Yael, i am sorry to hear little N is not doing so well.

I am typing this from "The Vaccine Book" Dr Bob Sears.

" How is the Varicella vaccine made? The virus was taken from an infected individual decades ago and placed in the culture of lung cells from human embryos. The virus used the lung cells to mutilply. The viruses were then removed and placed in a culture od guinea pig embryo cells for further growth. Finally, they were put in a culture of human diploid cells (a high-tech engineered group of laboratory cells) ......... to multiply even more. These viruses were then taken to Merk's laboratories.
Merck keeps the virus replicating in a different human diploid cell culture nourished with serum from cow fetus (the liquid part of the cow fetus's blood) and removes batches of virus to go into the vaccine. The viruses are put into a solution of saline, electrolytes, MSG and gelatin. The virus is whole and living when injected, so it can potentially cause chicken pox."

Paraphrasing a bit now....

Ingredients in the final solution;

The live virus
Sucrose
Saline solution
Gelatin
MSG
Potassium (an electrolyte)
Residual components of the Merck human diploid cells
EDTA
Neomycin
Trace quantities of the cow fetus serum.

Standard side effects occur at about an average rate compared with other vaccines.

There is a little more info in the book. But i think that is the main info you are after?

Hope you have some answers soon.

ETA- It also says taking vitamin A and C before and after this shot is thought to be beneficial, just as it is for most shots.