15 Feb 2021
Setting it Straight: Virus and vaccine - Part 2
Last week we looked a little at the SARS-CoV-2 virus and at the mRNA BioNTech/Pfizer (BP) and the Oxford/AstraZeneca (AZ) ChAd9 virus-vectored vaccines that will soon be going into the arms of Australians (#43). In countries where the pandemic is raging, two identical, sequential shots of these vaccines have already been given – generally three to four weeks apart – to large numbers of people. We can be reassured that it all looks good so far, though those who are highly allergic and have to carry an epinephrine-loaded Epipen will likely be directed to the AZ product.
The aim here is to give a bit more detail on what the virus does while drawing a parallel with how these vaccines work. Once the SARS-CoV-2 virion is in the cell, it dissociates to release its ‘bad news’ the viral RNA (#6) into the cytoplasm. The first thing that happens is that the single copy of virus-introduced positive strand (+ve) RNA carrying the 11 SARS-CoV-2 genes is exposed and serves as the template for making a whole bunch of little proteins that are required to make the complementary RNA negative (-ve) strand.