UPDATE: This article was updated on 27 July 2021, in response to a query about whether an mRNA vaccine by CureVac uses fetal cell lines in any stage of its development. It does not. This article was previously updated on 2 February 2021 to explain about the use of MRC-5 and HEK 293 cell lines in the design and testing of some vaccines.

By December 2020, there were 78 COVID-19 vaccines in development. Thirteen were in third stage trials, and seven already had limited approval for use. The Pfizer/BioNtech vaccine was the first to be approved for use in the UK on 2 December 2020.

Concerns have been expressed on social media that COVID-19 vaccines are made from aborted fetuses, and some people object to the vaccines on religious and ethical grounds.

Most of the COVID-19 vaccines in development do not use human cell lines in their production. For example, Pfizer and Moderna use mRNA technology. 

An mRNA vaccine is a new type of synthetic vaccine. As Pfizer explains, mRNA vaccines are made from a DNA template in a lab, rather than the traditional method of being made in cells. The vaccine is then synthetically produced. 

The Moderna vaccine is also synthetic. Moderna began by designing a gene sequence on a computer. Damian Garde explains how Chinese scientists, after isolating the virus from patients, posted the genetic sequence for COVID-19 online. Moderna and BioNtech used software to tell them “what chemicals to put together and in what order”.

The COVID-19 vaccine being developed by AstraZeneca in collaboration with Oxford University has generated the most debate. 

In November 2020, it was widely claimed on social media, including this Facebook post with over 160,000 views, that the AstraZeneca vaccine contains MRC-5 cells from lung tissue of a male fetus which was aborted in the 1960s. 

This specific claim has been fact checked by Associated Press, Full Fact, Politifact, Reuters and Snopes and found to be false. However, the MRC-5 cell line was used in the preclinical testing of the AstraZeneca vaccine.

AstraZeneca did use the HEK 293 cell line to manufacture its vaccine (and Pfizer/BioNTech and Moderna in the design of their vaccines). These cells originate from a fetus which was aborted in the Netherlands in 1973. The fetus was aborted legally at the time for other reasons, and not for the purposes of vaccine research. Alex Kasprak at Snopes has summarised the cell line’s origin story, which began with a Canadian scientist’s research into cancer.

Over the decades that followed, these cells have been cloned and replicated, many times. Dr Paul Offit, an immunisation expert from the Children’s Hospital of Philadelphia who sits on the US Food and Drug Administration (FDA) vaccine advisory committee, describes these as “standardized cell lines”. Professor Helen Petousis Harris says the cells used today are “distant descendants” of the original cells. They are from decades-old, long over abortions, and researchers do not use fetal cells from the present day

Why can’t other cells be used? Alex Kasprak explains that this cell line was selected because they are “uniquely capable of rapidly multiplying modified adenoviruses.” In other words, this is the quickest way of making a traditional vaccine. They have been used in both medical research and the production of vaccines including hepatitis A, rubella, chickenpox and rabies. 

It is also important to understand how cells are used. It is common for vaccines to be grown in labs using cultures. Writing in Science, Meredith Wadman describes cell cultures as “miniature ‘factories’” in which the virus is propagated. After the viruses are grown, they are purified and cell culture material is removed. As Professor Helen Petousis Harris explains to AAP FactCheck, no cells of any kind are part of the final vaccine formulation.

The ethics of COVID-19 vaccines

Religiously conservative think tanks such as the Lozier Institute have expressed their opinion that lab sequenced mRNA vaccines, and specifically the Pfizer and Moderna vaccines, do not pose an ethical problem for them, as they are synthetically produced.

Some religious groups and those opposed to abortion have questioned the ethics of making any use of fetal cells in the design or manufacture of vaccines.

The Vatican’s Pontifical Academy for Life issued guidance on vaccines in 2005, reaffirmed in 2017, that in the absence of alternatives, Catholics may receive vaccines using historical fetal cell lines in good conscience. 

A Belfast News Letter article reported on a blog post by Rev. Malcolm Duncan, Pastor of Dundonald Elim Church. He made an ethical argument in favour of vaccination, to save further hardship for others.

In August 2021, DUP MLA, and former health minister, Jim Wells, cited “ethical concerns” regarding the historical development and testing. He claimed that vaccines had historically used “stem cells and tissues from aborted babies”.  He appealed for the German-made CureVac to be made available in the UK. It is the only mRNA vaccine in development that does not use abortion-derived cell lines in any stage of its production. CureVac has completed the final stage of testing (Phase 3) but, at the time the comments were made, it has not yet been approved by the European Medicines Agency or any other official public health agency in the world.


  • No COVID-19 vaccine contains cells from aborted fetuses. 
  • A replica cell line from a fetus aborted in 1973 was used to develop the AstraZeneca/Oxford University vaccine. However, the vaccine itself does not contain fetal cells. 
  • New mRNA vaccines, such as those being developed by Pfizer and Moderna, are synthetic vaccines, sequenced on a computer in a lab, and do not use fetal cell lines in their production.

This article was originally published on 7 December 2020.

FactCheckNI is Northern Ireland’s first and only dedicated independent fact-checking service and a verified signatory to the International Fact-Checking Network’s Code of Principles. You can learn more about about FactCheckNI, our personnel, what our article verdicts mean, and how to submit a claim.