Background: World Health Organization announced vaccine hesitancy among the top 10 threats to global health in 2019. While the number of persons looking for information on health topics on the internet is increasing, information regarding immunization on the internet is often inaccurate and misleading. We aimed to determine the kind of information parents seek on the internet for decision-making regarding immunizations for their children.
Methods: We investigated threads of an internet vaccine forum, where parents can get personalized advice from a vaccine expert, with regard to the types of vaccines and content of the questions. One thousand six hundred twenty consultations (4896 questions) between September 2001 and December 2018 were examined. Of these, 1386, including 4000 questions, were related to immunizations of the user's child. Date of consultation, user gender and country of residence, age of the child; kind of vaccine(s), and topic of the question according to the following categories were analyzed: Vaccination schedule, safety, effectiveness, necessity, vaccine application, serology, exchangeability of different vaccine types and brands, maternally acquired immunity, reimbursement, and vaccine product related.
Results: Most questions concerned infants (47.7%) and regarded measles-component (28.9%) and diphtheria-tetanus-pertussis combination vaccines (25.3%). Parents were mainly interested in vaccination schedule (33.8%), safety (26.6%), and effectiveness (17.8%) of vaccines. Over time, safety-related questions decreased, and effectiveness related questions increased. Disease outbreaks or newly introduced vaccines and vaccinations temporarily raised interest. From 2011 onwards, most questions regarded measles-component vaccines.
Conclusions: Our findings will assist health care professionals and policy makers in preparing targeted information campaigns to address questions and counteract vaccine hesitancy.