Researchers in the Philadelphia area are joining in the quest to stop the spread of HIV. Currently, they are working to develop new vaccines that will prevent individuals from becoming infected. Researchers also hope to develop a vaccine that will be effective in treating those who are already HIV-positive.
There are two types of HIV vaccines. Therapeutic HIV vaccines are treatment vaccines and help treat people who are HIV-positive. Preventative HIV vaccines are designed to prevent people from becoming infected.
According to Hildegund C.J. Ertl, an immunologist at The Wistar Institute in Philadelphia, vaccines are developed through a series of trials. The vaccines are tested first in animals to ensure that they create a safe immune response. So far, Ertl’s research has produced strong results.
“Our vectors induce strong T-cell responses in mice and monkeys even if the animals have pre-existing antibodies to human serotype adenoviruses,” Ertl said.
Once the vaccine proves to be immunogenic in animals, they test it for contaminants before beginning trials on human subjects. First, they conduct a dose escalation trial to determine a safe and effective dose. Then they conduct a second trial in which they combine two different vaccines sequentially.
These experimental vaccines do not contain the real virus. However, some trials have been known to produce antibodies in a persons body that help fight against HIV. Though these antibodies could cause a person to test positive for HIV, it does not mean they actually have it.
Ertl and her team are currently preparing to test a new vaccine. Though she expects the research to have positive results, not all trials make it. According to an article in the Philadelphia Inquirer, Merck & Co. Inc. recently pulled the plug on a trial that was three years in the making because “it didn’t seem to be working.”
This trial was designed to see if the vaccine would prevent HIV infection and also see if it would reduce the effects in those who were already infected.
It failed, but according to Ian Frank, the director of the HIV Vaccine Trials at the University of Pennsylvania, that particular trial may still be useful.
“The information is going to help us develop vaccine in the future,” Frank told the Inquirer. “We’re really at the very earliest stages in this process.”
According to the same article, $759 million is being spent each year on vaccine trials. Thus far, there has been significant advancement in the development of these vaccines but challenges still remain. The greatest of these is how to develop a vaccine for a virus that mutates rapidly and is different in each person.
“That’s the main challenge,” Ertl said. “It’s the reason we can’t readily make vaccines that protect.”