For baby Austin, catching COVID would be dire.
His parents, Ben and Jacqui Messemaker, are hoping the newly available rapid antigen tests will help protect him.
The couple's five-month-old has multiple disabilities including cerebral palsy, that make any respiratory illness extremely dangerous for him, and specialists have advised his parents to take extra measures to protect him.
"We're trying to work out how do we best protect him whilst living somewhat normally," Ms Messemaker said.
"We've already spent the first seven weeks of his life in hospital and it doesn't take much to put us back there."
Rapid antigen COVID-19 tests, which recently became available in supermarkets across Australia, return results in about 20 or 30 minutes.
But they are less accurate than PCR tests which have been the main tests used in Australia throughout the pandemic.
Experts warn the tests will work best in such situations if used regularly.
Tests 'one small tool' to reduce risk
David Anderson, Burnet Institute's Chief Scientific Officer in the organisation's diagnostic initiative, said the "false sense of security" the tests provided concerned him.
"It's a useful tool but it's not a solution for forgetting about everything else," he said.
"It's just one small tool, and vaccination and ventilation are much more effective."
He said people with circumstances like having a vulnerable family member were more likely to be motivated to do rapid antigen tests properly, and compared it to settings that have already been using the tests.
"They're basically doing it the same way as a building site or an aged care home to protect their own family where the outcome is so much more potentially severe," he said.
"The only way that that works is to do it regularly."
Difficult balance to strike
Since COVID-19 restrictions eased and the Messemakers's other two primary age children, Leah, 9 and Spencer, 7, returned to school, the parents have a difficult balance to strike.
A few weeks ago, Austin caught a cold that Ms Messemaker and her daughter, Leah, had picked up, and he ended up needing hospital treatment.
"Our kids are obviously unvaccinated at the moment, and they're the biggest risk for us, coming into our household," Mr Messemaker said.
"We thought with rapid antigen testing that we would get them the earliest we could."
Mr Messemaker is an electrician, and he said the aged care home where he sometimes worked had already been screening visitors to the facility using rapid antigen tests, providing what he described as "an extra layer of protection".
Ms Messemaker said they were seeking advice from Austin's specialists about how they should use rapid antigen tests, but she said the cost would also factor in.
The major supermarkets have said the tests will sell for about $10 to $15 each.
'Extra level of safety' but no guarantee
The Krins family in Melbourne's east are grappling with a similar dilemma, and they have already started a testing routine for their extended family.
Tony Krins and his wife, Susan, are both 76,
Ms Krins suffers from type 2 diabetes and asthma — both conditions that make her particularly vulnerable to COVID-19.
They care for their primary school age grandchildren a few times a week, and until the children are able to get vaccinated, they want to use the tests to help reduce risk.
"We thought as a family we'd reduce risk pretty much as well as we could."
In the United States, the use of Pfizer to vaccinate children under 12 was recently approved, but Australia is yet to follow suit.
Dr Krins, who practised medicine during his career as an obstetrician and gynaecologist, said discovering that someone the family was in regular — and unavoidable contact with — was unvaccinated, had added extra concern.
He said he felt an extra level of safety with his family using the oral rapid antigen tests he had purchased.
"It's not as unpleasant as having something stuck up your nose, and the small children are quite happy to have it done," Dr Krins said.
"I think it's a useful tool, but I am mindful that it's not [a] guarantee."
Dr Anderson said if people were planning to use rapid antigen tests, using them regularly like the Krins family would be most effective.
"They really only give you good sensitivity for picking up infection if they're done regularly because you just don't stay positive on them for anywhere near as long as you do on PCR tests," he said.
Focus should remain on using tests 'well'
Deakin University epidemiologist Catherine Bennett said it was positive to see more widespread use of rapid antigen tests in environments like schools, aged care facilities and other workplaces.
"These rapid antigen tests are not perfect, they're not going to guarantee that you either have or have not got the virus depending on your test results," she said.
"But they are pretty good, and they're very good at screening out people who are at high risk of being infectious.
"That means they've got a very high viral load at that early stage of infection."
Professor Bennett said the use of regular testing in families with a vulnerable person could help detect the virus, but warned watching out for symptoms and knowing when family members had a high chance of being exposed was also very important.
"They can be helpful for monitoring what's going on — if there's risk from other people coming in and out of the household, monitoring visitors who may not be there every day," she said.
"[People should] be discouraging anyone with symptoms from coming near the house."
Professor Bennett said for people like the Messemaker and Krins families it was reasonable to use the tests, but regular, asymptomatic testing wasn't something people should be doing generally.
"Having a reason to do it makes sense, rather than just doing a whole lot of tests and then trying to figure out what it all means," she said.
"We want to actually use them well."
