Developing a vaccine for AIDS

Developing a vaccine for AIDS

Creating a vaccine to counter the Acquired Immunodeficiency Syndrome (AIDS) is akin to chasing the holy grail of medicine. Some success was at hand last week when a seven-year vaccine trial in Thailand showed that a vaccine reduced the risk of contracting the disease by one-third in a trial involving 16,395 persons.

The Thai trials, conducted by the US army and the Thai government, involved giving the vaccine to 8,197 persons and 8,198 persons were given a placebo or treatment with no preventive effect. Of those given the vaccine, only 51 were infected, while 74 persons were infected in the group that received placebos. The difference, while it is significant, is not beyond error. As a result, more work is needed. But it marks a first in an unequal battle and is a much-needed sign of hope.

The virus that causes AIDS, the human immunodeficiency virus (HIV), comes in many forms (called subtypes), something that makes it very difficult to create one vaccine that can curb all the strains of the virus. That is only one problem. HIV is a virus that evolves at a rapid rate: As a result, at any given time the infected person may be host to viruses that differ in their genetic make-up. Thus to say that a person is infected with “a" virus is to state matters loosely. To make matters worse, different strains of the virus recombine to create hybrids, and infection by such hybrids further complicates the problem.

Thus the Thai trials should not be cause for false joy: The trials were based on the subtypes B and E and not the C strain that is common in India and elsewhere. The sad fact is that HIV vaccine discovery is an expensive proposition, well beyond the means of poor nations. Pharmaceutical multinational companies that have dedicated research and development (R&D) facilities are likely to be more interested in recovering their R&D costs and are not philanthropic organizations. The situation sounds almost like a conspiracy between nature and political divisions: There are at least eight strains that are distributed geographically and that too among poor African and other developing nations. It will be a while before an effective HIV vaccine/vaccines become available.

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