HIV Hopes Ride on Therapeutic Vaccine
May 19, 2005
At an Emory University conference starting today in Atlanta, scientists will discuss efforts to develop a therapeutic HIV vaccine. Since researchers so far have been unable to concoct a preventive HIV vaccine, a new focus is a vaccine that might boost the immune response of HIV-positive patients.
Experts say people with HIV might accept a higher risk of vaccine side effects. A vaccine that could even partially stem the progress of the disease could require only a few doses, and it might allow patients to stop taking costly antiretrovirals.
Merck is testing a new vaccine this year in several locations including Emory's Hope Clinic. The vaccine uses an inactivated adenovirus to deliver scraps of HIV to the body's immune system so it will recognize and attack the full-scale virus.
Some therapeutic vaccines are beginning to show promise. Last November, French researchers reported on 18 HIV-positive Brazilians who received an individually tailored therapeutic vaccine. Four months later, the patients' virus level had dropped an average of 80 percent. The French researchers will speak at the Emory conference, held through Friday and attended by about 150 scientists.
A different therapeutic vaccine by another French group, and another recently studied in US patients, also showed some benefit.
The challenge for scientists working on vaccines is to activate both the body's killer cells and its antibodies. Researchers have identified five rare HIV patients with naturally developed HIV antibodies. The key is to figure out how they were generated, said Dr. Seth Berkley of the International AIDS Vaccine Initiative.
Dr. Frances Priddy, medical director of the Hope Clinic, said although no HIV vaccine is expected to be approved for years, therapeutic vaccines, which can carry slightly more risk than preventive vaccines, might be available first.
05.19.2005; David Wahlberg
This article was provided by CDC National Prevention Information Network. It is a part of the publication CDC HIV/Hepatitis/STD/TB Prevention News Update.