While wearing well-fitted respirator style masks is still considered the best means to prevent spreading COVID-19 infection – especially during times of low viral circulation – their usefulness is only marginally better when cases spike.
Vaccination remains the principal public health intervention to reduce infection.
“Masking up during large surges is still a good idea for the whole population, and certainly beneficial for vulnerable people, but is also a bit like acting after the horse has bolted,” says Melbourne University’s Dr Joshua Szanyi.
He’s the lead author of a new paper published today in The Lancet Regional Health medical journal, which scrutinised 104 public health policy packages in response to COVID-19.
The researchers found ongoing vaccination programs and a lower threshold for authorities to scale-up their public health measures would be most beneficial to combating future cases, at least in Victoria.
That state reached global infamy when its capital Melbourne became the world’s most ‘locked down’ city in 2021, owing to public isolation policies during the spread of SARS-CoV-2, the virus which causes COVID-19.
While measures that drive mask-wearing and working from home were found to reduce the worst consequences of the pandemic – case numbers, hospitalisations and deaths – they were found in the study to have a greater economic cost.
The modelling conducted by the Population Interventions Unit at Melbourne University found that, instead, a rigorous vaccination schedule was optimal at reducing the negative outcomes of COVID-19, including health system burden.
Vaccinations provided beyond spring 2022 would reduce hospitalisations by 12% and deaths by 17%, they found.
And high levels of vaccination coverage across a population decreased deaths by 15%, and shaved the time spend in stage three public health measures by a fifth.
“If we are unlucky and get another highly virulent variant like Delta, we may need to have a low threshold for introducing some restrictions to protect lives, even when we take into account economic losses,” Szanyi says.
“In our modelling, ongoing rounds of vaccination to all adults 30 years and over, reduced both the disease burden and pressure on health services, and reduced the duration that society retreated to working from home and other control measures.”
Restrictions in place during the first Delta and Omicron waves, including more simple measures such as mask-wearing and social distancing, have been relaxed in Australia.
At present, Australians over the age of thirty are eligible for a fourth COVID-19 vaccine, including new bivalent options.
Other research conducted by an international team from the World Health Organization, also published in The Lancet, found hybrid immunity – the combination of antigens produced by vaccination and infection – provides higher levels of protection for 12 months, compared to uninfected or unvaccinated individuals.
One year after developing hybrid immunity, a person was 42% less likely to be reinfected, and 95% less likely to have severe COVID-19 if they were.