The two last days were filled with news about the latest large scale vaccine trials against HIV. Here’s a simple Q&A

What was the news ?
The news was that the latest HIV large scale trial of a vaccine showed that the vaccinated group had a reduced rate of 31% of infection versus the control group. The trial took place in Thailand.

What vaccine was this ?
The trial used two vaccines (ALVACR HIV and AIDSVAXR B/E) that were matched to the strain of HIV that is predominant in Thailand (Clade E). The study had hypothesized that the vaccine would reduce HIV acquisition by 50 percent. The study results were statistically significant, although they did not reach the level that had been specified as the rate of infection was reduced by 31%.

How large was the trial?
This is a big study with 16,000 adults enrolled since 2003. Budget was solid too as the US government put up 105 million dollars for the study.
The study recruited adults in the community in two provinces of Thailand with high HIV prevalence (Chon Buri and Rayong), but did not specifically target individuals at high risk of HIV infection. Volunteers for the study were adults aged 18-30. It was a randomized trial, matched for sex, behavior, age.
Out of the 16,000 adults, half got the vaccine and half got the placebo. The study started in 2003 the Volunteers were tested for AIDS for 3 years. The results were only ready just 3 weeks ago (beginning of September 09)

What should we make of the success ?
First it should be understood that the result was a surprise. After all the two strands of vaccine used were both proved to be inefficient.
The effect is modest but it’s a stepping stone. It open up doors to identify what the exact mechanisms of this protection is. Scientists now will have to identify what has protected these people in order to try to amplify that effect in future test.

Is it ethical to conduct HIV tests on people that will practice unprotected sex ? Isn’t it better to teach them to have protected sex?
Actually, in vaccine trials huge as these, all participants and everyone who gets the vaccine are intensively counseled on how to avoid being infected. It makes the vaccine trial more difficult but training is a very important part of the aid program. The training is conducted by special counselors completely dissociated from the scientists.

Why is it so hard to make a vaccine against HIV?
The virus has been discovered in 1981. It has been in the history of science the most challenging virus to tackle because of its specificity:
a) The immune response of the body is far less than for any other virus, it has been branded ‘inadequate’. Only about 2% of infected people have developed natural immunity read here

b) The ability of HIV to establish latency, allowing it to “hide” in host cells and elude immune surveillance

c) The extraordinary diversity and mutability of the virus; the capacity of the virus to avoid a protective immune response by masking more conserved components of the virus; and the ability of HIV to destroy or cause the dysfunction of critical immune system cells.

Hope
There are several other vaccine candidates in the research pipeline and today’s encouraging results will provide renewed enthusiasm for human clinical trials, as well as additional HIV vaccine discovery.

Excellent reading
Preventing HIV – the seach of an HIV vaccine

This is the big news of today : Two potentially key genes linked to the development of Alzheimer’s disease have been uncovered by UK researchers.

Zdnet reported today the story of Robert Goldman, the story of a software engineer, who invented a medical device that could save the lives of countless terminally ill cancer patients.

Mr Goldman developed a feeder vessel that can directly deliver chemotherapy treatment to cancer cells. His idea was to create a catheter small enough so you could pass it through the blood vessels and go as close as possible to the tumour to deliver treatment . His research was motivated by efforts to try and save his sister which diagnosed with terminal cancer.  It’s a fantastic story of his stubbornness to try and succeed in an area he knew absolutely nothing about, and with experts that told him it couldn’t be done.

Best of all he then created his company and the device has just been approved by the FDA

The bbc website today reported that two new antibodies that neutralise the HIV virus have been discovered.This is an important find because antibodies are one of the most natural way to treat a virus.

Before this finding only four antibodies to HIV had been discovered that were widely agreed to be broadly neutralising. However, all four worked by binding to a place on HIV that has proven difficult for vaccine-makers to exploit

The latest duo are potentially much more useful because they bind to the virus at sites which scientists believe are more accessible.

Keith Alcorn, of the HIV information service NAM, said: “Identifying antibodies that act against a broad range of HIV types will be critical for the development of an effective vaccine.
“We need to remember that this is an early stage of research.
“HIV vaccine research will be a long-term effort and we certainly shouldn’t expect these findings to lead to a vaccine in a few years.
“A lot more work on antibodies and vaccine design is going to be needed to come up with vaccines that can be put into clinical trials.”
The IAVI team joined forces with the Scripps Research Institute, and the biotechnology companies Theraclone Sciences and Monogram Biosciences on the project.