This paper provides a psychological perspective on the possible effect of the Internet on the decision against vaccination. The reported importance of the Internet in health decisions is still low, but rising; especially the amount of interactive use of the Internet is increasing, e.g. due to the use of social media. It is argued that the fact that individuals do not report the Internet to be an important source of information does not necessarily mean that the information obtained in their Internet searches is not influential in their decisions. Evidence is summarised here regarding the (anti-)vaccination information on the Internet, and its influence on risk perceptions and on vaccination intentions and behaviour in relation to the encoded information. The conclusion suggests that scholars should strive to explain the underlying processes and potential mediators of vaccination decisions to increase the effectiveness of health communication. In reference to a definition of evidence-based medicine, a great future challenge lies in evidence-based public health communication based on interdisciplinary research involving public health, medical research, communication science and psychology.