VACCINATION (from Lat. vacca, a cow), the term originally devised for a method of protective inoculation against smallpox, consisting in the intentional transference to the human being of the eruptive disease of cattle called cow-pox (vaccinia). The discovery of vaccination is due to Dr Edward Jenner (<?..), at the time a country medical practitioner of Berkeley, in the vale of Gloucester, whose investigations were first published in 1798 in the form of a pamphlet entitled An Inquiry into the Causes and Effects of the Variolae Vaccinae, etc. Many years previously, while he was an apprentice to a medical man at Sodbury, near Bristol, his attention was directed to a belief, widely prevalent in Gloucestershire during the latter half of the 18th century, that those persons who in the course of their employment on dairy farms happened to contract cow-pox were thereby protected from a subsequent attack of small-pox. In particular, his interest was aroused by a casual remark made by a young countrywoman who happened to come to the surgery one day for advice, and who, on hearing mention made of small-pox, immediately volunteered the statement that she could not take the disease, as she had had cow-pox. On coming up to London in 1770, to finish his medical education, Jenner became a pupil of John Hunter, with whom he frequently discussed the question of the possibility of obtaining protection against small-pox. On his return to his native village of Berkeley in 1773, to practise as a medical man, he took every opportunity of talking over and investigating the matter, but it was not until May 1796 that he actually began to make experiments. His first case of vaccination was that of a boy eight years of age, named James Phipps, whom he inoculated in the arm with cow-pox matter taken from a sore on the hand of Sarah Nelmes, a dairymaid, who had become infected with the disease by milking cows suffering from cowpox. It was apparently not until 1798 that he made his first attempt to carry on a strain of lymph from arm to arm. In the spring of that year he inoculated a child with matter taken directly from the nipple of a cow, and from the resulting vesicle on the arm of the child first operated upon, he inoculated, or, as it may now be more correctly termed, " vaccinated," another. From this child several others were vaccinated. From one of these a fourth remove was successfully carried out, and finally a fifth. Four of these children were subsequently inoculated with small-pox the " variolous test " without result. The success of many such experiments, in his own hands and in those of his contemporaries, led Jenner to express his belief a mistaken one, as events have proved that the protective influence of vaccination would be found to last throughout the lifetime of the person operated on. Obviously he did not realize the fact that the data at his disposal were insufficient for the formation of an accurate judgment on this point, since time alone could prove the exact duration of the protection originally obtained. Subsequent experience has demonstrated that, as has been well said by a writer in the Edinburgh Review, " even after efficient vaccination a slow progress away from safety and towards danger is inevitable, and re-vaccination at least once after childhood is necessary if protection is to be maintained. " In applying to cow-pox the term " variolae vaccinae," Jenner gave expression to his belief that this disease was in reality nothing more nor less than small-pox of the cow. But soon it was discovered that if there were small- such a malady as " small-pox of the cow," there pox and was a i SO; as j) r L O y fi rs (- satisfactorily demonstrated, <wpox. a sma n_p OX o f the horse, which, under the name of " grease," was resorted to from time to time as a source of vaccine lymph. Jenner had, indeed, put forward the suggestion that " grease " was a necessary antecedent to cowpox; but even taking this term to have been used by him in the sense of horse-pox, he was, in all probability, mistaken in his assumption. At the same time, however, there can be little doubt that these two diseases are very closely allied, if indeed they be not identical. As evidence of a definite relationship between human small-pox and cow-pox, it may be mentioned that whereas, prior to the introduction of vaccination, epidemics of these disorders frequently arose concurrently, the so-called " natural " cow-pox has now in great measure disappeared. There is, moreover, no appreciable difference in the minute anatomical appearances characteristic of the eruption following on inoculation of one or other of these two affections in the human subject. But of far greater importance in this connexion are the results obtained by numerous observers who, in various parts of the world, and almost from the time of Jenner onwards, have set themselves the task of attempting, by experimental methods, to solve the problem of the true relationship of variola to vaccinia. vAs the outcome of this work it may now be definitely stated that small-pox lymph, more especially, as the present writer has shown, if obtained from the primary vesicle of a case of the inoculated form of the disease, by passage through the system of the calf can be so altered in character as to become deprived of its power of causing a generalized eruption, while inducing at the site of inoculation a vesicle indistinguishable from a typical vaccine vesicle; and, more important still, that when transferred again to man, it has by such treatment completely lost its former infectious character. Such being the case, it may fairly be asserted that cow-pox, or rather that artificially inoculated form of the disease which we term vaccinia, is nothing more nor less than variola modified by transmission through the bovine animal. An outbreak of small-pox, indeed, may be turned to account for raising, by appropriate experimental methods, a fresh stock of vaccine lymph.
There is much evidence to prove that the results following on vaccination are due to a specific contagium, and, moreover, that the particular micro-organism concerned is capable of existing, during one period of its life-cycle, in a resting or spore form, in which condition it is more resistant to the germicidal effects of glycerine than is the case with non-sporing microbes. Advantage is taken of this fact, in the method devised by the present writer, and now employed officially in England, as also on the Continent and in America, for ensuring the bacteriological purity of vaccine lymph. Up to the present, unfortunately, no satisfactory method has been discovered by which the micro-organism of vaccinia can be unfailingly cultivated on artificial media while still retaining its specific properties.
The publication in 1896 of the final report of the English Royal Commission on Vaccination, in which the various phases of the vaccination question are discussed on the basis of evidence obtained from witnesses of all shades of opinion during a period extending over no less than six years, considerably simplifies the task of dealing with this subject. The Royal Commission, originally numbering fifteen members, 1 with Lord Herschell as president, was appointed in May 1889, the 1 The original Commissioners were Lord Herschell, C. Bradlaugh, Dr Bristowe, Dr Collins, Sir C. Dalrymple, J. S. Dugdale, Q.C., Prof. M. Foster, Sir E. H. Galsworthy, Sir Guyer Hunter, J. Hutchinson, Sir James Paget, J. A. Picton, Sir William Savory, S. Whitbread, F. Meadows White, Q.C. Mr Bradlaugh, Dr Bristowe and Sir William Savory died during the progress of the inquiry. Only one of the vacancies thus caused was filled up, Mr J. A. Bright having been appointed on the death of Mr Bradlaugh.
terms of reference being as follows : " To inquire and report as to (i) The effect of vaccination in reducing the prevalence of, and mortality from, small-pox. (2) What means, other than vaccination, can be used for diminishing the prevalence of small-pox; and how far such means could be relied on in place of vaccination. (3) The objections made to vaccination on the ground of injurious effects alleged to result therefrom; and the nature and extent of any injurious effects which do, in fact, so result. (4) Whether any, and, if so, what means should be adopted for preventing or lessening the ill effects, if any, resulting from vaccination; and whether, and, if so, by what means, vaccination with animal vaccine should be further facilitated as a part of public vaccination. (5) Whether any alterations should be made in the arrangements and proceedings for securing the performance of vaccination, and, in particular, in the provisions of the Vaccination Acts with respect to prosecutions for non-compliance with the law."
The evidence given before the Royal Commission was published at intervals in a series of Blue-books, but, as stated, it was not until August 1896 that the final report made its appearance. As regards the effect of vaccination in reducing the prevalence of, and mortality from, small-pox, the following conclusions were arrived at, Dr Collins and Mr Picton alone dissenting: " (i) That it diminishes the liability to be attacked by the disease. (2) That it modifies the character of the disease and renders it (a) less fatal, and (b) of a milder or less severe type. (3) That the protection it affords against attacks of the disease is greatest during the years immediately succeeding the operation of vaccination. It is impossible to fix with precision the length of this period of highest Erotection. Though not in all cases the same, if a period is to be xed, it might, we think, fairly be said to cover in general a period of nine or ten years. (4) That after the lapse of the period of highest protective potency, the efficacy of vaccination to protect against attack rapidly diminishes, but that it is still considerable in the next quinquennium, and possibly never altogether ceases, (5) That its power to modify the character of the disease is also greatest in the period in which its power to protect from attack is greatest, but that its power thus to modify the disease does not diminish as rapidly as its protective influence against attacks, and its efficacy, during the later periods of life, to modify the disease is still very considerable. (6) That re-vaccination restores the protection which lapse of time has diminished, but the evidence shows that this protection again diminishes, and that, to ensure the highest degree of protection which vaccination can give, the operation should be at intervals repeated. (7) That the beneficial effects of vaccination are most experienced by those in whose case it has been most thorough. We think it niay fairly be concluded that where the vaccine matter is inserted in three or four places, it is more effectual than when introduced into one or two places only, and that if the vaccination marks are of an area of half a square inch, they indicate a better state of protection than if their area be at all considerably below this."
For the evidence, statistical or otherwise, on which these conclusions are based, the Reports of the Royal Commission should be consulted. But reference may here be made to two facts of which proof is overwhelming, (i) Small-pox, in pre-vaccination days a disease of infancy and childhood like measles at the present day has in the United Kingdom become a disease mainly of adults. The shifting of age-incidence can only be accounted for by the custom of vaccination in infancy. To this day, when small-pox attacks young unvaccinated children, it is found to be as virulent as, or even more virulent than, small-pox in the unvaccinated at higher ages. On the other hand, small-pox is practically unknown among well-vaccinated children. When, quite exceptionally, such children have been attacked, the disease has been so trivial [in character as to be liable to escape recognition altogether. (2) Medical men, nurses and other persons exposed to the disease habitually protect themselves by efficient re-vaccination, and when this precaution has been taken, never contract small-pox.
The clinical activity and bacteriological purity of the lymph employed for vaccination; the skilful performance of the operation itself; the making an adequate number Boldest of insertions of lymph over a sufficient area; the vaccinaobservance of precautions needful for ensuring strict tloa. asepsis, both at the time of vaccination and subsequently until the vaccination wounds are soundly healed all these are matters to be regarded as essential to " efficient vaccination." Certain principles in respect of them are generally recognized, and in the case of public vaccinators, whose work comes under government inspection, a series of instructions on these several points are prescribed by the Local Government Board. First in regard to lymph. That which is now almost universally employed in Great Britain is glycerinated calf lymph, the use of which has entirely superseded, in public vaccinations, the arm-to-arm method which for many years previously had been employed as the best means then attainable of ensuring the activity and comparative purity of the lymph. Glycerinated lymph, under proper conditions, usually retains its potency for many weeks or months; but nevertheless, in certain circumstances at present imperfectly understood, is liable to become gradually weakened, and even eventually to become altogether inert. Possibly the condition of the calves from which the lymph is obtained, especially as regards their general health and the suppleness or the reverse of their skins, or exposure of the lymph to the action of light or to a high temperature, are of special importance. Consequently, in order to ensure the best results from its use, it is not only necessary that great care should be exercised in its manufacture, but it is also advisable that the lymph should be employed for vaccination as soon as possible after bacteriological examination has demonstrated its freedom from suppurative and other extraneous microorganisms. As regards the carrying out of the operation itself, it is somewhat unfortunate that there exists no official definition of what constitutes a " successful vaccination," and in consequence it is open to any practitioner to give a certificate of successful vaccination in cases where but one minute vesicle may have been produced. It is to be feared that such certificates are too frequently given, and it cannot be too strongly urged that vaccination of this sort involves incomplete protection. The standard laid down by the Local Government Board the production, namely, of a total area ot vesiculation of not less than half a square inch, divided among four separate vesicles or groups of vesicles, not less than half an inch from one another has for the most part proved easily attainable in practice, and it is much to be desired that in private as in public work the attainment of this standard should be aimed at in every instance. The protection afforded by a primary vaccination tends gradually to diminish, and eventually to disappear more or less completely, with the lapse of time. In consequence, it is desirable that the operation should be repeated at the age of from seven to ten years, and thereafter, if it be possible, at intervals during later life. The final report of the Royal Commission thus summarizes the evidence as to the value of such additional procedure:
" Where re-vaccinated persons were attacked by, or died from, small-pox, the re-vaccination had for the most part been performed a considerable number of years before the attack. There were very few cases where a short period only had elapsed between the revaccination and the attack of small-pox. This seems to show that it is of importance, in the case of any persons specially exposed to the risk of contagion, that they should be re-vaccinated, and that in the case even of those who have been twice re-vaccinated with success, if a long interval since the last operation has elapsed, the operation should be repeated for a third, and even a fourth time."
It not unfrequently happens that in the case of a re-vaccination the process runs a somewhat different course from that witnessed in a typical primary vaccination. In a successful re- vaccination, the site of the operation may be distinctly reddened and somewhat irritable by the second day, while papules will probably make their appearance about the third to the fifth day. The papules may or may not develop further into vesicles and pustules. Occasionally a re-vaccination appears to fail altogether; but, as pointed out by the Royal Commission, it is advisable, as in the case of a primary vaccination, to make further attempts with lymph of known potency before concluding that the individual is really insusceptible.
In a certain small proportion of cases the operation of vaccination has been followed, after a longer or shorter interAiieged val, by various complications, of which by far the injurious most important are those of an inflammatory nature, effects. suc jj as cr y S ip e i aSj which are not peculiar to vaccination, but which constitute the danger of any local lesion of the skin, however caused. During the many decades in which vaccination from arm to arm was practised, in many millions of children, a few authenticated cases were recorded in which there was reason to believe that syphilis could have been invaccinated. Such an occurrence could at no time have happened if proper care had been taken by the vaccinator; and now that the use of calf lymph has become practically xxvn. 27 universal, the possibility of such occurrence in the future may be disregarded, since the calf is not capable of contracting this disease. Tubercle in its various forms and leprosy have also been included in the list of possible complications of vaccination, though without any sufficient proof. The employment of calf lymph, treated with glycerine after the manner first advocated by S. Monckton Copeman, will obviate any such danger, for even if tubercle bacilli or the streptococcus of erysipelas were by chance present in the lymph material when collected, it has been found experimentally that they are quite unable to survive prolonged exposure to the action of a 50% solution of glycerine in water. Leprosy is not communicable to the calf. In view of the frequency of various skin eruptions in infancy, it is to be expected that in a proportion of cases they will appear during the weeks following vaccination. Eczema and impetigo in particular have, post hoc, been attributed to vaccination, but no direct connexion has been proved to exist between the operation and the occurrence of these disorders. In section 434 of the final report of the Royal Commission on Vaccination the extent to which other inoculable diseases are liable to complicate vaccination is thus summed up:
" A careful examination of the facts which have been brought under our notice has enabled us to arrive at the conclusion that although some of the dangers said to attend vaccination are undoubtedly real, and not inconsiderable in gross amount, yet when considered in relation to the extent of vaccination work done, they are insignificant. There is reason, further, to believe that they are diminishing under the better precautions of the present day, and with the additions of the future precautions which experience suggests, will do so still more in the future." (S. M. C.)
Legislation making vaccination compulsory was first introduced in Bavaria (1807), Denmark (1810), Sweden (1814), Wiirttemburg, Hesse and other German states (1818), comPrussia (1835), the United Kingdom (1853), German puisory empire (1874), Rumania (1874), Hungary (1876), v t f' aa ' Servia (1881), Austria (1886). But in many cases there had been earlier provisions indirectly making it necessary. In the same way, though there is no federal compulsory law in Switzerland, most of the cantons enforce it; and though there is no statutory compulsion in France, Italy, Spain, Portugal, Belgium, Norway, Russia or Turkey, there are government facilities and indirect pressure, apart from the early popularity of vaccination which made it the usual practice. In the United States there is no federal law, but many of the separate states make their own compulsion either directly or indirectly, Massachusetts starting in 1809.
The benefit of vaccination proved itself in the eyes of the world by its apparent success in stamping out small-pox; but there continued to be people, even of the highest competence, who regarded this as a fallacious argument post hoc, ergo propter hoc. The cause of " anti-vaccination " has had many followers in England, and their persistence has had important effect in English legislation. Under the provisions of the Vaccination Act 1898, and of the Vaccination Order (1898) of the Local Government Board, with some minor changes in succeeding acts, numerous changes in connexion with vaccination administration and with the performance of the English operation were introduced, in addition to the super- legisiasession of arm-to-arm vaccination, by the use of a "' glycerinated calf lymph. Thus, whereas by the Vaccination Acts of 1867 and 1871 the parent or person having the custody of any child was required to procure its vaccination within three months of birth, this period by the act of 1898 was extended to six months. Again, parents were relieved of any penalty under the compulsory clauses of the Vaccination Acts who afforded proof that they had, within four months of the birth of a child, satisfied a stipendiary magistrate, or two justices in petty sessions, that they conscientiously believed that vaccination would be prejudicial to the health of the child. Moreover, proceedings were not to be taken more than twice against a defaulting parent, namely, once under section 29 of the act of 1867, and once under section 31 of the same act, provided that the child had reached the age of four years. Finally, the public vaccinator was now required to visit the homes of children for the purpose of offering vaccination with glycerinated calf lymph, " or such other lymph as may be issued by the Local Government Board." The operative procedure in public vaccinations was formerly based on the necessity of carrying on a weekly series of transferences of vaccine lymph from arm to arm; and for the purposes of such arm-to-arm vaccination the provision of stations, to which children were brought first for the performance of the operation, and again, after a week's interval, for inspection of the results, was an essential. The occasional hardships to the mothers, and a somewhat remote possibility of danger to the children, involved in being taken long journeys to a vaccination station in bad weather, or arising from the collecting together in one room of a number of children and adults, one or more of whom might happen to be suffering at the time from some infectious disorder, are a few of the reasons which appeared to render a change in this regulation desirable; as a matter of fact, it would appear that nothing but good has arisen from the substitution of domiciliary for stational vaccination. There have naturally been some curious discussions before the magistrates as to what is " conscientious " or not, but the working of the so-called " conscience clause " by no means justified the somewhat gloomy forebodings expressed, both in Parliament and elsewhere, at the time of its incorporation in the act of 1898. On the contrary, its operation appeared to tend to the more harmonious working of the Vaccination Acts, by affording a legal method of relief to such parents and guardians as were prepared to affirm that they had a conscientious belief that the performance of the operation might, in any particular instance, be prejudicial to the health of the child.
AUTHORITIES. Acland, " Vaccinia," Allbutt and Rolleston, System of Medicine (1906); Baron, Life of Jenner; Henry Colburn (London, 1838); Copeman, Vaccination: Its Natural History and Pathology (Milroy Lectures) (Macmillan, London, 1899); " Modern Methods of Vaccination and their Scientific Basis," Trans. Royal Med. and Chir. Society (1901-2); M'Vail, "Criticism of the Dissentient Commissioners' Report," Trans. Epidemiological Society (1897); Reports of the Royal Commission on Vaccination (1889- 1896); "The History and Effects of Vaccination," Edinburgh Review, No. 388 (1899); Vaccination Law of German Empire (Berlin, 1904).
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)