Smallpox deaths by age in England and Wales 1847-1887

Following Edward Jenner's development of the smallpox vaccine in 1796, the death rate due to smallpox in England and Wales dropped significantly. Although Jenner's work was published in 1797, it would take over half a century for the British government to make vaccination compulsory for all infants. Between 1847 and 1853, when vaccination was optional, children under the age of five years had, by far, the largest number of deaths; the total death rate was 1.6 thousand deaths per million people, which was more than five times the overall death rate due to smallpox. When compulsory vaccination was introduced, this helped bring the smallpox death rate in this age group down by over fifty percent between 1854 and 1871. When compulsory vaccination was enforced with penalties in the wake of the Great Pandemic of the 1870s, the smallpox death rate among children under the age of five dropped to approximately fifteen percent of its optional vaccination level.

Increase among adults

Along with the youngest age group, children aged five to ten years also saw their death rates decrease by roughly two thirds, and the death rate among those aged ten to 15 declined by just under one third during this time. It was among adults, aged above 15 years, where the introduction of mandatory vaccination had an adverse effect on their death rates; increasing by fifty percent among young adults, and almost doubling among those aged 25 to 45. The reason for this was because, contrary to Jenner's theory, vaccination did not guarantee lifelong protection, and immunization gradually wore off making vaccinated people susceptible to the virus again in adulthood. There was some decline in the smallpox death rates among adults throughout the 1870s and 1880s, as revaccination became more common, and the enforced vaccination of children prevented smallpox from spreading as rapidly as in the pre-vaccination era.

Overall trends

While the introduction of mandatory vaccination saw the number of smallpox deaths increase for age groups above 15 years, the overall rate among all ages decreased, due to the huge drop in deaths among infants and children. The smallpox death rate dropped by over one quarter when compulsory vaccination was introduced, and it then fell to just over one third of it's optional-vaccination level when these measures were enforced. The development of the smallpox vaccine and the implementation of mandatory vaccination led to the eradication of the disease in Britain by 1934, and contributed greatly to the demographic developments of the twentieth century, such as the declines in fertility rate and birth rate, and the increase in life expectancy.