Question Number: 168
PDR Number: SQ22-000146
Date Submitted: 24/02/2022
Department or Body: Department of Health
195.
The COVID-19 mRNA vaccines are designed to make human cells produce the SARS-CoV-2 spike protein and thus trigger human immune systems to create antibodies and specific T cells against SARS-CoV-2 virus. The mRNA and spike protein are quickly degraded and removed via normal cellular processing mechanisms as occurs for endogenous mRNA and proteins.
Animal toxicity studies were conducted on the mRNA vaccines and reviewed in detail by the Therapeutic Goods Administration (TGA) specialist toxicologists before approval for human use. After up to four doses of the vaccines were administered there was no evidence of damage to the immune system (including from microscopic evaluation of tissues of the immune system). Repeated booster doses of the mRNA vaccines are unlikely to cause long term damage to the immune system.
196.
See response provided to question 195 for toxicity testing carried out using animal studies.
No regulatory submissions have been received by the TGA on the impact of receiving multiple booster doses.
The TGA has provisionally approved one booster dose of the Moderna (Spikevax) and AstraZeneca (Vaxzevria) COVID-19 vaccines for individuals aged 18 years and older, and the Pfizer (Comirnaty) COVID-19 vaccine in individuals aged 16 years and older.
The safety and efficacy of these booster doses were demonstrated in clinical studies, in which individuals who had previously completed their two-dose series were given one booster dose only.
Additional or booster doses beyond this are not approved by the TGA.