New Burnet Institute modelling shows that until Australia achieves extremely high rates of vaccination coverage, public health restrictions are essential to provide effective options for control of COVID-19 in the community.
Key findings of Burnet's COVASIM modelling of long-term control strategies include:
- Even with high vaccine coverage thousands of deaths could occur if public health responses are not initiated to help control outbreaks;
- With high vaccine coverage, light restrictions including masks, optional working from home and density limits are likely to be sufficient to control outbreaks, whereas heavier restrictions such as additional restrictions on home visitors would gain control faster. When harder responses were used, less time was spent on average under restrictions;
- If infections are continually introduced into the community, such as with eased international quarantine, then restrictions will either need to be maintained or periodically re-imposed
Burnet Institute Head of Modelling and Biostatistics, Dr Nick Scott said that while vaccines offer Australia more flexibility to control COVID, they're not the silver bullet that will allow us to dispense with restrictions altogether.
"As we open the borders, it's inevitable that some cases will get into the community, and the modelling shows that we would need exceptionally high vaccine coverage to achieve a level of community protection that will stop outbreaks from taking off and causing significant harm," Dr Scott said.
"It may take much longer than we would like to achieve that coverage, or we may not get there at all, which is why we will need to supplement vaccination with some additional control measures.
"But the good news is that the higher the vaccine coverage we can get, the less stringent the additional control measures can be. Rather than relying on lockdowns, it is more likely that light restrictions will get the job done."
Burnet Institute Deputy Director and leading infectious diseases and public health specialist, Professor Margaret Hellard AM said the primary goal for all Australians is to get vaccinated.
"We need to achieve high levels of vaccination across the community to stop large outbreaks that cause significant illness and death. Even with high vaccination coverage a strong public health response is needed to help maintain control," Professor Hellard said.
"It is also important to understand that infection and illness can occur among people who are not yet vaccinated, people who cannot have a vaccine for health reasons and, critically, among vaccinated people, because of imperfect protection against infection.
"In certain scenarios, COVASIM shows up to 45 percent of COVID-19 deaths may be among vaccinated people for whom the vaccine did not work, particularly the elderly. Hence it is important the virus is kept in check, even if not at zero.
"This is a whole of population issue, not just an issue for people who are not vaccinated, which means we need high rates of coverage, and we need to achieve them as quickly as possible to keep the community safe."
Professor Hellard said community engagement is vital to ensure all people understand the benefits of vaccination to themselves, their family and the community.
"We need to ensure messaging is clear and that community leaders, including from culturally and linguistically diverse communities are involved in developing these messages and information for their communities," she said, "and where necessary we need to provide support to help people access vaccines."
