Papers relating to the history and practice of vaccination.

  • Great Britain. General Board of Health.
Date:
1857
Catalogue details

Licence: Public Domain Mark

Credit: Papers relating to the history and practice of vaccination. Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

    45/300
    His conclusions, so far as they relate to my present point, are as follows That the fatality of small-pox, when it attacks the unvaccinated, is 350 per thousand; that its fatality to such vaccinated persons as it infects is, taking- them indiscriminately, 70 per thousand; hut, distinguishing vaccinated persons into two classes,—those (1) who have been vaccinated in the best known manner, and those (2) who have been badly vaccinated,—the fatality of small-pox, if it infects the former, will be 5 per thousand; if it infects the latter, 150 per thousand : that the risk of the one will be thirty times the risk of the other. Such being the almost perfect security which well-performed infantine vaccination confers against death by small-pox, it remains to be considered whether here is the necessary limit of Jenner’s benefaction to mankind. The remnant of danger is not great. But, such as it is, can it be prevented ? Thirty years ago, when first it became notorious that small-pox might affect a certain proportion of persons previously and properly vaccinated, this partial failure of protection was explained on one or other of two suppositions :—Either (it was said) the vaccine con- tagion,* in its transmission through so many human subjects, must have lost by degeneration some of that specific protective influence which, in its former condition, it exerted on the human economy; or else there must be essentially something of uncertain constancy, some- thing impermanent or liable to be impermanent, in the privileges which vaccination confers. To the former of these possibilities I shall presently revert, and will now only remark, that, viewed as an alternative to the other, it was judged to be an insufficient explanation. For what chiefly attracted attention was this : not that persons vaccinated by the surgeons of 1820-30 with the lymph of 1820-30 were less protected against small-pox than persons who had been vaccinated in 1798; but, generally, that persons who had been vaccinated ten or fifteen or twenty years, and who, during this interval, had perhaps repeatedly resisted small-pox, would at length, in a certain proportion of their number, yield to the infection. This had most frequently happened during times when small-pox was severely epidemic among the unvaccinated; and the first notice of the fact on a large scale in Scotland in 1818-20 merely meant that then, for the first time, large masses of persons with vaccination of many years standing were exposed to the test of a strong epidemic influence. Under this ordeal it had become evident that, for some vaccinated persons, the insusceptibility conferred by cow-pox was not of life-long duration. And from careful analysis of cases it was shown, that this lesser protectedness of certain vaccinated persons bore at least some proportion to the number of years which in each case had elapsed since vacci- nation. Some proportion, I say:—for (1st) there were not materials to prove any uniform rate of increase from year to year; and, (2d) the increase, such as it was, apparently * I avoid speaking of tlie vaccine lymph, as being weakened by transmission through many human subjects, because this expression often represents a misunderstanding of what really occurs in the propagation of disease by morbid poisons. Lively arguments for the necessary degeneration of the vaccine contagion have proceeded on a belief that the original cow-pox at each vaccination simply dilutes itself with certain passive juices of the vaccinated body, that it thus of course gets weaker and weaker at every stage, till at its thirty-fifth succession it is reduced— according to Dr. Nicolai—to at least the 8,809,458,688th fraction of its original power. This argument founds itself on a radical misapprehension of the infective process in question. What essentially marks the infective action of cow- pox, small-pox, and similar morbid poisons, is, that under their fermentative influence some ingredient of the infected body converts itself into their likeness. The material contained within certain vaccine vesicles is not a something which has been transfused into the body, but a something which has been generated within it by a specific decom- position of its own proper substance ; and the original lymph, which acted as a ferment to this process, has very probably completed its decay and altogether passed from the scene before those new vesicles begin to show themselves. Successive dynamical infections do not imply a perpetuation (with corresponding infinitesimal subdivision) of the original efficient; or Nicolai’s argument might equally have been used to prove that the power of human procreation could not but cease soon after the days of Adam. Almost perfect security given by good vaccination. Further inquiry into post- vaccinal small- pox. Two supposed causes of its occurrence. Lapse of time as a cause.