Flublok Quadrivalent is a
vaccine used to treat the
flu. It is a
quadrivalent flu shot, which means that it protects against four flu strains. Flublok Quadrivalent is less popular than comparable drugs. It is covered by most Medicare and insurance plans, but some pharmacy coupons or cash prices may be lower. Get Flublok Quadrivalent for as low as $67.74, which is 24% off the average retail price of $89.71 for the most common version, by using a GoodRx coupon.