At 105, May Harrison might just be Australia's oldest COVID-19 survivor.
May recently fended off the virus and this week celebrated her 105th birthday, surrounded by family and friends.
"I was very sick and when I came out of it, I was very weak, but I got over it," she told the ABC.
"We were to have had a bigger [party] on the Sydney Harbour but they didn't think I was strong enough.
"But I love my parties."
May is one of the nearly 46,000 Australian aged care residents who have contracted COVID-19 since the start of the pandemic.
And although the daily press conferences are long gone — and, for many people, life has returned to something much closer to normal — COVID-19 cases in Australia remain at around 45,000 per day.
Experts are warning that COVID-19 still "has tricks up its sleeve" with reinfections rising and new strains emerging.
Aged care under COVID strain
Last week, there were more 780 active outbreaks in aged care facilities and the sector is under pressure.
Whiddon Aged Care runs 20 centres across NSW and Queensland, including the facility where May lives in south-west Sydney.
Its chief executive, Chris Mamarelis, said the company had strict health and safety practices on site, but the high community transmission across the country meant the impact of COVID-19 was still a threat.
"All of our homes are being impacted by COVID," he said.
But high vaccinations and strong infection management have helped keep things relatively under control, he added.
Mr Mamarelis said the high case numbers were taking a devastating toll on the aged care workforce -- and he was worried about reinfection.
"We're seeing a lot of staff that are having to isolate who are contracting COVID," he said.
"We're not finding the backup -- they're just not there. So there's immense pressure [particularly] in those regional locations where team members are working 12-hour shifts."
Outside of aged care, large numbers of people continue to contract the virus in the wider community.
For some, it is not their first COVID infection.
Reinfections rising
Figures from across the country show there are now tens of thousands of Australians who have had COVID more than once, with "COVID reinfection" generally defined as a second encounter with the virus at least three months after the first infection.
In Victoria, more than 20,000 reinfections have been recorded. It is detecting reinfections through data-matching processes.
In New South Wales, that figure is more than 11,300 and nearly half of those occurred after the Omicron variant emerged there last November.
In South Australia, there have been more than 1,700 reinfections, and in the Northern Territory, there have been more than 220.
The ACT has recorded more than 670 reinfections -- and 70 per cent of those had both infections since the arrival of Omicron.
There have been 112 in Western Australia, which was the last state to re-open to Australia and the world.
Tasmania has only just begun tracking reinfections and does not have valid data yet.
Queensland does not collect information on reinfection.
Expat Fenella O'Brien is among those who have now experienced multiple infections.
"The first time it was pretty rough, pretty bad chest infection, I was out for the count," she said.
"Then the second time I got it, I thought it was going to be OK.
"But it ended up being a lot worse.
"I could not really get out of bed for so long afterwards. I really struggled to get my energy back and I just had such a long fatigue afterwards."
Why aren't politicians talking about COVID-19For some people, those symptoms can continue long-term. Not a lot is known about long-COVID but researchers are trying to change that.
According to the Australian Bureau of Statistics (ABS), there are now 47 Australians who have lost their lives to long-COVID.
For them, the infection led to serious and lasting complications — often lung diseases such as chronic pneumonia.
Virus has 'tricks up its sleeve'
Some countries, such as Denmark, have scrapped testing requirements, while others have been testing far less, meaning fewer COVID-19 infections are being recorded.
However, for many countries still recording data, reinfections are on the rise.
Alex Sigal, a virologist from the Africa Health Research Institute in Durban, was one of the researchers who first identified the Omicron variant.
"Omicron is very good at getting through pre-existing immunity," he told the ABC.
"In South Africa, we are at the tail end of a wave with Omicron sublineages BA.4 and BA.5, which were reinfecting a lot of people who were previously infected with the original [strain]."
Both sublineages are also present in Australia.
The good news, he said, was that the disease seems to be milder for most.
Professor Sigal recently researched samples from patients previously infected with the original Omicron strain.
While the sample size is small and the study is yet to be peer reviewed, it found the antibodies from the original Omicron BA.1 infection were not very good at dealing with the subvariants BA.4 and BA.5.
"These two sublineages evolved some mutations that enable them to escape from the original Omicron immunity," Professor Sigal said.
He said there was good immunity in the population because of vaccines and breakthrough infections, and he was encouraged by the fact most people infected made a full recovery and experienced milder disease. He said vaccines are working well to keep people from getting severely sick.
But he did have one major worry.
"It has tricks up its sleeve."
Omicron 'continues to surprise'
In Sydney, researcher Stuart Turville, a virologist from the Kirby Institute at the University of New South Wales and his team are learning more about immunity, particularly for those most at risk from the virus.
He said the antibodies appeared to be in decline much sooner in people who only experienced a mild illness.
"[You'd think] 'well, that's a good thing'," Dr Turville said.
"But [what's] left in terms of the antibodies? There is not a lot there and they are going to wane over time."
Like Professor Sigal, he believed nothing in this pandemic could be assumed or taken for granted.
"It has changed the way it gets into our body and enters cells [and] it continues to surprise us.
"This thing changes so fast, in the next six months we may not be talking about Omicron, we may be talking about the next letter in the Greek alphabet."
