[From popularization to participation: communicating science in the "knowledge society".]

Vaccines are among the scientific topics that draw most interest in the public sphere. The discussion, however, can produce polarization, eventually becoming a controversy between "supporters of science" and "antiscience people". The aggressiveness of some anti-vaxxers, and their resistance to scientific evidence, can induce the belief that the confrontation is worthless, because many think that the top-down approach is the only one that can be used. The premise of this approach is that the gap of information is the main barrier between the scientific community and the society. However, from the '80s to date, studies have shown the fallacy of some assumptions of the so-called "deficit model", including the claim that the communication of science can be reduced only to dissemination and popularization of scientific facts. Studies and experiences, even in public health communications about vaccines, have highlighted the relevance of public engagement, social context, values systems, "lay knowledge" and the complexity of the relationship between science and society, fostering the emergence of new communication models. In the "knowledge society" we need effective communication to all, because people make use of scientific facts when they are involved in decisions on many public issues. Therefore, an evidence-based assessment of each communication approach and an evaluation of the effectiveness of methods in different contexts are required.