The Doherty Report will be familiar to anyone who has been following the news updates about the Delta outbreak. However, Australia's political leaders differ on the interpretations of the epidemiological modeling.
It is worth looking at what this important work does and does not say, given the political fight that has erupted between the different levels of government. Let's not get bogged down in the what. Instead, let us start with the why.
Why are governments at war?
This dispute is a reflection of the position Australia reached in the pandemic. Increasing vaccination rates will allow governments the opportunity to relax stringent public health restrictions. We can't eradicate the coronavirus and it is a serious illness that affects many people. Therefore, restrictions must be removed. There are risks of rising infections, serious illness, hospitalisations, and even death. Some leaders of state and territory have expressed concern about the fact that we are opening up to young people while many are not vaccinated. Scott Morrison is determined to make a difference. On Monday, he declared that the current Groundhog Day must end. He said it would end when 70 to 80% of the adult population had been vaccinated. However, the decision to decide when and how to live with Covid ultimately comes down to what level of infection and death Australians are willing to accept. It's hard. It is because of this that there are many differences.
What is the Doherty Report?
The Doherty Institute was requested to prepare a report that would be submitted to the national cabinet for consideration at the end July. It considers the impact of different vaccination rates on the transmission of the virus in different communities. The model also examines the level of social and public health measures required to manage the outbreaks. This is the most recent version of the work that was updated on the 10th August. The report's main scenarios estimate how fast and far an outbreak of 30 people would spread throughout Australia at the transition to phase B (which is when 70% is vaccinated). More research is being done to determine if higher numbers of cases will change the conclusions. We will be discussing this in detail shortly.
Is the Doherty model able to show vaccination rates of 70% and 80% for freedom days?
Two words.
Absolutely not.
What does it mean?
Doherty's work suggests that Australia's ability to overcome restrictions without serious adverse consequences is dependent on two variables. The first is how many people have been vaccinated, and in which order. The second is whether state health systems can effectively test, trace and isolate new infections (TTIQ).
What happens to lockdowns?
It all depends. Doherty states that TTIQ may only be partially effective in an outbreak due to pressure on the public healthcare system. In such cases, light or moderate restrictions might not be enough to regain control of epidemics. According to Doherty, prolonged lockdowns are likely to be necessary in order limit the number of cases and infection rates. If TTIQ is successful, it will be a different story. If TTIQ is still highly effective, then it's possible to keep an eye on outbreaks when 70% are vaccinated. This can be done by imposing moderate public health interventions such as capacity restrictions for public spaces and lockdowns that are less severe than strict. Low public health measures, such as capacity restrictions and not lockdowns, may be enough to maintain 80% coverage if TTIQ is still highly effective. If TTIQ is unable to keep up, public health interventions will need to increase, although likely with a limited lockdown.
These conclusions could be changed if there are more cases.
Although it may be marginally, Doherty believes that higher numbers of cases is unlikely to significantly change current landing points. Threety cases is quite a different reality from our current reality. However, the Doherty simulations of an epidemic show that it can happen. The simulations show that even with 70% or 80% vaccine rates, an epidemic could spread to 30 people, until new infections reach 35,000 to 55,000 per day. A bushfire is a type of epidemic. It burns until the fuel runs out. However, if the TTIQ is effective at high vaccination rates infections spread less quickly.
Do you think the Doherty model is the best?
No. Treasury has provided a separate assessment of economic costs associated to restrictions. Two conclusions can be drawn from Treasury's assessment. The first is that it is much more cost-effective to manage the Delta variant through a strategy to minimize cases and optimize TTIQ rather than allowing greater community transmission. This leads us to a world of public health restrictions, though likely without lockdowns. Second, the Treasury insight is that deploying tight local lockdowns to respond to outbreaks is much more cost-effective than imposing more prolonged lockdowns.
What do Treasury think about 70% and 80%?
If 70% of adults, that is people over 16, have been vaccinated, Treasury anticipates that outbreaks will be contained with only low-level restrictions. Lockdowns are unlikely to be required (there are many qualifiers). Treasury believes that low-level restrictions are the best way to reduce cases at vaccination rates below 70%. This is without having to resort to more expensive lockdowns. Treasury predicts that this strategy will have a lower economic impact if it is used at higher vaccination rates (above 80%). Although Treasury acknowledges that it hasn't modeled the economic impact of a serious and widespread outbreak that threatens Australia's health system, Treasury points out that the expected economic consequences are very high.
Who is telling the truth? Scott Morrison or the premier?
While the prime minister doesn't lie about Doherty's fate, he is moving people quickly past the nuances that are really important. Morrison encourages people to be focused on the positive aspects of life after lockdowns and not get bogged down by footnotes. This is understandable considering that prolonged restrictions can have a serious mental health impact. There is also political brinkmanship, which is the most obvious. Morrison wants to play a blame-game. The prime minister wants frustrated citizens to take responsibility for the failure of the country to reopen after we have reached 70% vaccination rates. Some premiers, the people in charge of health systems that are vulnerable, ran ahead of the prime minster last week to highlight the risks and identify the crossroads Australia was at. What number of hospitalisations can Australians tolerate? How many serious illnesses can you take? How many people die each year? How many children die?
