Researchers at The University of Houston believe they have the biggest weapon ever to fight against it — in the form of a vaccine. Unfortunately, in this population, they relapse at very high rates 80 to 90%," says Dr. Haile. However, Dr. Haile hopes the anti-fentanyl vaccine will shatter those numbers. Now many parents are reaching out to Dr. Haile for their at-risk children, hoping to sign them up for human clinical trials. Dr. Haile also hopes the FDA will quickly approve the anti-fentanyl vaccine, but it still requires years of clinical trials and could be available in about three years.