Post-vaccination syncope is a rare but potentially serious adverse event in adolescents and young adults. Because few data are available regarding post-vaccination syncope, evidence regarding presyncope and syncope after blood donation provides useful insight. Based on studies of blood donors, acute water loading fifteen minutes prior to vaccination with 500 mL of water might reduce the risk of syncope. However, the degree to which hydration attenuates the risk of post-vaccination syncope or presyncope is unknown. Furthermore, little is known about the acceptability of pre-vaccination hydration to adolescents and young adults.~The objective of this study is to conduct a study to evaluate the acceptability and impact of oral hydration to prevent presyncope following vaccination in adolescents and young adults 11 through 21 years of age. The primary objectives are to determine if pre-vaccination hydration decreases the rate of presyncope in adolescents and young adults receiving at least one intra-muscular (IM) vaccine and to determine if pre-vaccination hydration is acceptable to adolescents and young adults.~This is a randomized controlled open-label study in adolescents and young adults receiving at least one IM vaccine. Vaccine administration will be part of routine care and will not be a study procedure. Adolescents and young adults 11- through 21 years of age will be eligible for participation. Minimal subject exclusion criteria will be used to best reflect how pre-vaccination hydration could be used outside of the controlled trial setting. For all primary and secondary objectives, data will be collected before and after vaccination, with data collection to be completed on the day of enrollment.
This is a randomized controlled open-label trial. During the study, adolescents and young adults scheduled to receive at least one intra-muscular (IM) vaccine will receive either oral water hydration in addition to standard care or standard of care alone to evaluate the effect of water hydration on the primary outcome of presyncope. This study will also evaluate the acceptability of pre-vaccination hydration among adolescents and young adults.