Statistical studies in immunity : smallpox and vaccination / by John Brownlee.

  • John Brownlee
Date:
1905
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Licence: In copyright

Credit: Statistical studies in immunity : smallpox and vaccination / by John Brownlee. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    [From Biometrika, Vol. IV. No. 3. November, 1905.] STATISTICAL STUDIES IN IMMUNITY. SMALLPOX AND VACCINATION. By JOHN BROWNLEE, M.A., M.D., Glasgow. In writing this paper on smallpox and vaccination I have no intention of entering into any controversy upon the subject. The fact that vaccination protects against smallpox is assumed, and consideration is alone given here to the relationship between vaccination, revaccination, and smallpox, in so far as the facts throw light upon the growth, decline, or establishment of immunity in persons who have passed through one or other of these infections. I would rather have chosen for this investigation some other disease, but as an inquiry of this kind is essentially statistical there was no other series of figures available. The disadvantage of choosing vaccination and smallpox arises from the fact that the former is to a considerable extent different from the latter, and though there seems good reason for believing that vaccination is a disease caused by the parasite of smallpox so modified as to have lost one stage in its life history, yet the fact that it protects chiefly against the second stage of smallpox causes the immunity relationship to be of a more complex character than is desirable. Before proceeding, however, to consider the relationship of smallpox to vacci- nation one fact demands special preliminary notice: that is the change which has taken place in the age at which vaccinated persons are attacked by smallpox. All over the country from the earliest period of last century for which statistics are available there has been a steady increase in the mean age at which such persons have been attacked by smallpox. This is quite distinct from the rise in the mean age at death, shown by the combined mortality statistics of the vaccinated and unvaccinated which is com- monly and correctly looked upon as largely due to the protective influence of vaccination upon the younger members of the community. What I refer to is a process which applies specially to the vaccinated, and which does not seem to admit of any complete explanation from the point of view of alteration in the character of the population. In London, for instance, between the years 1836 Biometrika iv 40