Use of fetal tissue in vaccine development
The use of fetal tissue in vaccine development is the practice of researching, developing, and producing vaccines through the use of cultured (laboratory-grown) human fetal cells.[1] The vaccines themselves contain none of the original cells and very slight traces of human DNA.[2]
Most vaccines currently available were developed using cell strains cultured from two fetuses aborted for other purposes in the 1960s.[3] This has led some to oppose vaccination on religious or moral grounds.[1][2] However, vaccine experts and manufacturers state that vaccines do not contain any of the original fetal tissue or cells, that the abortions occurred decades ago and replenishment with new tissue has not occurred. Also, producing a safe vaccine for many diseases requires the use of these cell strains.[2] The Catholic Church, which opposes abortion, has stated that vaccination should not be refused on moral grounds because the public health benefits of vaccination outweigh the historical use of aborted fetal tissue to develop some vaccines.[1][2]
Background
Immortalised cell lines are an important research tool offering a stable medium for experiments. These are derived either from tumors, which have developed resistance to senescence, or, in a few cases, from stem cells taken from aborted fetuses.[4] Fetal cell lines have been used in the manufacture of viruses since 1930s.[5] One of the first medical applications of fetal tissues was their use in the production of the first polio vaccines.[5] For example, in the 1950s, scientists at the Karolinska Institute in Sweden propagated a polio virus in fetal cells to make into a polio vaccine. The resulting vaccine was given to about 2,000 children.[6]
Many other vaccines, including those for chicken pox and rubella, are made using fetal tissue from two pregnancies terminated in the 1960s, for reasons unrelated to vaccine development.[5][7][8] Descendants of the fibroblast cells from these fetuses have been growing in labs ever since, as the WI-38 and MRC-5 cell lines. They are still used to grow vaccine viruses today.[9][1] As of March 2017, at least 300 million vaccines have been given that were made using the WI-38 line alone.[10]
Applications
Vaccines that have been or are made using fetal tissue for the propagation of viruses include:
Adenovirus[11]
Chicken pox[6]
Ebola[12]
Polio[11]
Rabies[11]
Rubella[6]
Shingles[11]
Of these, the vaccines approved for use in the United States include some of those against rabies (Imovax), rubella, chicken pox, shingles, and adenovirus (as of January 2017).[6]
Rubella example
One historical cell line used in rubella vaccines was obtained from a fetus aborted due to infection with rubella.[13] Rubella during pregnancy can lead to miscarriage (spontaneous abortion), and if it does not, there is a risk of severe disability due to congenital rubella syndrome.[14] By one estimate, rubella vaccination may prevent up to 5,000 miscarriages per year in the United States.[2]
https://en.wikipedia.org/wiki/Use_of_fetal_tissue_in_vaccine_development