Introduction

This paper looks at the demographic history of smallpox in the Netherlands in the 18th and 19th centuries. It examines the claim that smallpox vaccination was a prime-mover in the European mortality decline starting about 1800 (Razzell 1977; Mercer 1990; Aaby 1991; Sköld 1996). In the Netherlands smallpox mortality dropped in an unprecedented way from the early 19th century. Largescale vaccination campaigns, launched by Louis- Napoleon, King of Holland, and continued by the new-founded Kingdom of the Netherlands, are considered responsible for the decline of smallpox. At the same time a significant acceleration in Dutch population growth was observed (Hofstee 1978). A similar coincidence has been observed in many other European countries as well (Mercer 1990). Until recently, the impact of smallpox on Dutch mortality levels has never been established with certitude. Was smallpox really a major check upon Dutch population growth?

Smallpox in the ‘Randstad’ area

Since the 17th century the ‘Randstad’ (the urban agglomeration of the Western Netherlands) was very densely populated, allowing crowd diseases like smallpox easy circulation. In the 18th century smallpox epidemics were very frequent in major Dutch cities like Amsterdam, Rotterdam, the Hague and Utrecht, with recurring outbreaks every three years. Smallpox had a noticeable destabilizing effect on the number of deaths, especially in childhood (Table 1).

In epidemic years, urban mortality commonly increased 25 to 30 %, and occasionally 40 to 50 %. However, few smallpox epidemics generated a mortality crisis as defined by the French demographer Jacques Dupâquier (1979: 248-250). Dupâquier's Index equals (D-M)/σ, where D is the number of deaths in the calendar year concerned, M is the mean number of deaths during the ten preceding calendar years, and σ the standard deviation of deaths during the same ten years. A scale is used, which goes in geometric progression from a magnitude of 1 for a minor crisis (index values > 1 ≤ 2) to one of 6 for a catastrophe (index values exceeding 32). During the one hundred years, from 1710 to 1809, each of the cities Amsterdam, Rotterdam and Utrecht suffered a genuine mortality crisis on fifteen occasions (appendix 1). Only five of these were generated by smallpox epidemics, though in others smallpox made an additional contribution to surplus mortality.