The Effects of Attenuated Versus Inactivated Flu Vaccine in Twin Sets

LAIV4 vaccine dosage is 0.2 mL. The vaccine will be administered as an intranasal spray. Each sprayer contains a single dose of FluMist® Quadrivalent; approximately one-half of the contents should be administered into each nostril. 0.1 mL (i.e., half of the dose from a single FluMist sprayer) is administered into each nostril while the recipient is in an upright position. Insert the tip of the sprayer just inside the nose and rapidly depress the plunger until the dose-divider clip stops the plunger. The dose-divider clip is removed from the sprayer to administer the second half of the dose (0.1 mL) into the other nostril.

IIV4 vaccine will be administered as a 0.5 mL dose, with a sterile, disposable syringe and needle by IM injection.