The death of three monkeys that had been administered an AIDS vaccine in a Boston lab suggests that vaccines intended to prime the immune system to control HIV in the body and prevent disease progression may not offer total protection from AIDS. Numerous HIV vaccines in development aim to boost the body's defenses to hold the virus in check, with animal studies to date suggesting that the protection offered by the vaccines could last for years, if not indefinitely. However, researchers at the 10th annual Conference on Retroviruses and Opportunistic Infections in Boston on Wednesday reported that three of four monkeys involved in such a study at Beth Israel Deaconess Medical Center in Boston eventually fell sick and died, even after initially showing strong resistance to the virus. All three died within three years of receiving the experimental vaccine developed by Merck.
Researchers were split on their opinions of the Merck vaccine data. David Ho, scientific director of the Aaron Diamond AIDS Research Center in New York City, called the data "worrisome." He also noted that because many researchers are facing similar stumbling blocks in their vaccine studies there is a renewed emphasis on creating a vaccine that stimulates an antibody attack to prevent HIV infection, rather than on controlling HIV infection in people who already carry the virus. But Emilio Emini, head of Merck's vaccine program, said other experimental vaccines similar to Merck's could prove to be successful because they use more viral genes that may convey even greater boosts in immune system responses to HIV in the body. "You shouldn't read too much into it," he said of the results from the Beth Israel study.