21 years later: Is the HIV vaccine around the corner?

Dr-Nelson Musoba, the Acting director of the Uganda AIDS Commission

VACCINE FOR HIV

HEALTH- Twenty-one years ago, Bill Clinton, American president then, said: "It is no longer a question of whether we can develop an AIDS vaccine; it is simply a question of when. And it cannot come a day too soon."

It has been underway for more than 21 years now and still ongoing—research for the HIV vaccine. This year is the 21st anniversary of HIV Vaccine Awareness Day, worldwide.

Dr Francis Kiweewa, the head of research at Makerere University Walter Reed Project in Uganda notes that HIV is one of those viruses that are so stubborn to fight because it mutates so often and this makes it difficult for researchers to come up with exact HIV look-alikes.

"The rate at which it mutates itself to create several sub-types makes it difficult for researchers to get one vaccine that targets all those other sub-types," he says.

According to a communiqué from AVAC, a global advocacy for HIV prevention, currently, research is on for two kinds of vaccines against HIV. The first, a preventive vaccine, which would help make HIV-negative people less likely to get HIV.

"It would teach their immune systems (made up of cells that fight disease) to spot HIV right away if it enters the body. It would prepare disease-fighting cells to stop HIV from spreading so it does not have a chance to take hold," reads the communiqué. No licensed preventive HIV vaccine exists yet.

The second is a therapeutic HIV vaccine. People living with HIV would use it to help make their immune systems stronger and better able to control the virus. This would make them less likely to get sick. It may also help them to stay well without having to take anti-HIV treatment every day (as they do now). Research on therapeutic vaccines may also help in research on how to cure HIV. No therapeutic HIV vaccine has been proven to work yet.

How the vaccine research is conducted
Kiweewa explains that an HIV vaccine is a drug or product that is artificially formed to train the body to be prepared to fend off the virus when it enters the body.

"The products that we use contain manmade proteins or antigens, designed to induce an immune response against the virus in form of antibodies specialized to kill the virus. It is those antibodies that are produced as a result of introducing the vaccine that are measured to see if this vaccine has the potential to protect," he explains.

According to the communiqué from AVAC, the vaccines are first tested on animals. When the researchers are convinced that the vaccine is safe, it is then tried on humans. The trial is done on a few healthy people, and if it turns out safe and causes good immune responses, more people are included. Thousands of people volunteer to participate in these trials.

Kiweewa explains that researchers explain to the volunteers all about the product that is going to be tried on them.

The researcher continues that the vaccine is given to HIV negative individuals so that when they encounter the actual virus, the immune system that was established in their bodies should be able to counter the infection if the vaccine works.

He further gives an example of measles. When one contracts measles, the body responds by producing antibodies (or simply put soldiers) that are specialized in fighting the measles' virus. And when the person cures from measles, the immune system will stay, so that next time when the virus comes, the body is already primed to fight it, so they will not get an infection.

"We are, therefore, using that very natural phenomenon to try to produce a vaccine that works against HIV. But the majority of the vaccine candidates that we have tested up to date give us that immune response, but not strong enough to prevent HIV infection and that is one of the reasons why we do not have a vaccine today," he notes.

Vaccine trials in Uganda

 Dr. Kaleebu

According to Pontiano Kaleebu, the director of Uganda Virus Research Institute, in Uganda, plans are underway for an efficacy trial.

"The largest we are going to conduct is to see if a DNA plus a protein can prevent HIV infection and another in Masaka that will use mosaic and conserved antigens," he says.

Kiweewa says research in Uganda is done with several partners both local and international, but the main partner internationally are the US military HIV research programme under the US Department of Defence, Henry Jackson Foundation, Jensen Pharmaceuticals, GSK pharmaceutical company and NIH/DAIDS.

"Locally, the main partner is the Ministry of Health and its organs, Makerere University School of Public Health, Uganda Virus Research Institute, CPHL, Uganda National Council for Science and Technology," he adds.

Current international trials going on
According to the communiqué from AVAC, two HIV vaccine candidates are now in large trials. One is called HVTN 702 or Uhambo. It will enroll 5,400 South African men and women. Uhambo means "a journey" in Xhosa, one of South Africa's official languages. Atleast 12 strains of HIV exist in the world. HVTN 702 is testing a vaccine designed to prevent clade C, the most common HIV clade in Southern Africa.

A second trial is called HPX2008/HVTN 705 or Imbokodo, the word for "rock" in isiZulu. In a well-known South African proverb, "rock" refers to women's strength and value in their communities. This trial will enroll 2,600 women in five countries across sub-Saharan Africa. In this region, more women than men are getting HIV. The test vaccine in the Imbokodo trial is designed to protect people from more than one strain of HIV.

Challenges
Kiweewa notes that conducting HIV vaccine research is very expensive and as such, no single partner can be able to meet all the resource needs.

"We depend on multiple partners coming together including donors and governments. Fortunately, the global community has prioritised HIV vaccine research and resources have been put together, though still, they are not enough," he explains.

He also notes that misconceptions from the community are a hurdle as well.

"When we talk about HIV vaccine research, people think that we get a virus and give it to someone and we follow them up, which is not true. This can affect community participation," he regrets.

Uganda on course
As the world awaits a vaccine against HIV, Uganda which has about 1.6 million people are living with HIV, is on course to achieve the 90-90-90 HIV global goal.

According to Dr Nelson Musoba, the acting director general of the Uganda Aids Commission, the goal seeks to ensure that by the year 2020, 90% of all people living with HIV know their status, 90% of those diagnosed HIV are on ART therapy and 90% of all people on ART therapy have viral suppression.

Prevention strategies such as medical male circumcision, prevention of mother-to child transmission, treatment as prevention, voluntary counselling and testing, and lately, pre-exposure prophylaxis, a strategy that relies on using drugs that treat HIV to prevent infections, have all collectively been successful in progressively bringing down the number of new HIV infections in Uganda.