Some people worry about the fact that some vaccines are grown in cell cultures that were originally obtained from human fetuses. Viruses require a living host in which to grow, and vaccine manufacturers prefer human cells because some viruses can only grow in certain cells, and other viruses that occur in animal cells could harm people. Research is currently underway to develop molecular tools that will allow vaccine production without the use of live host cells. Currently, the human cell strains used to produce some vaccines can be maintained for long periods of time in a laboratory setting and can reliably support the growth of viruses that infect humans. Vaccines developed from these strains have been proven safe for humans. Two different strains of human diploid cell cultures made from fetuses have been used extensively for vaccine production for decades. WI-38 came from lung cells from a female fetus of 3-months gestation and MRC-5 was developed from lung cells from a 14-week-old male fetus. Both fetuses were intentionally aborted, but the cellular biologists who made the cell cultures did not induce the abortions. These two cell strains have been growing under laboratory conditions for more than 35 years. These cell cultures have been used to prepare hundreds of millions of doses of vaccines, preventing millions of cases of chicken pox, rubella, rabies, and hepatitis A.
Rubella virus typically causes a mild illness in most children, but it can severely damage the developing fetus of a pregnant woman who becomes infected. The virus that led to the only rubella vaccine available in the United States came from tissues obtained at the time of an abortion performed on a rubella virus-infected mother. The abortion was not conducted in order to isolate the virus, but rather because the mother and the fetus were infected with wild rubella virus that posed a risk of major birth defects. Since that wild strain of rubella virus (known as RA27/3) was isolated, it has been grown in the laboratory, with no need to obtain additional cells from aborted fetuses to sustain the supply of attenuated rubella viruses used to manufacture additional batches of rubella vaccine for the future.
Before widespread use of the rubella vaccine, there were hundreds of thousands of cases of rubella in the United States and more than 800 cases of congenital rubella per year. As a consequence of the rubella epidemic of 1963—1964, it is estimated that there were 20,000 infants born with congenital defects, 6,250 spontaneous abortions and 5,000 induced abortions due to severe birth defects. In 2001, the CDC reported just 3 babies born with congenital rubella syndrome. Thus, the RA27/3 rubella vaccine has prevented many thousands of spontaneous and induced abortions by protecting pregnant women from infection.
I thought that was interesting. So much for worrying about the sanctity of human life and the unborn if you were against vaccines.