SuperCourse is a repository of lectures and research methods materials on global health and other areas of science designed to improve the teaching of prevention and increase number of scientific publications. Supercourse has a network of about 2 million scientists in 174 countries (together with BA African Networks) who are sharing for free a library of about 200,000 lectures in 33 languages.
Online classes to strengthen the technical, managerial, and leadership competence of the current public health workforce and to advance the knowledge and skills of the future public health workforce. Training topic areas center on competency-based, practice-focused courses addressing core functions and essential services: Environmental health; Potable water, Solid & hazardous waste; Air quality; and more.
MIT OpenCourseWare (OCW) is a web-based publication of virtually all Massachusetts Institute of Technology course content, undergraduate and graduate: over 2300 courses in over 30 departments have been added to the site. OCW is open and available to the world.
Add the word "lecture" to your search to help narrow the results to academic and scientific lecures on your topic of interest. You can also browse the YouTube "channels" of reputable institutions, such as UC Berkeley, WHO, and others.