Vaccines are made from dead (inactivated) or modified (attenuated live) whole microbes, or from inactivated or recombinant parts of microbes that are responsible for disease (such as toxins or surface proteins).

Although it can take a long time to produce vaccines, they are not difficult to produce. It is the extensive testing required to ensure there are no unintended consequences from them that takes time. The challenge of producing and rolling out vaccines across the population depends on the technical, ethical and regulatory hurdles to overcome.