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Coronaviurs, Stefania Di Marco explains the steps of vaccine production Agenzia DIRE



Dr Di Marco, in this emergency that is affecting Italy and other countries, you are leading the team currently working for IRBM on the Coronavirus vaccine. Can you tell us about the stages involved in preparing this vaccine in particular and whether timescales might change given the epidemic that is spreading inexorably.


The vaccine is based on an adenovirus which is duly modified and rendered harmless. Into this adenovirus we insert a piece of DNA that corresponds to the surface protein of the Coronavirus, so we don’t work with the virus but with a piece of synthetic DNA which is inserted into this other virus, which is duly modified and rendered harmless. In fact this is called a “genetic vaccine” because there’s this piece of DNA that is inserted into this other virus which acts as a container, as a container molecule. There are basically two production phases of the vaccine. In the first phase, this vaccine is produced in an in vitro cell system, thus by using a cell system a certain quantity is produced. But then comes a second phase, the purification phase, which harnesses what is known as a “chromatographic medium”. In this module, the aim of the purification is to succeed in removing all possible contaminants from our vaccine. So the aim ultimately is to obtain a pure product. The pure product, and therefore the vaccine which will be produced, must however then be tested. Basically the first test relates to concentration, so we need to find out how many vaccine molecules are present in a specific vial. The second test is a test to determine the potency of the vaccine, i.e. how well does it work in vitro, we’re still talking about in vitro here, in a cell system. Then a series of tests will be carried out to ensure the absence of other contaminants. Once we feel the vaccine is ready and meets quality requirements, then the vaccine can be used in trials, clinical trials on animals. If the epidemic were to continue more quickly, rather than taking a standard path which can be very long, the regulatory authorities might decide to bypass some steps, some parts of the process. For example, animal experimentation could be skipped, because the adenovirus platform that we’re using to produce the vaccine has been widely used to create other vaccines; it has been tested on humans and is known to be safe. Testing could therefore be skipped and this would shorten timescales. The same is true of clinical trials on humans: some phases can be skipped. This does always depend on the regulatory authority however, because its aim is to ensure that the product, i.e. the vaccine that is to be injected into humans, is safe. However, this will all be discussed at the appropriate time, should it be necessary to shorten timescales.

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