Future COVID-19 variants and outbreaks would be best managed by ongoing vaccination and the quicker scaling up of restrictions, according to new research.
University of Melbourne researchers modelled both the health and economic effects of more than 100 different policy responses on a range of possible new outbreaks.
"What we found in general was that having slightly more stringent public health and social measures, or having lower thresholds for increasing restrictions slightly, did perform better on average across these scenarios," lead author Joshua Szanyi said.
The researchers evaluated 104 types of government response, focusing on the stringency of health measures, levels of mask wearing, whether governments provided respirator masks or not, and the type of vaccination coverage.
The policies were all modelled against nine different future COVID-19 scenarios — one with no new major variant of concern, and eight other options with a new variant — from October last year.
It builds on earlier research from the University which has helped shape government responses, including the path out of Melbourne's 2020 lockdown.
Where the modelling differs from previous research from around the world, Dr Szanyi said, is that the economic effects of policies were weighed up against health outcomes such as deaths and hospital capacity. The effects of long COVID were also factored into the model.
The findings were published on Friday in the Lancet Regional Health — Western Pacific journal.
"The results also reinforced the importance of vaccination in the COVID-19 response," Dr Szanyi said.
The research found increasing the number of over-30s boosted would decrease hospitalisations by about 12 per cent and deaths by about 27 per cent.
Vaccination was also found to be a cost-saving measure in all the scenarios.
The report has been released at a time booster rates across Australia have stagnated, with about 72 per cent of the eligible population having received a third dose and about 44 per cent having received a fourth.
The research also found increasing the prevalence of respirator masks during an outbreak, such as N95s, had a small effect on the rate of hospitalisations and deaths.
Dr Szanyi said while there was strong evidence masks help reduce transmission of the virus, increasing their use "after things have gotten out of hand might be leaving things too late".
High number of COVID-related deaths expected in most scenarios
The research focuses on Victoria and looks at the 12 months from October, 2022.
It found that no matter the policy or context, high numbers of infections and deaths were likely, with 4.2 million infections and 8,100 deaths in Victoria projected over a 12-month period on average.
The researchers ranked the responses on four evenly weighted categories — cost effectiveness to the health system, cost effectiveness with a GDP perspective, number of deaths and days exceeding hospital occupancy thresholds.
Overall, the highest-ranking combination was more stringent health measures, two further vaccine doses for the over 30s and the promotion of increased mask-wearing, but not the government provision of respirator masks.
UNSW infectious disease professor James Wood, who was not involved in the research but reviewed the paper for the journal, said the researchers "did a really solid job with the health burden and cost effectiveness" of policies.
"[They] did some nice work around much much long COVID might contribute in terms of those burdens as well," he said.
As a mathematician, Dr Wood said he would have liked to have seen more details in the paper on the agent model used.
But he said the "massive amount of work" that went into the paper played an important role in starting a conversation about how to balance competing interests in the pandemic.
Health measures most important in event of 'more dangerous' variants, author says
The lifting of isolation rules in October marked the end of almost all COVID restrictions across the country and leaders have signalled they are unlikely to return unless there is a dramatic need to bring them back.
UNSW's Dr Wood said at the time the work was originally done, "it was more of an open question as to how much we would intervene further in COVID epidemics with non-vaccine, non-antiviral type interventions".
"I do think that the population moved on a lot in the time frame from the middle of last year to the end of last year in terms of their willingness to accept that kind of thing," he said.
"But if a bad variant, something worse, showed up again, then you do want to know what the trade offs are in terms of costs and so on."
Report author Dr Szanyi said the public health and social measures input to the model were not necessarily lockdowns, but at some levels were things like working from home.
But he said the models showed the importance of increasing health measures "if we were unlucky enough to get a virus or variant that comes along that's more virulent than Omicron".
"Even when we took into account economic consequences of those decisions, we really saw the value of increasing public health and social measures in those particular contexts," he said.
Last year was the first in which the strain dominant at the start of the year — Omicron — remained the most common 12 months later.
In Victoria, for instance, department of health data released on Friday shows "the recombinant strain XBF makes up the highest proportion of detections, followed by BQ.1/BQ.1.1, and BR.2".
The department said "a group of variants that cannot be classified due to new mutations" made up 17 per cent of wastewater detections.
"While at the moment, we are dealing with Omicron sub-variants, there's no guarantee that the virus won't evolve to be more virulent and more dangerous and have a greater ability to cause severe disease," Dr Szanyi said.
"So I think it's important that people are aware of that fact, in order to have realistic expectations about what might be around the corner.
"We hope that's not the case. But there's no guarantee that it won't be."
