Vaccination (inoculation with vaccine, the virus of cowpox; Lat. vaccinus, 'of a cow') is the pure cultivation of artificial cowpox (vaccinia) in the human system with the object of protecting from smallpox (variola). The practice was introduced by Jenner (q.v.) in 1796-98, and gradually made way in spite of the fierce opposition both of the medical profession and of the public. Natural cowpox is a vesicular disease of the teats and udders of milch-cows, and the vesicles contain lymph which has, when inoculated, the property of transmitting the same disease. Jenner thought that cowpox was derived from the ailment in horses' heels called Grease (see WEED), and Loy actually succeeded in producing vaccinia from this source. Ceely and Badcock produced vesicles by variolating cows (i.e. infecting them with smallpox), and Voigt, Simpson, Hime, and King claim to have succeeded, though Chauveau and Klein failed. There is no doubt protective vaccine material can be obtained from either natural cowpox, horsepox, or smallpox passed through the cow. Sir John Simon believes that cowpox is the smallpox of the cow, and this opinion appears to be justified by positive results. Artificial cowpox has been chiefly maintained since the time of Jenner by means of humanised lymph. The use of arm-to-arm instead of preserved lymph is essential to the success and efficacy of vaccination with humanised lymph. Ordinarily lymph can be taken from a vaccinated arm at the end of a week, and it should be carefully selected from the best formed vesicles upon the healthiest children. The Vaccination Acts of 1867, 1871, and 1874 made vaccination effectively compulsory in England, so that it is estimated about 95 per cent. are vaccinated. The registrar of the district must within a week of the registration of a birth deliver to the parent a 'notice of requirement' of vaccination of the child within three months of its birth in England and Ireland, and within six months in Scotland. In America vaccination is not compulsory, except indirectly, in most of the states of the Union, nor in Canada. It is in Victoria, Western Australia, and Tasmania, but not in New South Wales.
Calf-lymph.—Since 1880 the use of animal lymph has increased to an enormous extent; the use of this lymph is now obligatory in Berlin and in Saxony in public vaccination stations, and an establishment for the preparation of it exists in Berlin. Consequently there is now no active agitation against vaccination in Germany. Bovine lymph from spontaneous cowpox at Beaugency in France was introduced into the United States in 1870, and has almost entirely superseded humanised lymph. In Britain also animal vaccine has recently been found to be as manageable as humanised lymph, the station being at Lamb's Conduit Street in London. The lymph used was sent over to England in 1882 from Laforêt, near Bordeaux, from a calf vaccinated with material taken from a case of spontaneous or natural cowpox. Five calves are vaccinated every week in fifty or sixty places on the abdomen. The ordinary course run by the disease is that between three and four days after insertion of the lymph a line of inflammation appears, which on the fifth day is distinctly vesicular, and yields lymph. On the sixth day the vesicle is broader, and on the fourteenth or fifteenth day the crust is fully formed, and generally falls off about the end of the third week. The course of the vesicle is more rapid in the calf than in children, and the lymph is best on the fifth day. Part of the lymph is collected on points and sent up to the National Vaccine Establishment. A calf yields sufficient lymph for vaccinating 400 or 500 children, and more than 30,000 children have been vaccinated by Dr Cory from calf to arm since the station was started. The effects of lymph from the calf and of lymph from the infant are identical; he failed in twenty-two cases out of 5005 at the first trial, but succeeded the second time. Five vesicles are produced on each child, and the insertion success with calf-to-arm lymph is the same as that with human arm-to-arm vaccination, 96.7 per cent. Only about 1 per cent. of the cases were brought back for 'sore arms,' and these were mainly due to improper applications, plasters, &c. Out of 32,000 cases there were also thirty-eight cases of eczema and lichen, and sixteen of erysipelas.
Re-vaccination.—The claim first made on behalf of vaccination was that of equal immunity from smallpox as compared with the immunity resulting from 'inoculation,' without the danger of spreading infection. The protection was originally expected to last a lifetime, but now re-vaccination is thought advisable as early as ten years if in presence of smallpox. Re-vaccination, as a rule, gives protection for the remainder of life. Assuming that the State intends to compel complete insusceptibility, compulsory re-vaccination would be necessary. The impermanence of infantile vaccination has been ascribed to deterioration of the lymph in successive generations; but mere number of generations does not make it less effective any more than passing the contagion of smallpox through a great many generations diminishes its virulence. In 1887 in the smallpox hospitals of the Metropolitan Asylums Board out of 53,000 cases of smallpox treated 41,061 had been vaccinated. No case of smallpox has occurred during fifty years among nurses and attendants at smallpox hospitals who have been re-vaccinated before going on duty.
Protective Power of Vaccination.—The report (1884) of Sir George Buchanan shows the vast superiority as a protective against smallpox of public vaccination as compared with private vaccination, which is not supervised. Before vaccination was made compulsory, the smallpox mortality in England was double that of any other European state where it was compulsory, and 70 to 80 per cent. of the smallpox mortality in Great Britain and Ireland occurred under five years of age. Since the Vaccination Act of 1871 was passed, the smallpox mortality in the whole country has been greatly reduced, especially in the case of young children. The decennial reports for 1851-60 and 1861-70 show that the actual rates of smallpox mortality, at ages five and upwards, remained at a stand-still, and that the rates under five years had enormously decreased. Study of the London epidemics of 1876-78 and 1881-82 showed that the marked increase of smallpox at ages over five had really been the expression of an alteration in the behaviour of smallpox in this country. Statistics show that the fatality of smallpox varies (1) with the amount of vaccination possessed by the individual; (2) according to the age of those attacked; (3) according to the quality of the vaccination scars in those attacked. In addition to Mr Marson's well-known tables, Dr Gayton's report to the Metropolitan Asylums Board of 10,403 cases of smallpox shows the fatality per cent. of the attacks. He divides the scars according as they are 'good' or 'imperfect.' With four "good" scars there is an absolute immunity from death up to the age of fifteen, and with "good" scars, whether one, two, or three, there is an absolute immunity of death from smallpox up to the age of five. When all the 'good' and 'imperfect' vaccinations are grouped together, it shows that from ten to fifteen and from fifteen to twenty years of age the 'good' vaccination afforded just three times the amount of protection against smallpox death that the 'imperfect' vaccination afforded. The protection against attack is of chief avail in the first few years after vaccination, and infantile vaccination cannot be relied on as lasting through adult life. According to Dr Gayton, whereas there was no death amongst those under five years who had 'good' vaccination, the percentage was 56.5 amongst the unvaccinated; from five to ten the corresponding figures were 9 and 35.2, from thirty to forty 9.5 and 40.7 per cent., and over forty 12.5 and 43. From Dr Barry's report on the Sheffield epidemic, it appears that the rate of attack among the vaccinated and unvaccinated of the population generally is one attack among the vaccinated under ten years of age for every twenty attacks among the unvaccinated; and over ten years one attack among the vaccinated for every five unvaccinated attacks. In invaded houses, irrespective of quality of vaccination, there were under ten years one vaccinated to eleven unvaccinated attacks; and over ten years one vaccinated to 2.4 unvaccinated attacks. In the children under ten years of age, where there was no visible mark, or one cicatrix only, 75.7 per cent. had discrete or mild attacks, and 24.3 confluent or severe attacks; where there were two cicatrices, the corresponding figures were 88 and 12; where three cicatrices, 95 and 5; where four or more cicatrices, 97.5 and 2.5. The fatality per cent. was shown to vary according to the amount of vaccination as shown by the cicatrices without reference to their quality. With increased number and better quality of the scars produced the severity and fatality of smallpox has decreased. Diminution in the amount of fatality and mortality corresponds with the nearness of the time to the vaccination at which the patient was attacked by smallpox. The greatest protection against attack is found near to the operation of primary vaccination or re-vaccination. The greater the remoteness from the date of vaccination, the greater has been the incidence of smallpox and the fatality upon those attacked. The safeguarding is essentially in the years immediately subsequent to vaccination, and the gain especially as regards infant life. Were this decline due to improved sanitation, we should naturally expect the fall to be shared by persons of all ages. During 1872-87 the fall in the general death-rate has been 9 per cent., and in other zymotic diseases 9 per cent. for measles and 1 per cent. for hooping-cough, as compared with 72 per cent. for smallpox. The fall in 'fever' mortality has been nearly as much, but it has been at all ages.
Objections to vaccination are made on the ground of alleged injurious effects resulting from the practice. Complaints of public vaccination in England and Wales in 1888 were only ten in number out of 689,323 children vaccinated. Inquiry by medical inspectors showed two of these cases to be measles and hooping-cough concurrent with vaccination, two to be skin eruptions following on vaccination, and the remainder to be cases of erysipelas or other similar disease. The Registrar-general reports that in from forty to fifty cases annually vaccination is mentioned among the causes of death, and from 1888 onwards all such cases were to be made the subject of careful investigation. Most of the accounts of 'vaccinal accidents' come from abroad. In 1883 certain cases of erysipelas followed the vaccination of soldiers at Dortrecht, Holland, with humanised lymph received from a vaccination office. Seven men were attacked three days after the operation, and three died; but no official report of the cases has been published, and it is uncertain whether other cases of erysipelas were prevailing at the time. The risk of erysipelas is greatest during the second week. On the 30th December 1880 it is alleged that syphilis was communicated by vaccination to fifty-eight Zouaves in Algiers. The statement that two healthy children served as vaccinifers for 280 men, and that those fifty-eight men were operated on by lymph taken from one single child, is opposed to all experience in vaccination. Mr Ernest Hart says, 'during the twenty years in which there has been systematic inspection of public vaccination in England, some millions of vaccinations have been performed, but in no single instance have the government inspectors of vaccination been able, after the most rigid inquiry, to find one single case of syphilis after vaccination.' Impetigo contagiosa, which is caused by pediculi, has been attributed to vaccination at Elberfeld in 1887, and in the island of Rügen in 1885. Acute septicæmia followed a series of vaccinations in March 1885 at Asprières, Aveyron, France, and six children died. The lymph was taken from a vesicle which had been opened twenty-four hours previously, and had been contaminated. The preponderance of evidence goes to show that leprosy is not inoculable, but when it occurs is due to food, such as decayed fish; leprosy has declined in Norway and Sweden since vaccination was introduced.
Opponents of the practice have attempted to show not only that smallpox has not been reduced by vaccination, but that it has actually been increased; alleging that in France the greatest smallpox mortality occurred in the best vaccinated departments, and vice versa. The returns were, however, shown to be very incomplete and unreliable. Körösi showed that Keller's statistics on the dangers of vaccination were falsified.
Substitutes for Vaccination.—Improved sanitation has been credited with the decline in the prevalence and mortality from smallpox. Dr Creighton, however, thinks that sewerage, water-supply, and nuisance removal have little influence upon smallpox. New South Wales has a system of compulsory notification with heavy fine for neglect, and power of isolating persons and things infected, or exposed to infection, for three weeks.
The Royal Commission of 1889 reported in 1897, 11 out of 13 signing the report that vaccination has a protective effect, greatest for nine or ten years, and then rapidly diminishing, but never vanishing entirely; revaccination restores the protective power. The diseases alleged to arise through vaccination are real, but are inconsiderable in comparison with the amount of vaccination performed, and are diminishing from the precautions used. Calf lymph is to be preferred; isolation, though valuable, is not a satisfactory substitute for vaccination. Two commissioners disapproved of compulsory vaccination.
The Vaccination Act of 1898 made many changes in the law. Hereafter the public vaccinator must go, if asked, to the home of the child, glycerinated calf lymph is to be used if required, and parents not vaccinating their children are exempted from penalty if they satisfy the magistrates that they conscientiously believe vaccination would be prejudicial to the health of the child.
See Cokeman, Vaccination, its History and Pathology (1899); Reports of Commissions (1871, 1889); Seaton, Vaccination (1868); Ballard, Vaccination (1868); Warlomont, Manual of Animal Vaccination (Eng. trans. 1885); Vaccinia and Variola, with bibliography, by the present writer (1887); and handbooks of the law by D. P. Fry (1875) and by a 'barrister-at-law' (1888); and the Index Medicus. Vaccination and Smallpox, by E. J. Edwardes (1892), is a plea for compulsory re-vaccination. Expressly in defence of vaccination are Ernest Hart, The Truth about Vaccination (1880), J. C. M'Vail, Vaccination Vindicated (1888), and Körösi (as above). Directly hostile are A. R. Wallace, Vaccination Proved Useless and Dangerous (1889); C. Creighton, Jenner and Vaccination (1888) and The Natural History of Cow-pox and Syphilis (1888); E. M. Crookshank, History and Pathology of Vaccination (1890); and the publications of the London Society for the Abolition of Compulsory Vaccination (founded 1887). The town of Leicester has taken a very prominent part in the anti-vaccination agitation. See also GERM, INOCULATION, JENNER, SMALLPOX; and for the analogous application of inoculation, HYDROPHOBIA.