Figures & data
The ability of a vaccine to induce primary immune responses has relatively little effect on its effectiveness as the primary immune response will have largely abated by the time the pathogen infects the host. This is illustrated by the symmetrical nature of the schematic above and below the dashed line. In the absence of immune memory there is no protection irrespective of the type of pathogen. In the presence of immune memory there is always protection when the pathogen has little immunomodulatory ability. By contrast, protection against highly immunomodulatory pathogens is dependent on the presence of resilient immune memory responses.
