Further information on mRNA vaccines :
Messenger RNA (mRNA) is found in all living cells. These strands of genetic code act as chemical intermediaries between the DNA and protein producers. The vaccine is like a cookery recipe, injecting it into your arm is simply giving specific information to your cells and letting them read it. Your cells expertly assemble the tiny part of the Spike protein from ingredients they already have. After this, the immune system quickly goes after the spike protein fragment, learning to build up a defense against the coronavirus, should it ever encounter it.
Because we don’t normally have mRNA encoding Spike protein floating around in our cells, after we tip off our immune system, the mRNA from the vaccine is destroyed by the cell after its ‘instructions’ are read. Experts believe that mRNA isn’t the same as DNA, and it can’t combine with our DNA to change our genetic code. mRNA never even goes into the nucleus, the part of the cell contains all of your own DNA.

Information from U.S. CDC website: ‘Viral vector vaccines use a modified version of a different virus (the vector) to deliver important instructions to our cells. For COVID-19 viral vector vaccines, the vector (not the virus that causes COVID-19, but a different, harmless virus) will enter a cell in our body and then use the cell’s machinery to produce a harmless piece of the virus that causes COVID-19. Scientists began creating viral vectors in the 1970s. Besides being used in vaccines, viral vectors have also been studied for gene therapy, to treat cancer, and for molecular biology research. For decades, hundreds of scientific studies of viral vector vaccines have been done and published around the world. Some vaccines recently used for Ebola outbreaks have used viral vector technology, and a number of studies have focused on viral vector vaccines against other infectious diseases such as Zika, flu, and HIV. Viral vectors cannot cause infection with COVID-19 or with the virus used as the vaccine vector.