[Evaluation of reproductive and developmental toxicity: its importance in the preclinical phase of new vaccines].

Preclinical trials in laboratory animals, particularly those aimed at evaluating potential effects on reproduction and offspring development, have gained importance in recent years due to the development of new drugs and vaccines intended for both children and individuals of reproductive age. The current challenge lies in the need for reliable and rapidly obtainable data to enable the transition of new compounds to clinical phases and eventual approval. Since pregnant and breastfeeding women are often excluded from clinical vaccine trials, including those assessing toxicity, there is limited knowledge about this vulnerable population and their offspring. In this context, preclinical studies designed to assess the effects of vaccine and therapeutic candidates on reproduction and development must rely on in vivo models that accurately replicate key aspects of the pathogenesis observed in human disease. When evaluating the reproductive toxicity of vaccines, it is essential not only to assess potential effects on fertility, embryogenesis, development, and reproduction, but also to consider the interactions of the vaccine with the immune system of both the mother and her offspring. This review updates and describes preclinical studies in laboratory animals for new vaccines, particularly those developed against COVID-19, highlighting published studies on reproductive and developmental toxicity, as well as the current regulatory framework governing such studies.