Impact of maternally derived immunity on immune responses elicited by piglet early vaccination against the most common pathogens involved in porcine respiratory disease complex

BACKGROUND: Newborn piglets can trigger an elementary immune response, but the acquirement of specific antibodies and/or cellular immunity against pathogens before they get infected post-natally is paramount to preserve their health. This is especially important for the pathogens involved in porcine respiratory disease complex (PRDC) as they are widespread, fairly resistant at environment, and genetically variable; moreover, some of them can cause intrauterine/early life infections. MAIN BODY: Piglet protection can be achieved by either passive transfer of maternal derived immunity (MDI) and/or actively through vaccination. However, vaccinating piglets in the presence of remaining MDI might interfere with vaccine efficacy. Hence, the purpose of this work is to critically review the putative interference that MDI may exert on vaccine efficacy against PRDC pathogens. This knowledge is crucial to design a proper vaccination schedule. CONCLUSION: MDI transferred from sows to offspring could potentially interfere with the development of an active humoral immune response. However, no conclusive interference has been shown regarding performance parameters based on the existing published literature.