You can alter what the vaccine uptake will be, what you think the effectiveness of the vaccine will be in reducing transmission, and what you think the reproductive rate of the virus will be (ie how infectious it is, being higher for the UK and other variants). And then see what happens to infection rates over the next year, and net health effects (allowing for the negative impacts of lockdowns).
One lesson we draw from the modelling in this tool is that we do need to keep our borders secure and quarantine comprehensive until Phase 2 (adult vaccination) is near complete. Otherwise, especially if the more infectious UK variants get into Australia and gain a foothold, it may not be pretty.
Unsurprisingly, but importantly, getting vaccine coverage as high as possible to make us more resilient to viral incursions matters. Building confidence in, as well as safe speed of, the rollout matters.
We also find that the negative effects of lockdowns on depression, anxiety and self-harm (let alone economic impacts) mean that as vaccine coverage increases we need to pivot from the aggressive elimination approach that served its purpose in New Zealand and Victoria in 2020, and evolve to a more moderate approach.
Down the track – perhaps about July – we will be seriously discussing Phase 3. Which is vaccinating children. The vaccines are not yet approved for children. Children themselves stand to gain less than adults, given COVID-19 is not as serious an illness for them. But we will need wide uptake of vaccination among all ages in the population for us – as a community – to be resilient to opening up our borders. Put another way, herd immunity is unlikely without also vaccinating children. Approval of the vaccine for children and a high uptake by them as well as adults is necessary.
Speaking of herd immunity, many epidemiologists in a global survey this week expressed concern about variants arising that are resistant to vaccines (and also more infectious, like the UK variant). I too am worried about this (just set the reproductive rate high and vaccine effectiveness at reducing infection low on our web-tool and see what happens).
But if such variants arise, it will be more of a setback than a disaster. We will “just” have to keep evolving the vaccines to cover these new variants, making the SARS-CoV-2 virus (variants) and vaccine more like the annual influenza and flu vaccine. Not ideal, but OK.
Professor Tony Blakely is an epidemiologist at the University of Melbourne.