In 1840, parliament passed the first vaccination act. The 1840 act usually receives only a brief mention in most histories of public health, and most authors see it as a preliminary step toward compulsion. However, it is important legislation in its own right, setting up an effective public vaccination service, which survived virtually unchanged until the end of the century, for the whole population in England and Wales. Under the act, boards of guardians established stations, manned by public vaccinators in every union in the country, where a large proportion of the infant population received vaccination.

The 1840 act is a curious piece of legislation. The bill succeeded where earlier attempts to legislate on vaccination had failed because the political climate had changed: In the intervening period, successive governments had passed many reforms aimed at protecting the lives and interests of the poorer sections of society. Yet it is difficult to fit the 1840 act into wider patterns of social reform. A private member not the government introduced the measure, and parliamentary debates reflected concerns about effective administration, rather than the desire to strike a blow for a more interventionist state. The act was also unusual in that enshrined the views of ordinary medical practitioners. Although a large body of rank-and-file practitioners failed to persuade parliament of the need to allow medical regulation of the new service, they won some concessions over the working conditions for public vaccinators.