Question Number: 253
PDR Number: SQ22-000623
Date Submitted: 21/11/2022
Department or Body: Department of Health
Question 135 A vaccine-induced immune response does not attack and destroy bodys own cells. Instead, the immune response helps protect people from getting sick from infection by the virus. Either mRNA-Lipid Nanoparticles or locally produced spike protein are taken up by antigen-presenting cells, such as dendritic cells. These cells then move to the lymph nodes, where antigen presentation to T cells and interactions of antigen and B cells take place. This leads to the formation of germinal centres, which results in the generation of memory B cells and antibody-producing plasma cells, available at: (https://pubmed.ncbi.nlm.nih.gov/33673048/ and https://pubmed.ncbi.nlm.nih.gov/33477534/). The human body naturally renews its own cells regularly, with billions of cells being renewed every day. Along with millions of other cells, some cells expressing the spike protein may die, but they would be rapidly replaced by new cells without causing harm. Animal toxicity studies at very high vaccine doses showed no adverse effects except for immune response-related findings, such as local inflammation at the injection and hypercellularity of lymphoid tissues. Question 136 In early studies on other mRNA vaccines (not the COVID-19 vaccines) unmodified mRNA can induce the production of type I interferon (IFN-?) mediated by Toll like receptors, with the possibility of launching a cascade response that would lead to the breakdown of the mRNA before it can produce adequate amounts of protein antigen to induce an immune response, available at: (https://pubmed.ncbi.nlm.nih.gov/27506450/). Note that the problem for these early non-COVID vaccines was potential reduction of efficacy rather than a safety problem. Therefore, the mRNA in COVID-19 vaccines was modified to improve translation efficiency of the encoded antigen protein and to lower immunogenicity of unmodified mRNA. Modifications include replacement of uridine with pseudouridine, available at: (https://pubmed.ncbi.nlm.nih.gov/29326426/, https://pubmed.ncbi.nlm.nih.gov/26342664/ and https://pubmed.ncbi.nlm.nih.gov/16111635/). Question 144 The Therapeutic Goods Administration disagrees with the statement made by the Senator because it is not based in science. The spike protein expressed following vaccination is not a pathogen. Low levels of spike protein expressed from vaccine mRNA do not cause toxicity as is shown by both animal studies at very high vaccine doses and in human studies.