Virus acts in different way
NEW subvariants and reduced uptake of vaccines have experts concerned over a new Covid threat.
Chief medical officer Paul Kelly said rates of reinfections were expected to rise as not enough of the population had received a third booster shot.
He explained that immunity from the first two vaccinations and having previously had the virus was reduced against some subvariants spreading throughout the community.
“We’re now seeing subvariants of Omicron – the latest one known as BA-4 and BA-5, that’s now become the dominant strain in the UK for example, and it is growing particularly on the east coast of Australia,” he said.
“We know that is more transmissible and does have the tendency to escape the immune system, so we will see reinfections over the coming weeks and months unfortunately with that one.”
Deakin University epidemiology Catherine Bennett said with new variants the virus was acting in ways not seen before.
“We are seeing what we feared might happen, particularly the convergence of a troubling flu season after having had a couple of years of respite,” she told Sky News.
“With Covid, we’re also seeing the numbers stay high and that’s partly because Omicron now has that possibility of having reinfection in ways we haven’t seen before, particularly with these new variants.”
Professor Kelly said people were less worried about Covid than they were a year ago, in many cases due to having already had the virus.
With only around 67 per cent of eligible Australians getting a third dose, the government is urging far greater uptake of boosters, particular among younger groups.
Protection from symptomatic Covid with the Omicron variant reduces to just 15 per cent six months after a second dose of Pfizer or Moderna and to zero six months after receiving the Astra Zeneca, according to the Department of Health.
Conversely, two to four weeks after a booster dose of either the Pfizer or Moderna vaccine, effectiveness against symptomatic infection with the Omicron variant increases to around 60 to 75 per cent.
Additionally, a booster dose increases vaccine effectiveness against severe disease to around 95 per cent in all adults.
It also significantly increases effectiveness against death to more than 90 per cent in people aged more than 50 years.
“We now know with Omicron circulating that a third dose is really important,” Professor Kelly said.