Is it possible to get vaccinated against disease like AIDS? Read on to find out why is it is difficult to develop a vaccination against HIV.
As with all viral infections HIV too has a very small armamentarium of drugs against it. Since viruses multiply within living human cells, drugs to act on them, have to damage the human cell as well.
Viruses being extremely small and having a very simple structure, drugs have a few sites to act on (unlike as in bacteria, where they can act on the cell wall, the nucleus, the cytoplasm, the organells etc.) to disable them.
As for the vaccines, they help us fight diseases by acting on the immune system. Unfortunately in AIDS
it is this immune system itself, which is under attack. Secondly, the virus (like the common cold virus) is known to alter its structure when inside the body thereby rendering the vaccine useless. This is so because the vaccine is very specific and only on a fixed and similar structure. Even a minute change renders the vaccine ineffective. Naturally it is difficult to synthesise vaccines against all the structural variations.
Antiretroviral Therapy (Drugs Useful In Aids)
- Drugs 1 to 5 form onegroup
- 6 the 2nd group
- 7 to 9 the 3rdgroup
Different group drugs act at different sites and bydifferent mechanisms thereby killing the virus.
What is nowbeing promoted is a cocktail of drugs from 2 or more differentgroups.
Hurdlesin Development of Vaccine Against HIV
Pioneering HIV scientist Robert Gallo has pointed out factors that are hindering the discovery of vaccines against HIV. He has also made some recommendations that can support the further research. Let us take a look at them.
- HIV is a retrovirus and attempt to develop vaccine against retrovirus has not been carried out in past.
- While developing vaccine it is not possible to know its effects on humans as the immune effects on the animal models may be different from humans.
- It is difficult to find out that the protection can be secured from which immune response, which is one of the major issues.
- It is not possible to have actively replicating (live) HIV or attenuated HIV in its vaccine due to the chances of reactivation.
- The possibility of killed whole virus to work is also very low as it has not worked satisfactorily in the animal studies.
- Killed whole virus can also be risky as one cannot determine if all the viral particles are killed.
- CD8 cellular vaccine is incapable of acting in the early stages of infection. It works in the chronic stage by reducing the viral load. It is not capable of controlling infections transmitted by people who are severely infected.
- CD8 cellular vaccine cannot make body immune against HIV as HIV itself is immune to the CD8 cellular response.
According to the scientist Robert Gallo, the goal which should be chased while developing a vaccine for HIV should be sterilising immunity. The only practical way to achieve this would be to by eliciting neutralising antibodies which are reactive to different HIV strains to a greater extent.
Till today no vaccine has been developed that can help the human body develop immunity against HIV. But, in near future, it is expected that scientists and researchers will surely find a solution. In the meanwhile it is necessary to take all the required precautions so that HIV infection can be kept at bay