The plot about vampireblood being mistaken for a drug causing a vampire infestation is pretty much taken from Frosbite, a film which ironicly is inspired by the original The Lost Boys.
The prologe sequence is a homage to the opening scene of Frostbite and both films use of nazi vampires. Also, the shots of blood splatting in the snow is a direct homage.
When Beckert walks into the patients room we just see his shadow at first and he appears to carry a hammer and a stake. It turns out to be flowers spoofing Nosferatu