A step closer to AIDS vaccine?

City-based NARI's AIDS vaccine found safe after initial results of phase I trials; final results to decide immune response likely in a few months

Is India right up there among the major contenders doing pathbreaking research to develop an AIDS vaccine? If the results of the Phase I trials currently underway for an AIDS vaccine at the city-based National Aids Research Institute (NARI) are any indication, then it could be true.

Preliminary results of Phase I of the AIDS vaccine trials conducted by NARI and Chennai-based Tuberculosis Research Centre have found it to be safe.

This is the first research of its kind in India for the development of a vaccine that would check the spread of the HIV/AIDS epidemic.

Speaking to MiD DAY, Dr Sanjay Mehendale, acting director of NARI, cautioned that while the results were encouraging, the study was an ongoing one and would take many years for completion.

"We started the research in 2004. At that time we tried a single-dose vaccine but the immune response it generated in recipients was too low," said Mehendale. "Next we tried another strategy, and the modified vaccine was tried in Chennai, for which the results were better. However, the immune levels were
still not up to the satisfactory level."

In the next stage, 32 volunteers were enlisted for the study and a two-pronged approach was tried.

"We first gave the recipients a DNA-based vaccine as the prime, and we followed it up with the Modified Vaccine Ankara (MVA) as the boost. In this combination, we have found the results to be satisfactory," he said.

However, while the vaccine has been proved safe, the final results can only be declared after one or two more
follow-ups are done with volunteers and these results are tabulated.

Another scientist from NARI explained that while the prime-boost combination had shown a better immune response in volunteers, the magnitude of the response needs to be tested on a larger population.

"After it is established that this is a good combination, we need to test it on a larger population. The efficacy of a vaccine can only be discussed when the immune response generated by it is seen in a large number of people and is persistent and not sporadic instances," he said.