He began his career by teaching a chemistry course, developing the theory of latent heat which was recently discovered by Scottish chemist Joseph Black but had yet to be widely disseminated outside Great Britain.

Odier had obtained data from London relating to the number of deaths from smallpox; he recognised an increase but attempted to show that it was not attributable to inoculation.

He admired the health plans of Johann Peter Frank and Oxford University's Radcliffe fellowships and promoted similar ideas to Swiss and French companies and authorities.

[9] In 1789, as secretary of the University of Geneva, Odier applied for the vacant chair of medicine after becoming the medical advisor to bankers who were setting up the annuities he had written about.

One of the so-called Thirty Immortals of Geneva – a group of girls whose longevity was the basis of a large public loan of Louis XVI – was his own daughter.

In 1760, Daniel Bernoulli had already shown that, despite the risks, the earlier practice of variola inoculation would increase life expectancy by three years, but it sparked many debates.

In France, there was continued resistance from the clergy, led by Armand de Roquelaure (commander of the Order of the Holy Spirit, first chaplain to Louis XV and later archbishop of Mechelen).