Fearmongering can have far-reaching consequences.

In 1998, the Measles, Mumps and Rubella (MMR) vaccine was fraudulently linked to autism, resulting in a reduction in vaccine acceptance. This, in turn, resulted in a predictable increase in cases of measles. One of the lessons from this, is what we say - and share - really matters. It isn't too much of a stretch to say the actions of those who spread false information about MMR were incredibly costly. The health and wellbeing of our children was at stake. 

We're over 20 years on from the MMR debate, but as false information about Covid-19 vaccines is spread on social media, we find ourselves in a similarly dangerous situation. And the two stories are linked. For while you should not rely on the MMR vaccine to protect you (you should not!) there are hints it may, for a time, lessen the severity of Covid-19.

Given both my position as an immunologist and ordained minister in the Church of England, I will be highly recommending everyone I know and love says 'yes' to a vaccine once it becomes available. Despite what some have claimed on social media, there is no vaccine against Covid-19 that will make you infertile or genetically modify you.

There have also been concerns that developers may have compromised safety in their rush to develop a vaccine. While that may sound like a valid and understandable fear, it isn't to anyone who has an understanding of how vaccines are developed.

Historically, many vaccines have been produced from viruses or bacteria that have been weakened or killed. Not only can it take time to do this, the developers must be certain that the vaccine itself will not cause disease. This adds yet more time. But the vaccines that have garnered recent attention, from Moderna, Pfizer-BioNTech and Oxford-AstroZeneca, have not taken this approach. Instead, they have taken a small part of the coronavirus and used genetic techniques to enable the immune system to see it. Adopting this approach means that vaccine development can be rapid and, since only a small part of the virus is used in the vaccine, a number of safety concerns are reduced.

Covid-19 vaccine development has also been helped by some research teams preparing for a coronavirus outbreak (since the outbreaks of SARS and MERS in recent years provided some forewarning of the risk), and by developing vaccine technology that can be quickly modified for different diseases. Moderna and Pfizer-BioNTech, for example, have applied their experience in messenger RNA (mRNA) vaccines to Covid-19. mRNA is related to DNA and, within cells, it is the molecule that is directly decoded by cellular machinery as part of the process in the manufacture of proteins. Since it is chemically different to DNA, it is impossible for mRNA to find its way into your chromosomes and cause mutations – one of the reasons it is an attractive molecule for use in vaccines.

Oxford-AstroZeneca took another approach. They used a modified virus, which cannot grow in humans and had previously been used in vaccine development for other diseases, including MERS.

Despite the different approaches, each of these Covid-19 vaccines has been extensively tested prior to clinical trials, and they give every indication that they are safe to use. Sadly, that does not mean that they have escaped controversy.

As has been publicised across various media, the Oxford-AstroZeneca vaccine is produced in tissue culture, using the HEK-293 cell-line, before being purified to remove all the cellular material. The final vaccine, therefore, contains no cells.

The use of HEK-293 cells, nevertheless, has become controversial because they were developed from cells taken from an aborted foetus in the early 1970s. While this abortion was not undertaken to provide material for science, it is inescapable that this is the source of the cell-line. The original embryonic kidney cells were then modified during culture to create the HEK-293 cell-line that is now widely used by biologists all around the world. Indeed HEK-293 cells are so widely used that I have struggled to think of treatments that have not had some contact with them. Thus, while the production of the Pfizer-BioNTech and Moderna vaccines themselves require no cells, HEK-293 cells were nevertheless used during their development.

For many, the origins of this cell line will reopen the debate around the use of knowledge and technology developed from questionable and unethical practices, a debate that is certainly important. However, as we consider our positions around receiving a Covid-19 vaccine, or any other vaccine, perhaps the Vatican Pontifical Council may have the final word: "The burden of this important battle cannot and must not fall on innocent children and on the health situation of the population."

Jocelyn Downey is an immunologist and ordained minister in the Church of England. Following a PhD, he gained experience in immunology research in the US and the UK before undertaking qualifications in theology, and studying issues concerning human uniqueness and personhood. He currently works for an NGO. The views expressed here are his own and do not represent the views of his employer.