RT Journal Article SR Electronic T1 Pro-vaccine messages may be counterproductive among vaccine-hesitant parents JF Evidence Based Medicine JO Evid Based Med FD BMJ Publishing Group Ltd SP 219 OP 219 DO 10.1136/ebmed-2014-110037 VO 19 IS 6 A1 Helen Bedford YR 2014 UL http://ebm.bmj.com/content/19/6/219.abstract AB