Originally, I was planning on writing a comment in response to Rebellious Pastor's Wife however, if I were to do justice to the topic I need more room.
First, I would like to address the concern of not doing enough research. This may or may not be a fair charge to level on people doing medical research. Why? Simply put, the human body is an extremely complex and diverse "machine," it is simply impossible to test for all circumstances because you cannot predict or know what all the circumstances are going to be. Frequently, what happens is simply a product of the Law of Unintended Consequences. Sometimes this is bad and sometimes it is good. A case in point is a doctor who noticed that fewer women died in the hospital when they were seen right after meals. His investigation turned up the factor involved was that he washed his hands before eating. He tested his findings by washing his hands after each examination and, what do you know, fewer women died. Other times and these are the times they make the news is when it goes bad, such is the possible case with Thimerasol, they used it too prevent contamination by fungi and bacteria, it is very good at this job. Yet, there was no way they could predict that the levels used could possibly be a cause of autism, particularly since autism is still not well understood.
Now some people do have adverse reactions to vaccines. Some can be quite serious, i.e. people died from the old small pox vaccination. Most can be mild i.e. breaking out in hives. The reasons are quite diverse from nurses not paying attention to expiration dates (happened to me with a Tetanus booster) to allergic reactions to the serum. Cases of contracting the disease are exceedingly rare if it is even true that they happen. All of these problems are hard to predict and because of this difficulty you are supposed to wait around for 15 minutes. The worst adverse reactions tend to show during that time frame. Demonstrated adverse effects should constitute reasonable reasons for discontinuing that particular line of vaccination unless it can be demonstrated that it was due to contamination.
Second, do not sell young children's immune systems short. They are incredibly capable and flexible systems and can easily handle the vaccination load. In addition, for vaccines to be remotely responsible for Autism does require a preponderance of variables. The first is that Autism would have to be proven to be an auto-immune disease where the immune system is attacking the central nervous system (CNS). Second, the antigens involved in eliciting the immune response in vaccinations would have to be similar to antigens in the CNS. This is highly unlikely for several reasons. The first is they do not use nerve or brain tissue for the production of any vaccine, which would be the most likely source for the production of these antigens. In addition, the majority of vaccinations given to children are for bacterial toxins which in no way resemble CNS antigens and are very specific. With these in mind I seriously doubt the load of vaccinations is responsible.
Now, my third point is the use of fetal tissue. In reality, this has been blown out of proportion. The use of fetal tissue is limited to vaccines for viruses as bacteria do not require living tissue and when I left the Vet. Microbiology dept for seminary there was work being done on using bacteria to synthesize the viral antigens, because bacteria are cheaper to maintain than tissue cultures. I have a feeling in the next 20 years we will start seeing vaccines made this way and the pharmaceutical companies will buy into it because it will cut their costs significantly. One batch of MRC-5 cells costs over $250 and they have a limited reproductive cycle plus the production of virus destroys the cells, so that adds up very quickly. When you consider bacterial colonies can exist in perpetuity there is no question of cost benefit. Admittedly that is in the future so back to here and now.
All of the viral vaccinations have non-human diploid cell (fetal tissue) alternatives except for Rubella, Varicella (Chicken Pox and Shingles), and Hep A. The alternatives generally use chicken eggs to create the vaccine. They generally work just as well. There are notable exceptions such as Rabies, the HDC Rabies vaccine has a 100% efficacy rate, unusual even for HDC derived viruses, and can be used as a treatment for recently infected patients. Rubella differs from all the other vaccines in that the child that was used for the tissue sample was already infected with the virus due to the mother contracting Rubella while pregnant, which is why it is impossible to find a non-HDC source. The CDC has an excellent resource on their website that lists all of the approved vaccines in the U.S at this link. If you do Google searches of the brand names, the companies have the information posted on how they produce the vaccine and most are available through the John Hopkins link I provided previously.
Now, I did some digging and the pharmaceutical companies all use two HDC lines in producing their vaccines: MRC-5 and WI-38 available through American Type Culture Collection. Both of these cell lines were created from children aborted in the 60's in Europe (WI-38's remains were transported to the U.S.). No new lines are being created. One reason is purely practical the current viral vaccine research needs different cell lines. HIV for instance will only grow in T-cells and both commonly used HDC lines are not immune related. The continued use of these lines falls very close to the debates about the NAZI medical experiments.
The use of the results of NAZI experimentation has caused scientists many ethical dilemmas as illustrated by this 1989 NY Times article. What do we do with what is learned from atrocities committed in the past? There are some who would have us ignore what was learned and try to unlearn what was learned. I can see some of the appeal of this position, because we do not want to be complicit after the fact in their torture and murder. However, I do not take this position. I believe we should keep what was learned and work towards preventing further atrocities. This view forms the basis for my position on the use of HDC's in vaccine production and my advocacy of Pro-Life. One way that we can look at this is that God has worked something good out of something absolutely horrible. I think in someways by throwing out what has been learned would dishonor those who lost their lives. At the same time we can strive to sanctify medical technology (so to speak) by working towards more ethical means of study and production.