IAVI Report - October - November 2001

Dr. Supachai Rerks Ngarm is currently Senior Expert in Preventive Medicine in Thailand's Department of Communicable Diseases, Ministry of Public Health, and a principal investigator of the prime-boost Phase III vaccine trial due to start in 2002 (see article). A pediatrician and epidemiologist trained at universities in Thailand, Singapore, Israel, Canada and Japan, he was chief of outbreak investigation in the epidemiology section of the Ministry (1985-90) and then became the first director of its new AIDS division during the period when Thailand launched its aggressive HIV prevention program. In 1997, he became coordinator of Thailand's polio eradication program, and has also led efforts to improve immunization services.

Before we talk about the upcoming trial, can you give us some background on how Thailand became so pro-active in AIDS prevention, including vaccines, early in its own epidemic--while so many other countries were doing little to stem HIV spread?

Looking back it seems like it was very easy. But at the time, there were many problems convincing people at the highest levels to take action. The pioneer was Dr. Prayura Kunasol, who was in charge of epidemiology at the Ministry of Public Health. The first case of AIDS was recognized in Thailand in 1984, and from that point on, he began trying to persuade key people in government that this new disease posed a great danger to our country. He was the one of the group who set up a country-wide surveillance system, which became the root of our prevention program.

And the early commitment to AIDS vaccines?

This was a natural step for us, since our country has a great deal of field experience testing other vaccines, such as hepatitis B and Japanese encephalitis vaccine. In 1990, the World Health Organization, through Jonathan Mann, was looking for countries that could carry out AIDS vaccine trials. Our Ministry of Health was very responsive to this. That started the process, first with the formation of a working group, chaired by Professor Prasert Thongcharoen to recommend whether Thailand should do this, and then in drafting national guidelines on how to review and conduct trials. Can you describe the approvals process for the upcoming Phase III trial?

We have a 2-step process. First is an informal consideration by the scientific subcommittee on AIDS vaccines. They will review our protocol and then send feedback to us for modifications. If we agree on this, we will resubmit to the subcommittee so they can officially consider the protocol. They can then say that it's approved, or that it's not approved, or needs further changes. Then we modify the protocol according to their recommendations. Probably in parallel to this scientific review, we can submit our proposal to the ethics committee. Has this process begun yet?

Our protocol was reviewed at the Walter Reed [Army Institute of Research] and we have made some modifications. We are now preparing for review by the Thai vaccine subcommittee. Sad to say, at the moment we don't have the new subcommittee, which is still in the process of being re-established.

Will this subcommittee use the same scientific milestones as the US partners for approving the trial?

We have about the same criteria for our decision-making. If it seems that the trial is not going to have any success, the subcommittee will not agree to move ahead. But for us the exact percentage of vaccinees who respond is perhaps not so strict. Because of the epidemic here in Thailand, even a vaccine with 30% efficacy is still useful for us.

But it would be just one element of our prevention efforts. We don't expect that the first vaccines will be 100% effective, that they will be a magic bullet which eliminates the need for other interventions. We see vaccines as a tool which complements other interventions.

Do you worry that a vaccine that is, say, 30% effective might create a false sense of security so that vaccinated people actually increase their risk behavior?

It depends on how you tell people. We will always tell them that they must stay aware and avoid any risk--always. What are the plans for involving local communities in the trial?

We will try by all means, by every approach, to have the community with us. A community advisory board [CAB] will be one thing. We also plan to have sessions where we talk with community leaders, formally and informally, to explain the importance of this trial and what they can do for the program.

Among Thais, especially the senior people--in terms of both age and social standing--respect is very important. If we go to the leaders and ask for their ideas, their interpretation would be that we respect them, and they would be very proud and pleased to help us. This is the way of Thai culture, that youngsters should pay respect to the senior people. We will try to do that.

How will the CABs be set up?

We will probably recommend that every district has its own CAB, and also that the local NGO sits on this board. It will include representatives of the trial participants, as well as other interested parties such as community leaders and people living with HIV.

Do you expect the press to follow the trial closely?

Our intention is to be very open to the press. We are planning some publicity activities, some community involvement activities. We have already held one media education session, and plan to do this kind of informal meeting with national and local media, probably about every two months. Besides these planned sessions, we will encourage journalists to come to us any time if they have questions.

What treatment will be available to volunteers who become infected during the trial?

We have recently made triple drug therapy the national standard, although because of the cost it isn't yet possible to make it widely available. But for the trial, the Walter Reed has committed to funding triple therapy for intercurrent infections. And the Thai government can provide the infrastructure for making treatment available over the long term.

Since Thailand has had such success in reducing HIV spread via heterosexual transmission, future vaccine trials in community cohorts would require much larger numbers of volunteers. Do you think there will be further Phase III trials in Thailand?

This is the most difficult part of our planning. But the decrease in AIDS incidence is a national average. We still can find regions that tend to be high, or at the beginning phase of HIV spread. Incidence is also very high among injecting drug users [IDUs] in Thailand. So I don't think that this will be our last Phase III trial. But I have to admit that the next trial will probably be more difficult than this one. Even this trial, I don't think it will be easy at all. Scaling up to tens of thousands is not easy. Since the trial will have about 16,000 participants, we may need to screen 25-30,000 potential volunteers.

You mentioned the very high infection rate in injecting drug users, which hasn't changed much even as heterosexual transmission rates have come way down in Thailand. How are you tackling this now?

This part of the epidemic, I have to admit, is the most difficult one for us. Needle exchange programs are not acceptable to our society, but very quietly we are working with some local NGOs to test this approach and see if it works.

Previously we thought that the IDU group was just a small fraction of our society, and that at least we had a methadone program in every big city and in big provinces. We used this service as an entry point for people to access HIV prevention information.

But even though we have behavioral studies that help us understand why people share needles, we still couldn't change their behavior. You can buy needles without a prescription here in Thailand, but people don't want to do that because it can probably be used as evidence against them [if they are arrested on drug charges]. To solve this problem we need to work together, not only within the health sector, but with the police department. We have a very long history with them, not only on IDUs, but also sex workers.

Getting back to vaccines, the cohort studies done in southern Thailand as preparation for the Phase III trial found a very high level of willingness to participate among the local people. Why do you think this is so?

I think that our people, especially in the rural areas, realize what a serious problem we have with AIDS, and they are expecting that there should be something to protect them. I think they also want to help society. Vaccines give people a feeling of hope.

As Buddhist people, we try to do good things while we are alive, since this is what the Lord Buddha taught us. I believe that people think this is one of the good things for their life: to help people and to make our generation safe.

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©2001. The IAVI Report.

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