HealthDay News — Drinking water before vaccination does not prevent presyncope in adolescents after vaccination, according to a study published online October 23 in Pediatrics.
Alex R. Kemper, MD, MPH, from Nationwide Children’s Hospital in Columbus, Ohio, and colleagues conducted a randomized trial involving individuals aged 11 to 21 years receiving 1 or more intramuscular vaccines in primary care clinics. Intervention subjects (n=901) were encouraged to drink 500mL of water, with vaccination recommended 10 to 60 minutes later, while controls (n=906) received usual care. During the first 20 minutes after vaccination, presyncope symptoms were assessed with a 12-item survey. Symptoms were classified with a primary cutoff sensitive for presyncope and a secondary, more restrictive cutoff requiring greater symptoms.
The researchers found that according to the primary and restrictive definitions, presyncope occurred in 36.2% and 8% of subjects, respectively. For the primary or restrictive outcome, there were no significant differences in presyncope by intervention group. There was no reduction in presyncope for the primary or restrictive outcome among intervention subjects vaccinated within 10 to 60 minutes after drinking all 500 mL of water. In multivariable analysis, presyncope was correlated with younger age, history of passing out or nearly passing out after an injection or blood draw, anxiety before vaccination, receiving more than one injected vaccine, and greater post-vaccination pain.
“Drinking water before vaccination did not prevent post-vaccination presyncope,” the authors write. “Predictors of post-vaccination presyncope suggest opportunities for presyncope and syncope prevention interventions.”
Several authors disclosed financial ties to the pharmaceutical industry.