Australia’s independent expert advisory group on vaccines is meeting to discuss fourth Covid-19 booster doses, as Omicron subvariants drive a rise in infections, leading some premiers to urge people to wear masks more widely.
The BA.4 and BA.5 strains of Omicron are becoming the dominant strains of Covid-19 in Australia, overtaking the BA.2 strain. A preliminary analysis estimates BA.4 and BA.5 to be about 36% more infectious than BA.2. This infectiousness is driving a new wave of disease, however, there is no indication the variants are more severe.
While Covid-19 vaccines do protect well against severe disease and death from the variants, they do not appear to be as effective at stopping infection and symptoms when it comes to the BA.4 and BA.5 strains.
The Australian Technical Advisory Group on Immunisation (Atagi), which advises the federal government about the national vaccination program, will need to factor in many issues: growing community cases, waning immunity from vaccination, a mix of immunity from vaccination and infection, the development of new, more targeted vaccines and when these may be available, and the ability of BA.4 and BA.5 to evade existing vaccines, as they consider whether to recommend widespread rollout of a fourth dose.
Health minister Mark Butler said he would be surprised if eligibility for fourth doses was expanded to the whole population.
“Maybe Atagi doesn’t make any change or maybe it simply reduces the age threshold down to something like 50 or 55 as we’ve seen in some other countries,” he said.
“I’d be surprised if there was a full scale addition to the entire population, but we’ll wait and see what their decision is.”
The Victorian premier, Daniel Andrews, said on Tuesday his government would follow any Atagi advice regarding a fourth dose for the general population.
He added Atagi would have to balance the case for an immediate fourth dose for healthcare workers or wait for a more targeted top-up shot that could better protect against the new subvariants.
“That’s not an easy decision to make,” he said. “I’m very confident Atagi takes these matters very seriously,” he said.
In late June, the federal department of health said healthcare workers would not be routinely offered a fourth booster dose, citing Atagi advice that there is insufficient evidence for such a move. Three vaccine doses, especially when combined with prior infection, offers good protection against severe disease, hospitalisation and death, Atagi found.
A fourth booster dose is already recommended for people at increased risk, including older people, people with medical conditions that increases the risk of severe illness, and people with disability with significant or complex health needs. Atagi has said it will continue to review its advice and will update it if necessary.
Atagi have also begun reviewing data on the effect of Covid-19 on children aged six months to five years. Currently, there are no vaccines being administered to this age group in Australia.
On Tuesday, NSW health minister, Brad Hazzard, raised concerns about the availability of antivirals, and urged people to get their third booster dose if they had not already, saying 56% (1,232) of Covid-related deaths in NSW this year were in people who have had two or fewer doses.
“We are at the beginning of the third wave of Omicron which is likely to peak in late July or early August,” he said.
The state’s chief health officer, Dr Kerry Chant, urged people to wear a face mask in public indoor spaces, where physical distancing cannot be maintained.
“Unless we pull together as one again, this new wave will hit schools and businesses hard, just like BA.1 did, which saw thousands of workers absent,” she said.
Queensland premier, Annastacia Palaszczuk, said “there are discussions happening about urging people in certain situations to wear masks” as cases rise. But she added that mandates were not being considered.
Meanwhile ACT health minister, Rachel Stephen-Smith, said a fresh mask mandate was not being ruled out. However, she indicated other options may be more appropriate.
“There is a view that mandatory mask requirements might not be as effective as they have been in the past, partly because those people who are willing to wear masks are already doing so,” she said.
“Some of those settings where we’re seeing transmission you wouldn’t be required to wear a mask anyway, so all of those things need to be balanced as we move through this winter period.”
Victorian chief health officer, Prof Brett Sutton, said the BA.4 and BA.5 strains had become dominant in Geelong and Melbourne wastewater detections.
“The department of health anticipates the prevalence of BA.4/BA.5 in Victoria is likely to result in an increase in cases – including reinfections – and hospital admissions and deaths,” Prof Sutton said on Monday.
The national Covid death toll is now more than 10,000. Hospitalisations had reached 3,511 across the country on Monday, the highest levels since February, during the height of the Omicron wave. Nearly 30,000 infections were reported nationally on Monday.
Changes to the Biosecurity Act will come into effect on Wednesday, with international arrivals no longer needing to declare their vaccination status to enter the country.
with AAP
