This review is about the development and use of vaccines from the early smallpox vaccine in the 18th century to the forthcoming SARS-CoV 2 vaccines. Immunisations have been of paramount importance for childhood mortality and public health in general, but some obstacles have also been encountered such as vaccine failures and vaccine scepticism. This calls for continued emphasis on large phase three studies not only for demonstration of efficacy but also for safety and possible side effects. The rapid approval of SARS-CoV 2 vaccines requires special attention.