Xenotransplantation has the potential to address shortages of organs available for

clinical transplantation, but concerns exist regarding potential risks posed by porcine

microorganisms and parasites (MP) to the health of human recipients. In this study,

a risk-based framework was developed, and expert opinion was elicited to evaluate

porcine MP based on swine exposure and risk to human health. Experts identified 255

MP to include in the risk assessment. These were rated by experts for five criteria

regarding potential swine exposure in the USA and human health risks.MP were subsequently

categorized into three risk mitigation groups according to pre-defined rules:

disqualifying porcineMP(due to their pathogenic potential, n=130); non-disqualifying

porcineMP(still relevant to consider for biosecurity or monitoring efforts, n=40); and

alert/watch list (not reported in the USA orMP not in swine, n=85).Most disqualifying

(n = 126) and non-disqualifying (n = 36) porcine MP can effectively be eliminated with high biosecurity programs. This approach supports surveillance and risk mitigation

strategies for porcine MP in swine produced for xenotransplantation, such as documentation

of freedom from porcine MP, or use of porcine MP screening, monitoring,

or elimination options. To the authors’ knowledge, this is the first effort to comprehensively

identify all relevant porcine MP systematically and transparently evaluate the

risk of infection of both donor animals and immunosuppressed human recipients, and

the potential health impacts for immunosuppressed human recipients from infected

xenotransplantation products from pigs.