English vaccination and small pox statistics : with special reference to the report of the Royal Commission, and to recent small pox epidemics / by Noel A. Humphreys.
- Humphreys, Noel A.
- Date:
- [1897]
Licence: Public Domain Mark
Credit: English vaccination and small pox statistics : with special reference to the report of the Royal Commission, and to recent small pox epidemics / by Noel A. Humphreys. Source: Wellcome Collection.
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![12 nmid, however, that the attack rate of small pox depends primarily upon the liability to contact with sources of infection, and that there is a source of fallacy in the attempt to calculate attack rates on the whole vaccinated and unvaccinated population of a large town. The bona fides of the investigations being, however, beyond question, it seems desirable to refer briefly to these statistics, although from a pro-vaccination point of view they are far out¬ weighed m importance and conclusiveness by the figures previously dealt with showing the almost absolute immunity from attack enjoyed by successfully re-vaccinated nurses and attendants in small pox hospitals. Dr. Barry arrived at the conclusion that Sheffield at the date of the epidemic, contained 266,797 vaccinated and 7,315 un- vaccinated persons of all ages, and that the small pox attack rate in these two classes of the population were 16 and 7-5 per cent, respectively. For reasons stated above, the value of these statis¬ tics is somewhat doubtful. No similar objections can be urged against Dr. Barry’s statistics of the attack rate of the vaccinated and unvaccinated inmates of houses invaded by small pox. These houses contained, it is reported, 4,419 children under 10 years of age stated to be vaccinated, of whom 353 or 7 9 per cent, were attacked; while of the 337 unvaccinated children of the same age, 228 or 67-6 per cent, were attacked. Above 10 years of age the attack rate among the vaccinated and unvaccinated did not differ so widely, being 28-3 and 53*6 per cent, respectively, proving, what now needs no proof, that the protective effect of infant vaccination decreases with the lapse of years. Dr. Savill shows that in 437 houses infected with small pox in Warrington, the attack rate was 4 4 pe** cent, among vaccinated, and 54’ 5 per cent, among un¬ vaccinated children aged under 10 years ; above 10 years of age the attack rate was 29-9 and 57*6 among the vaccinated and un¬ vaccinated respectively. Very similar results were reported con¬ cerning the attack rate in invaded houses at the epidemics in Dewsbury, Leicester, and Gloucester; the figures will be found in the following table :— Table X. Small Pox Attack Rate of Vaccinated and Unvaccinated Persons under and over 10 Fears of Age, in Five Towns in which Small Pox Fpidemics have recently occurred. [“ Final Report,” p. 65.] 1 Towns. 3 T>ate of Epidemic. 3 4 Attack Kate under 10. 5 6 Attack Rate over 10. Vaccinated. Unvaccinated. Vaccinated. Unvaccinated. Sheffield . 1887-88 79 67*6 28-3 K 3 '6 Warrington .... ’92-93 4-4 54'5 299 <!7'6 Dewsbury. ’91-92 10-2 5o‘8 277 c, V4 Leicester . ’92-93 25 3 5’3 22.2 47’6 Gloucester .... ’95-96 88 46'3 32-2 50-0 In view of these figures relating to invaded houses, it appears impossible to avoid the conclusion arrived at by the Commis¬ sioners, that the vaccinated at all ages are far less liable to be attacked by small pox than the unvaccinated, and that the advantage in this respect enjoyed by vaccinated children under 10 years of age is greatly in excess of that enjoyed at a more advanced period of life. Severity of Type of Small Pox amony Vaccinated and Unvaccinated. Nearly all English small pox hospital statistics during the past fifty years have shown that the type of small pox suffered by the vaccinated is, as a rule, far less severe than that to which the unvaccinated are liable. That small pox differs greatly in the degree of its severity is a well known fact; sometimes it is a comparatively trifling ailment, in other cases it is a very serious illness entailing the gravest after consequences. The most severe forms of the disease are known as malignant or haemorrhagic; the confluent type is less severe, but still of a very serious character. Milder types have been described as coherent and discrete, and the mildest as varioloid or simply “mild.” Much statistical information derived from the reports on recent epidemics was given to the Commissioners, bearing on the varying t}rpes of disease suffered respectively by vaccinated and unvaccinated patients in the small pox hospitals. It will only be possible here to refer very briefly to these statistics. Of 825 vaccinated cases in the Sheffield Borough Hospital in 1887-88, 85-5 per cent, were mild or discrete, 13 per cent, coherent, and only 1-5 per cent, confluent; the 280 unvaccinated cases included no varioloid or mild cases, 17*9 per cent, discrete, 62^5 per cent, coherent, and 19-6 per cent, confluent. All the 27 vaccinated children under 10 years suffered from the varioloid or discrete type; while 74-6 per cent, of the 67 unvaccinated children had the disease of the coherent, and 6 per cent, of the confluent type. Thus the pro¬ portions of severe and mild forms of the disease among the vaccinated and unvaccinated were practically almost exactly reversed. No explanation of these ratios except the fact of previous vaccination or otherwise of the patients suggested itself to the Commissioners. In Dewsbury the vaccinated cases showed 8-2 per cent, of the confluent type, while 6cr2 per cent, among the](https://iiif.wellcomecollection.org/image/b3055696x_0024.jp2/full/800%2C/0/default.jpg)
