A review of certain present aspects of smallpox prevention in relation particularly to the Vaccination Acts, 1867-1907.

Date:
1931
Catalogue details

Licence: Public Domain Mark

Credit: A review of certain present aspects of smallpox prevention in relation particularly to the Vaccination Acts, 1867-1907. Source: Wellcome Collection.

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    tact with a ship’s steward who had the same kind of rash on his arrival at Sydney on a ship from Vancouver. The epidemic spread widely but with low infectivity in the State of New South Wales ; by the end of the year 1,073 cases had been notified. It continued, but with a declining incidence, until the end of 1917. The total number of notifications was 2,400 with four fatal cases, of which, however, only one was considered to be a case in which smallpox was more than a contributory cause of the death. In New Zealand the first case was a missionary from Utah who had joined the ship at Vancouver and landed at Auckland on 8th April, 1913. The disease spread in the family with whom he stayed and from them to the Maoris and white population in the North Island. It persisted until April, 1914, by which time it was estimated that 114 Europeans had been attacked, with no death, and 1,778 Maoris, with 55 deaths. Examples of countries in the third category, in which there is persistence side by side of a non-virulent and a virulent strain, are England, Brazil (where the recognition of the existence of two separate strains, one causing a high mortality, the other almost none, dates from 1910) and some of the Southern States of North America, which, already affected with the prevalent benign type, are also liable to frequent importation of the virulent type prevailing in Mexico. Among 6,369 cases of smallpox notified in some of these States between 1915 and 1928 there were 1,509 deaths, a case- fatality of 23-7 per cent., as compared with the case-fatality figure of 0-13 per cent. calculated for other States in which only the non- virulent type prevails. Sometimes in the United States, as in England, it has been possible to trace the carrier of an imported virulent strain of infection and all the resulting cases, thus bringing to light the remarkable difference of toxicity between the foreign and the local endemic strain. At Detroit, for example, where between 1915 and 1923 the benign type was endemic (4,631 cases with only 17 deaths) the importation of a virulent case in January, 1924, was the cause of 163 deaths before the epidemic was got under control by the vaccination of over half a million people within a month. Similar epidemics due to importation from Mexico caused 17 deaths among 119 cases at Los Angeles in 1912, 49 deaths among 191 cases at El Paso (Texas) in 1914, and 20 deaths among 59 cases at Washington in 1925. In considering smallpox epidemics in terms of case fatalities, it must be remembered that often many cases with a considerable degree of vaccinal protection have been included in the totals on which the deaths are calculated. True contrasts of case fatality for this purpose ought to be limited to unvaccinated cases and unvaccinated deaths, but these are rarely separately obtainable for statistical pur- poses. The combined figures, however, suffice to bring out the difference. An example is the occurrence of variola minor in Switzerland between 1921 and 1926, which closely resembled the present variola minor in England.