The Real Story on a COVID-19 vaccine
This week’s expert: Prof Ian Frazer, Clinical Immunologist; Researcher for Vaccine Development, Faculty of Medicine, The University of QLD.
Drawn from an interview with Clinical Immunologist Prof Ian Frazer by Dr Harry Nespolon on the Healthed podcast Going Viral.
• Based on our knowledge about immunisation against other coronaviruses both in animals and humans, if we do get a vaccine against SARS-CoV-2, it is unlikely to be highly immunogenic or confer long-term immunity.
• The major challenge exists because SARS-CoV-2 affects the respiratory tract, where the immune system is distinct from the rest of the body. Currently the problem is that we are trying to get a vaccine that is delivered systemically to specifically and significantly affect the immune system in the respiratory tract.
• In addition, immunity is limited by how well we can target the particular proteins on the virus, and this SARS-CoV-2 is an envelope virus which means the protein on the surface of the virus is going to change shape.
• Currently there are about 80 vaccine candidates in development around the world with several starting clinical trials. But while a 12-month timeline may be feasible to have a vaccine passing safety and efficacy tests, there will be major issues in manufacturing enough vaccine to immunise the whole population.
• We will need to have 60% of the population to be immune (with either past infection or immunisation) to slow the spread of COVID-19.
• The nature of this type of virus means that immunity tends to wane with time, as with the flu virus. So it is likely that should a vaccine be developed, immunisation will need to be repeated every one to two years.
• It is almost certain that the current SARS-CoV-2 virus will eventually mutate and no longer cause the same disease. However, RNA viruses such as this do not mutate quickly, so waiting for this is unlikely to be helpful in combatting this pandemic.
• It is more likely that effective treatments for COVID-19 disease will be developed before a safe and effective vaccine is available for widespread use.
• COVID-19 is the second pandemic caused by the coronavirus (the first being SARS in 2002). It is very likely that we will get a SARS-CoV-3 and 4 in the future and we need to be prepared.