Online Vaccine Information in a Knowledge Exchange Social Website (KESW)

Background: The potential for misinformation on usercontrolled Knowledge Exchange Social Websites (KESWs) is concerning since it can actively influence Internet users’ knowledge, attitudes, and behaviors related to childhood vaccinations. Objective: The present study examines the accuracy and predictors of health information posted to a Knowledge Exchange Social Website (KESW). Methods: A sample of 480 answers to childhood vaccination questions were retrieved and rated for accuracy. Multiple logistic regression modeling was used to examine whether answer characteristics (best answer, professional background, statistical information, source disclosure, online link, word count, vaccine stance, and tone) predict accuracy. Results: Overall, only 56.2% of the posted answers were rated as “accurate.” Accuracy varied by topics with between 52.8% - 64.3% being rated as accurate. When Yahoo Answers’ “best answers” were examined, only 49.2% rated as accurate compared to 57.7% of all other answers, a finding attributed to widespread nominations of vaccine misinformation as “best answers” for questions addressing the side effects of vaccines. For all other types of questions, “best answers” were more likely to be accurate. Regression modeling revealed that discussions of personal choices regarding childhood vaccinations predicted the accuracy of posted answers, with those who mentioned vaccinating their own children proving more likely to communicate accurate vaccine information, and those expressing vaccine hesitancy proving more likely to share factually inaccurate statements about vaccines. Conclusion: The high prevalence of misinformation on KESWs suggests that these websites may serve as a vector for spreading vaccine misperceptions. Further research is needed to assess the impact of various KESWs and to develop effective, coordinated responses by public health agencies.

Two-sex logistic model for human papillomavirus and optimal vaccine

We formulate a two-gender susceptible-infectious-susceptible(SIS)model to search for optimal childhood and catch-up vaccines over a 20-year period.The optimal vaccines should minimize the cost of Human Papillomavirus(HPV)disease in random logistically growing population.We find the basic reproduction number Ro for the model and use it to describe the local-asymptotic stability of the disease-free equilibrium(DPE).We estimate the solution of the model to show the role of vaccine in reducing Rq and controlling the disease.We formulate some optimal control problems to find the optimal vaccines needed to control HPV under limited resources.The optimal vaccines needed to keep R_(0)≤1 are the catch-up vaccine rates of 0.004 and 0.005 for females and males,respectively;100%is needed to reduce R_(0)to its minimum value.To reduce the expenses for HPV disease and its vaccines,we need 100%childhood vaccines(both genders)for the first 13-14 years and then gradually reduce the vaccine to reach 0%at year 20.For adults(both genders),we need maximum rates(one)for the first 9 years,then 0.2 for the next 3-4 years before reducing gradually to zero rate at year 20.Although the childhood vaccines provide very early protection strategy against HPV,its time to control HPV is longer than that for adult vaccines.Thus,full adults’only vaccines for enough period is a viable choice to control HPV at minimal cost and short time.