By Dr Kathryn Mainstone, NCWQ Health Adviser
Vaccines for COVID-19 – Australia can afford to wait
Current vaccines are highly unlikely to be the silver bullet in the COVID-19 battle. We will have to wait until the end of 2020 to start looking at the results of Phase 3 trials, which look into the effectiveness of these vaccines.
There are currently approximately eleven vaccines, mRNA and protein-based or viral-vector based, which are undergoing Phase 3 trials all over the world. In addition, there are five vaccines in Russia and China undergoing larger “mass vaccination” trials. Once a vaccine has reached the stage of showing safety and triggering an immunogenic ie T-cell and an antibody response, they can then go on to a Phase 3 trial. It is vital that people understand the difference between immunogenicity and efficacy – a vaccine may show immunogenicity but still not reach the real-life efficacy standard. Vaccines that are efficacious may reduce mortality. The current influenza vaccination is only 50% effective but hospitalization and death are reduced.
What we need to be cognisant of is that these Phase 3 studies are only being done in healthy 18-55 year olds. Very few studies have been done in the very old or very young. We will not know whether they in fact require a higher dose to be effective or how safe giving a higher dose may be. This is because vaccinations usually take 5 to 10 years to be brought to market and there has been a rush to produce a vaccine for COVID-19 in record time, for obvious reasons. Of note is that the Australian Government is prioritizing giving the early vaccination to the elderly population when there has not been a trial done on its effectiveness in this age group. We will know more about the results of these trials before the end of the year and may adjust our decision making according.
Pandemics usually last about four years and result in three to five waves. Australia has done extraordinarily well in crushing our pandemic risk, through closing our borders and listening to our scientists. We need to remain vigilant, continue to be tested and to stay home from work if unwell. Australia can still have an outbreak if we become complacent.
Vaccinations are likely to improve in efficacy as time goes by. Australia has time to be guarded in its response to vaccination because vaccination will not change our daily lives, even if it is taken up widely. The best response to a pandemic still remains the time-honoured course of quarantine, test and trace, washing hands and physical distancing. Vaccination will be helpful but it is only part of the answer.
David Lim ( Host ). ( 2020, 2nd October). Race to a Vaccine – A vaccine may not be a game-changer.
( Episode 127 ) ( Audio podcast episode ) in Healthed Going Viral