Protracted complications and constitutional changes in a child after vaccination are not scientifically proven. I do, however, believe that the fever period of vaccination is quite favorable to the out break of a latent syphilis or tuberculosis, as is the case with tuberculosis after measles. Therefore, it, is well to vaccinate during the first year of life, before tubercular infection has taken place.
Few facts in medicine can be so clearly demonstrated as the exter mination of smallpox by means of vaccination.
It may be said that vaccination may, perhaps, prevent a subsequent infection with vaccine, but not with variola. Regarding this point, a great number of careful experiments were made at the beginning of the nineteenth century, where secondary inoculation with variola was prac ticed after vaccination to study its efficacy. The immunity of vaccinated persons against both processes was clearly proved.
The principal objection of those opposed to vaccination, not to speak of the great fear of the transmission of syphilis, is the belief that in spite of vaccination one may be attacked by variola. The gradual recurrence of a marked revaccination effect is analogous to t his fact, well known since the early part of the nineteenth century, that just as revaccination (the accelerated reaction) is almost never just like the first vaccination, variola of the vaccinated differs similarly from that of the unvacci nated in its course. It is as a rule abortive, and very rarely fatal. The early hamiorrhagic form which attacks vaccinated robust men is, perhaps, an exception and is, no doubt, analogous to that form of revac cination which, during its rapid course, produces a large areola.
How long does the protection against smallpox last? It is difficult to answer this question accurately, because of the many individual vari ations. Statistics on this point, vary between twelve and twenty years. The protection seems to be of shorter duration among children than that following vaccination of adults. Statistics on successive revaeci nation somewhat enlighten us. We may assume that those whose revaccination was successful, that is, resulted in a well-developed pustule, Avouhl, if infected with variola, have developed a smallpox eruption.
Of 1342 children, whom Heim revaccinated at the age of one to five years, 2 per cent. showed reaction resembling a normal first vaccination. Among 141S children, between five and ten years of age, the percentage was .5.8. Among children between ten and fifteen years, 9.6. We may conclude, then, that of the first group 2 per cent., of the last as high as 10 per cent., were predisposed to the development of variola.
From a practical point of view, the efficacy of the German law regarding vaccination has been sufficiently demonstrated. It requires vaccination during the first year and revaccination in the eleventh year. Most men are again vaccinated on entering the army. Although we can not with certainty predict that an individual is protected against smallpox, the danger from a case of smallpox is so slight that an exten sive spread of an epidemic rarely occurs.