Two embryonic cell lines have been used to develop COVID-19 vaccines: human embryonic kidney cells called HEK 293 and human embryonic retinal cells called PER.C6. The PER.C6 cell line is from an elective abortion in the Netherlands in 1985, and the HEK 293 cell line comes from an undisclosed source (either spontaneous miscarriage or elective abortion) in the Netherlands in about 1972.
Johnson & Johnson used PER.C6 cells in their COVID-19 vaccine development, and the Oxford/AstraZeneca vaccine used HEK 293 cells. CanSino Biologics and Gamaleya Research Institute’s Sputnik V vaccines have also used HEK 293 cells.
Moderna and Pfizer/BioNTech used HEK 293 cells in their proof-of-concept tests to see effectively take up the genetic instructions contained in these vaccines and produce the required spike protein. But human embryonic cell lines were not used to make either company’s final vaccine.
HEK 293 and PER.C6 cell lines have been genetically altered to include the part of the adenovirus instructions that trigger replication of adenoviruses. This allows the production of a large amount of the final vaccination product and allows the removal of the adenoviral replication instructions in the vaccine.