Next-generation immunotherapies already in development could address some of the problems of earlier vaccines. For example, not everyone makes enough antibodies against drug vaccines to effectively block the high, and a determined addict could probably overcome the vaccine by taking large amounts of the drug. So some scientists are creating antibodies in the lab and then selecting only the most potent to be directly injected into the patient, a strategy known as passive vaccination.

Owens is creating such vaccines for PCP and methamphetamine. Rather than triggering antibody production in the person being vaccinated, antibodies are made in an animal and then converted into a form that can be injected into humans. Owens has started a biotech company, Intervexion Therapeutics, to commercialize his vaccines, and he aims to start tests for a PCP vaccine within the next year, with tests of a methamphetamine vaccine a year after that.

The passive-vaccination approach is costly--making and refining these vaccines is an expensive process--but it offers other advantages. Owens's methamphetamine vaccine, for example, can also bind to other types of amphetamines and ecstasy, potentially giving patients a three-in-one anti-addiction punch. It could also be used to treat overdose by mopping up excess drugs in the system, says Frank Vocci, director of the pharmacotherapies division at the National Institute of Drug Abuse. Still, he cautions, such vaccines are probably several years away. They may not arrive soon enough for Britney, but perhaps the next wave of pop princesses and beauty queens will benefit.