Smallpox death rate in Britain's army and navy 1847-1899

According to Edward J. Edwardes, it was in the armies of Europe where the importance of revaccination was discovered. In the pre-vaccination era, smallpox was not a serious problem in the army, as the majority of recruits had already contracted the virus during their childhood and had therefore developed an immunity to it. In the decades that followed widespread vaccination, army doctors began to notice that many servicemen were contracting smallpox in adulthood; the reason for this was that vaccination in infancy did not guarantee lifelong immunity from the virus, and the protection would wear off in adulthood. With this discovery, armies in Europe began to revaccinate all recruits upon entering the army.

Britain slow to adopt revaccination

When compared with the German states in the first half of the nineteenth century, Britain was much slower in adopting compulsory vaccination. The same was true in the army, as the German states began revaccinating all new recruits when the problem was first realized in the 1830s, whereas Britain did not introduce mandatory revaccination in the army until 1858. Although only Home Army figures are available in this time, we can see that the smallpox trends of the eighteenth century were repeating in the British Army, with waves of the disease coming at regular intervals. After 1858, the smallpox death rate decreases considerably in the Home Army, except during the Great Pandemic of the 1870s, and there were little-to-no deaths in the final years of the 1800s.

Even slower progress in the navy and abroad

While the Home Army brought its smallpox death rate down considerably by revaccinating all recruits, the impact was not as strongly felt in the Royal Navy, nor by the British Forces in India. Revaccination also applied to these armies, however their environments did not allow for the change to take hold as quickly; this was due to the nature of the navy, where recruits lived in close quarters with limited sanitation methods, and the fact that smallpox was a serious and endemic problem throughout the Indian subcontinent until the 1970s. The smallpox death rate in the British Navy was brought down considerably by the end of the century. Data suggests that the disease was likely also in decline among soldiers in India.