1 February 2021

In order to be approved for use in the UK, vaccines must meet the strict standards of safety, quality and effectiveness set out by the independent Medicines and Healthcare products Regulatory Agency. Any COVID-19 vaccine that is approved must go through the same clinical trials and safety checks as all other licensed medicines.

Vaccines that are approved will have been through three phases of clinical trials. In Phase 1 and Phase 2 trials, vaccines are tested on small numbers of volunteers to check they are safe and to determine the optimum dose. In Phase 3 trials they are tested in thousands of people to see how effective they are. The group that receives the vaccine and a control group that receives a placebo (either saline or a different vaccine) are closely monitored for any adverse reactions or side-effects. Safety monitoring continues after a vaccine has been approved for use.

Conventional vaccines contain inactivated versions of whatever pathogen causes the disease, or the proteins on its surface, triggering an immune response in the body that enables it to fight the real infection subsequently.

Two of the COVID-19 vaccines that have recently been approved for use in the UK were developed using a novel technology that uses RNA. RNA vaccines are also being developed for the treatment of cancer. The approved RNA vaccines are made by Pfizer-BioNTech and Moderna: 43,500 people were involved in the Pfizer-BioNTech trial and 30,000 in the Moderna trial. Safety was closely monitored throughout and there were no serious side-effects.

So far, several million people have now been given a COVID-19 vaccine with very few reports of significant side effects, such as allergic reactions.

A posting on Facebook made the following false claim: 'The COVID vaccine is an RNA vaccine. This will actually change your DNA.'

RNA is an acronym for ribonucleic acid, a nucleic acid. RNA is physically different from DNA: DNA contains two intercoiled strands (a double helix), whereas RNA only contains one single strand. RNA also contains two different bases from DNA – its chemical constituents are different.

The main function of RNA is to carry instructions about the amino acid sequences needed to make proteins from the genes (made of DNA) in the cell nucleus to the cytoplasm, where the proteins are assembled on structures called ribosomes. This communication takes place by messenger RNA (mRNA), which translates the sequence of base pairs in the relevant part of the DNA into a corresponding sequence of the amino acids that will join up to form proteins in a process called translation.

RNA vaccines, such as those made by Pfizer-BioNTech and Moderna, contain synthetic mRNA, which codes for a protein specific to the coronavirus's surface. The body uses this mRNA to build its own copies of these proteins to which the immune system then responds by producing antibodies. This gives the immunised person protection if they are exposed to the real virus later – in this case, SARS-CoV-2, the virus which leads to COVID-19.

RNA vaccines are not made with viral particles or inactivated virus, so they are non-infectious. RNA does not integrate itself into the host genome (DNA) and the RNA strand in the vaccine is degraded once the protein has been made. The introduction of mRNA into human cells does not change the DNA of these cells and if these cells replicate, the mRNA would not be incorporated into the new cells' genetic information.

In addition to the advantages of safety, clinical trials show that RNA vaccines generate a reliable immune response and are well-tolerated. Furthermore, RNA vaccines can be produced cheaply and rapidly and can be adjusted easily, if necessary, to accommodate any future significant mutations that may occur in the virus. RNA vaccines are also faster and cheaper to produce than traditional vaccines.

COVID-19 has caused over two million deaths around the world and caused many more people to suffer long term harm to their health, while no-one has died or even experienced a serious adverse event following vaccination. If we are to escape from the terrible pandemic, which has now reached almost every country in the world, it is essential that people have confidence in the safe and effective vaccines that have been developed at such remarkable speed without cutting any corners.

People who spread false rumours raising concerns about their safety are not only being irresponsible, but they also risk endangering the lives of others. We are incredibly lucky that scientists have developed vaccines that are both safe and significantly more effective than older vaccines (for example flu vaccines) and it is imperative that, once they are available, as many people as possible accept them.

The author works in a COVID-19 vaccination centre and has had one dose of the Pfizer BioNTech vaccine.



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