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The head of the Catholic Church, Pope Francis, speaking in March
Photo: Evandro Inetti / dpa
"It is morally acceptable to receive Covid-19 vaccines that were developed or manufactured using cell lines from aborted fetuses," the Vatican announced on Monday.
This raised a number of questions: Why and for which vaccinations are such cell lines used?
Has the church changed its mind because of the corona pandemic?
A brief overview.
Cell lines from aborted fetuses - what?
There are actually several cell lines derived from aborted fetuses that have been used in research for decades.
The WI-38 cell line, for example, comes from a fetus that was aborted in Sweden in 1962.
The MRC-5 cell line, also from a fetus aborted in the 1960s.
The abortions were not for research purposes but for personal reasons.
The terminations were legal.
The cell lines have been used in laboratories for decades, among other things to breed and research viruses in them - because that requires host cells.
Viruses cannot multiply without cells to attack them.
Especially for vaccines that contain inactivated viruses, cells are needed in which the pathogens can be produced on a large scale.
Cell lines are cells of a certain type of tissue that can be preserved and cultured in the laboratory over long periods of time.
They often go back to a single cell.
WI-38 and MRC-5 are so-called fibroblasts, i.e. cells of the connective tissue.
The cells cannot divide and multiply indefinitely in the laboratory, but they only age after 40 to 60 cell divisions; this value is named after the developer of the WI-38 cell lines, Leonard Hayflick, as the Hayflick limit.
But this also means that a few cells can become very, very, very many - and you can still work with these cell lines today and for longer.
Before using human cells, researchers used cells from monkeys.
But these often contained other viruses, which posed a problem for vaccine safety.
You cannot take just any cells either, because viruses cannot multiply well in all of them.
The polio vaccine, launched in 1963, was the first vaccine to be produced using the WI-38 cell line.
Among other things, vaccines against measles, mumps and rubella that were approved in the 1960s also use this cell line.
A few years ago, two researchers - one of them Leonard Hayflick himself - estimated that the vaccines that WI-38 was used in the development or production of have since prevented about 4.5 billion diseases and saved 10.3 million lives.
And what does the Catholic Church say about it?
The Catholic Church has a clear stance on abortion, which is why vaccines that are linked to production or development are a moral issue.
So can believers get vaccinated even though they refuse abortion?
As early as 2005, the Pontifical Academy for Life published moral reflections on these vaccines.
At that time it was primarily about rubella vaccines.
The Church emphasized the importance of developing vaccines without the use of these cell lines.
But if there is no alternative, be it lawful to protect yourself with these vaccines.
Rubella is particularly dangerous during pregnancy; if a pregnant woman is infected, it can lead to malformations or a miscarriage.
The church has not changed its stance on vaccines in the face of the corona pandemic, but is building on these earlier statements when it now writes: If no other vaccinations are available, it is morally acceptable to receive Covid-19 vaccines which have used cells from aborted fetuses to produce or develop.
However, this does not mean that the use of the cell lines is morally approved.
In which Covid-19 vaccines are the cell lines used?
According to a report in "Science", at least five of the Covid-19 vaccines use appropriate cells.
These include the preparation from AstraZeneca and Oxford University, for which the first data from a phase III study are already available.
In four cases, the cells produced adenoviruses, which then serve as vectors for coronavirus proteins during vaccination.
In the fifth case, the cells produced parts of the Sars-CoV-2 spike protein.
The cells only serve as a kind of factory; they are no longer contained in the vaccine itself.
The viruses or proteins are cleaned before they go into the vaccine.
When asked by SPIEGEL, the company did not answer whether such cell lines were used in the development of the Biontech vaccine.
One could "not send a statement in the short time available."
Catholic bishops in the United States, who recently published a statement on the subject, wrote that both Biontech and Moderna did not use these cell lines in the development and production of their vaccines, but that they did use HEK293 cells for a specific test.
Its origin is also linked to an abortion that took place in the 1970s.
The bishops write that although the two vaccines are not completely free of any connection to the "morally reprehensible cell lines", the connection is very distant.
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