microbe itself, so it can not hinder its multiplying nor diminish probability
of catching infection.
Obviously, for this type of vaccines decline of reported (grave) cases
of diphteria after starting mass immunization can not be taken as a proof
of their ability to stop epidemic. Such decline is defined by the fact
that significant part of epidemic becomes "invisible" for medical
statistics: asymptomaticl and mild cases of diphteria are simply not registered.
Yet, as far as I know, there are no other proofs.
Several recent reviews (Science, 10Mar.95, 267:1416; JAMA, Apr.95,273(16):765)
gave a reason to think so. First, the style of these papers leaves no doubt
that using word "vaccine" as a name for diphtheria toxoid is
officially considered as a sufficient proof of its efficacy in stopping
epidemic. Second, announcing in these papers the obviously unattainable
recommendations about necessity to ensure 5-fold (!) vaccination of 95%
population to stop epidemic directly imply that practice clearly shows
serious problems in stopping diphteria epidemics with toxoid.
Juxtaposition of these two monstrously incompatible points was actually
the only reason for me to write this note. I have no specific competence
in diphtheria nor much interest to look any further. So, I would be very
glad if somebody is interested to investigate this theme. I can't believe
that this problem was never discussed at all. More likely, it is possible
to find some discussions dated by the time of institution of diphtheria
vaccination. I guess, there had to be people who worked on developing regular
vaccine against diphtheria who had no reason to "disregard" intrinsic
flaws in idea of toxoids.
The most important practical consequence of this interpretation is that
if diphtheria toxoid is really unable to stop epidemic then talking about
"herd immunity" against diphtheria is most absurd. And, therefore,
prophylactic mass immunisation against diphtheria is absolutely meaningless
until the epidemic has been started in close neighborhood.
And, finally, it appears worth to be stated directly that writing this
note was not possible without uneasy suspicions that vaccinology is governed