The WI-38 and MRC-5 cell lines, derived from two fetuses that were aborted, respectively, in 1962 in Sweden and in 1966 in the United Kingdom, are used to produce the following vaccines, all licensed and marketed in the United States:
- Sanofi-Pasteur’s Imovax rabies vaccine is propagated in MRC-5 cells. When they were introduced in the 1970s, human fetal cell–propagated rabies vaccines
supplanted dangerous and occasionally fatal animal tissue–produced rabies vaccines.
- Merck’s chicken pox and shingles vaccines are propagated in MRC-5 cells; they are produced at a relatively new company plant in North Carolina. The weakened “Oka” virus used in both vaccines was initially attenuated in WI-38 cells.
- Merck’s rubella vaccine—the “R” component in the MMR vaccine given to U.S. infants and preschoolers—is propagated in WI-38 cells on the company’s campus northwest of Philadelphia, Pennsylvania. Merck has shipped nearly 700 million doses of the rubella vaccine since its launch in 1979. Also known as German measles, rubella, like Zika virus, attacks and damages fetuses in the womb.
- Hepatitis A vaccines are marketed in the United States by both Merck and GlaxoSmithKline; both companies propagate their vaccines in MRC-5 cells.
- The polio component of Sanofi Pasteur’s U.S.-marketed Quadracel vaccine (which also protects against diphtheria, pertussis, and tetanus) is propagated in MRC-5 cells.
- The adenovirus vaccine that since 1970 has protected nearly 10 million members of the U.S. military from respiratory infections is propagated using WI-38 cells.
Note: This information was excerpted from the article “Fact-checking Congress’s fetal tissue report” by Meredith Wadman at Sciencemag.org.