Tracey-Ann Wisdom, Gleaner Writer
Duncan
Twenty-five years into the AIDS pandemic and with no cure on the horizon, the world is pinning its hopes for a break-through on the possibility of a HIV vaccine.
The HIV Vaccine Trials Network (HVTN), the world's largest clinical trials programme, has 21 studies in progress or development in parts of the United States, Europe, Africa, South America and the Caribbean. Two of these trials are currently under way in Jamaica at the Epidemiology Research and Training Unit (ERTU) on Slipe Pen Road, in St. Andrew, and co-principal investigator, Dr. Jacqueline Duncan, believes that a vaccine could have the greatest impact upon HIV prevention.
"In 2005, there were 3.9 million new cases of HIV," she said. "This, despite years of prevention work, distributing condoms, telling people you cannot tell by looking, use a condom every time. People still engage in risky behaviour."
Dr. Duncan also pointed out that vaccines have successfully stopped other epidemics, such as polio-myelitis, measles, mumps and rubella.
Leading cause of death in '04
"A vaccine would also delay progression (from HIV to AIDS), which is another concept being looked at. It could also prevent mother-to-child transmission," she said.
Statistics from the Ministry of Health shows that in 2004, HIV/AIDS was the leading cause of death for young men and women aged 15-24 years old in Jamaica, and was a leading cause of death among Jamaica's children as well. There are over 500 children living with HIV, most of them born to HIV-positive mothers. It is also estimated that 25,000 Jamaicans are living with HIV and since 1982, a total of 6,437 AIDS cases have been reported.
According to information on the HVTN website, www.hvtn.org, a preventative vaccine may provide 'sterilising immunity', or total prevention of infection it may not prevent primary infection, but decrease the possibility of transmission from an HIV-positive individual to another person.
Testing of the vaccine
Joy Braham, coordinator of the trial, disclosed that one product being tested is from Merck, a global research-based pharmaceutical company that develops, manufactures and markets vaccines and medicines, and the other is from the research centre of the National Institutes of Health in the United States. One is testing a DNA plasmid vaccine, which uses a small number of copies of HIV genes, which will produce proteins similar to ones from real HIV. This is followed by an adenoviral boost. The other uses an adenovirus vector, which is a weakened cold virus, used to induce an immune response.
Both studies are in Phase II (2), where researchers test the vaccine among hundreds of HIV-negative volunteers and continuously monitor the safety of the treatment and how the body's immune system reacts to the vaccine. One trial involves 3,000 people, 11 of whom are from Jamaica, who will be monitored for approximately five years. The other involves 480 people, 24 from Jamaica.
These vaccines are made of synthetic proteins made to resemble one of the proteins in HIV.
Ms. Braham said Jamaica was chosen as a test site for several reasons, such as the number of people said to be living with HIV in the country, as well as the fact that the vaccine has to be seen to work in different populations and ethnicities around the world.
"We want to see if it would be effective here," she said.
Donna Brown, a 36-year-old mother of three, said she does not know much about the vaccine, butif she were not HIV-positive and ineligible for screening, she would have volunteered.
Sensitising the public
"If they say it would work to prevent (HIV transmission), they can go ahead with it," she said. "I just wonder if Jamaican people will go along with it, like how they are afraid to do a HIV test because they don't want to know their status and they are unable to deal with it."
Ignorance from the general population is not the only problem the trial faces. Ms. Braham pointed out that even some health care workers do not know what the vaccine is about. Consequently, members of the trials staff at the ERTU are working with different groups of health care professionals to sensitise them to the use and make-up of the vaccine.
"I heard a nurse say (that she would not want to be injected with HIV)," Dr. Duncan said. "This is a problem because people might go to a nurse neighbour or a doctor friend and are discouraged from partici-pating in a trial because they don't understand what it is about."
Additionally, there is the fact that HIV continuously mutates and forms new strains of the virus that differ from the original. This makes it hard for scientists to develop a single vaccine that will work across the board. Therefore, a multiclade (or multi-strain) vaccine would have to be developed, Dr. Duncan said.
"We're about 23 years into HIV vaccine research. Jamaica has only been involved three years, so we might have another couple of years of research left," she said. "Each time, the vaccine gets better. We'll participate in trials as much as possible."
In the meantime, a new trial will begin at the end of the summer to assess the effectiveness of one of the vaccines already tested.
Not her real name
