Why are there no vaccines for Virus diseases?

In a vaccine, a dead or weakned germ is inserted into the body and that helps in immunization as the body is able to fight it, but in case of diseases like Chicken Pox or AIDS etc, there is no cure, why?? why can't a dead or weakned germ be inserted like any other disease?? how is it different.?

The main reason is from mutation of the strains of the virus. If you were to compare original AIDS virus to those we encounter today, you would find that their biomechanism has changed. Virtually yearly, we have an outbreak of flu but each time, the virus has mutated to the point where vaccines do not work or also like the common cold that has resisted researchers attempting to attenuate it. There are some drugs available for viral infections, most expensive, but most are limited to specific viruses. The best hope we have at the moment is to ameliorate the symptoms and provide whatever life-support is needed. Some virus are self-limited and expend themselves in about two weeks...such as a cold or Chicken Pox but others linger on. There are theories that perhaps only a few strains of virus exist but mutate and cause different diseases. One of the biggest problems in viral research is lack of funding....we spend a lot to make new weapons to kill, but we are selfish about saving lives. At the moment, there are about 20 virus that are of major concern, Ebola, AIDS, SARS, etc and the US is fearful that Iran or Iraq may have stored viable smallpox virus in hidden labs....If this is true and the virus released...the death toll worldwide would be in the hundreds of millions. An outbreak of Spanish Flu in the 1914-16 era killed 16 million people....we are working on answers but they don't happen fast.

There is a chicken pox vaccine now and would you want to be injected with any form of AIDS- dead or weakened?

There ARE vaccines for LOTS of viral illnesses. Chicken pox DOES have a vaccine, as does smallpox, measles, mumps, rubella, and polio.

Viruses generally have to run their course as traditional antibiotics do not work on them, but vaccines can be and have been developed. HIV is a bit harder because it is a retrovirus that actually attacks the body's own defense system. There have been many advances in caring for HIV, but it really does take years, decades, even, for some of these vaccines to make it to human trials and then onto the market.

Actually I got a vaccine against chicken pox 2 months ago... and it worked!
In any case we do not have vaccines against all possible viruses.
With HIV I think one problem is that the virus can mutate and becomes resistant.
I think it is very tricky to find out what parts of a virus can be injected, which will only help you to build anti corps without making you sick.

virus are very clever,they alter there shape and become a different,thats why flu vaccines are different every year