No Need for Aborted Fetal Tissue to Study Zika Nor to Make Zika Vaccine

Another clear example of the lack of need for freshly aborted fetal tissue in virus and vaccine studies are the recent reports on the susceptibility of developing human brain cells to Zika virus.

Scientists from Florida State, Emory, and Johns Hopkins developed a successful model system to show that the Zika virus can infect and damage some developing brain cells.[1] The established experimental model, which the authors of the paper note can now be used for further investigations of developing brain as well as screening therapeutic compounds, was not developed using fetal tissue.

The successful system uses human induced pluripotent stem cells (iPS cells); these iPS cells are ethically created from skin or other normal cell types, and earned the 2012 Nobel Prize for Dr. Shinya Yamanaka, their originator.

Another recent study by a Brazilian group confirms the susceptibility of developing human brain cells to Zika virus infection, with potential damage to infected brain cells. Again, the successful study did not use human fetal tissue, but rather human iPS cells.[2]

No current vaccines are made using fresh aborted fetal tissue. A few vaccines are made using old cell lines that were derived from two abortions; the cell lines were created in the 1960’s and 1970’s (the cell lines are called WI-38 and MRC-5).

Fresh aborted fetal tissue has not been used to make vaccines for decades. Reliance on aborted fetal cells is an antiquated science. In addition, the CDC and other leading medical authorities have noted since 2001 that “No new fetal tissue is needed to produce cell lines to make these vaccines, now or in the future.”[3]

Modern vaccine development does not rely on fetal tissue or human fetal cell lines. Another example of this is the recent success of a field test of a vaccine against Dengue virus, a close relative of Zika.[4] The vaccine provided 100% protection,[5] but was developed using monkey cells and a mosquito cell line.[6]


[1] Tang H et al., Zika Virus Infects Human Cortical Neural Progenitors and Attenuates Their Growth, Cell Stem Cell 18, 2016; in press, doi: 10.1016/j.stem.2016.02.016

[2] Garcez PP et al., Zika virus impairs growth in human neurospheres and brain organoids, PeerJ Preprints 4:e1817v3; doi: 10.7287/peerj.preprints.1817v3

[3] See, e.g., “Vaccine Ingredients – Fetal Tissues,” The Children’s Hospital of Philadelphia, 2014; accessed July 21, 2015 at; CDC quote originally accessed July 2015 at:

[4] Kirkpatrick BD et al., The live attenuated dengue vaccine TV003 elicits complete protection against dengue in a human challenge model, Sci. Transl. Med. 8, 330ra36, 2016.

[5] Check Hayden E, Dengue vaccine aces trailblazing trial, Nature, 16 March 2016, doi: 10.1038/nature.2016.19576

[6] Men R et al., Dengue Type 4 Virus Mutants Containing Deletions in the 39 Noncoding Region of the RNA Genome: Analysis of Growth Restriction in Cell Culture and Altered Viremia Pattern and Immunogenicity in Rhesus Monkeys, J. Virology 70, 3930, 1996; and Medina F et al., Dengue Virus: Isolation, Propagation, Quantification, and Storage, Current Protocols in Microbiology 15D.2.1-15D.2.24, November 2012

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