When Premier Mark McGowan announced WA's planned reopening had been canned, he made it clear the decision was heavily influenced by the state's low booster rate.
"It would be reckless and irresponsible to open up now, I can't do it," the Premier said.
He said many people had yet to have the opportunity to get their third dose (or booster shot) of the COVID vaccine, which would make opening on February 5 dangerous.
But the delay has raised questions about whether increasing the overall booster rate is worth the waning immunity it could bring for some.
We spoke to the experts to find out what should happen next.
Does the protection afforded by vaccines wane over time?
First of all, it's important to remember that vaccines are only one of the tools we have at our disposal to try to control case numbers.
Wearing masks, getting tested and putting cases into isolation are all also important factors.
You should also keep in mind that each person's response to both COVID and vaccines will vary depending on a range of factors.
On vaccines specifically, we're still relatively early in the rollout, so the impact of them is still a bit tricky to measure.
We know from the data used by Australia's vaccine advisory body that around six months after a person's second dose with an mRNA vaccine (like Pfizer or Moderna), protection waned to about 40 per cent against symptomatic disease and 80 per cent against severe disease.
Following a booster with an mRNA vaccine, protection against Omicron jumped to 86.2 per cent for symptomatic infection, and 98.2 per cent for severe infection.
The UK also has some useful data to answer this question, because it started its booster rollout in September, two months earlier than Australia.
According to information from the country's Health Security Agency last week, the effectiveness of a booster against symptomatic COVID-19 between two and four weeks after receiving it is about 60 to 75 per cent.
After 10 weeks, or about two-and-a-half months, that drops to about 45 to 50 per cent.
After 15 weeks, or just shy of four months, it sits at about 25 to 40 per cent.
When it comes to protecting against hospitalisation, the UK data shows that a Moderna booster was associated with protection of between 90 and 95 per cent up to nine weeks after vaccination.
On the other hand, the effectiveness of a Pfizer booster starts at about 90 per cent, before dropping to 75 per cent after 10 to 14 weeks.
What kind of protection will we have when borders open?
That will depend on exactly when we open, but modelling from the University of Western Australia's George Milne and Julian Carrivick shows it will likely reach its peak in the coming weeks.
He said there will likely be a period of a few weeks where overall immunity plateaus, before it starts to drop.
The only way to increase it from there, according to Professor Milne, will be the immunity people develop after being infected with COVID-19.
WA's Chief Health Officer Andy Robertson has told the government that beyond March, waning immunity will start to bite.
Health Minister Amber-Jade Sanderson said that was something the government was thinking about, but so too was the furloughing of staff across industries that has been seen in other parts of Australia.
"The logic falls on deferring that date, it falls on slowing that down," she said.
Ms Sanderson continued to stress the importance of vaccination in trying to limit the spread of COVID-19 in WA.
"The vaccine is still your greatest protection against this disease," she said.
The Health Minister also urged people to get the vaccine to protect those around them who might be vulnerable.
What about those who got their boosters early?
For people who got their boosters early in the rollout, it's expected the benefits could start to dip around April.
It's not an issue at the moment, but depending on how far along the reopening gets pushed, it certainly could be.
"One of the factors that also has to be taken into account is the potential waning immunity of healthcare workers and vulnerable people who were among the first to get their boosters," the head of the Australian Medical Association in WA, Mark Duncan-Smith, said.
"But another factor to keep in mind is that an mRNA booster takes about 100 days to develop, and these are variant-specific boosters.
"So it may be that, for example, an Omicron booster may be specifically available, that may coincide with approximately April."
Both Pfizer and Moderna last week announced they would begin clinical studies into Omicron-specific boosters.
But researcher Deborah Burnett warned this approach would not work forever.
"Waves of new variants would engulf the population faster than variant-specific vaccines could ever be deployed," she told The Conversation.
So when should I get my booster?
The consensus is that you should be getting your booster as soon as you become eligible.
"We already have community transmission in WA, so people should not be basing their boosters on the border opening," UWA infectious diseases expert Barbara Nattabi said.
"They should be basing their boosters on the fact that we already have community transmission, and we do not know when people have been exposed."
That was particularly important because of the case numbers the state is currently seeing, she said.
Dr Nattabi said it was also important to remember that there will probably be a rush on vaccination bookings when the new date was announced.
"The very fact that it takes a while to get an appointment means that if you wait until they announce the borders are opening, by the time you actually get your vaccination the border might already be open.
Dr Duncan-Smith, was on the same page.
"If you've got your booster appointment due, I recommend you get it done," he said.
"The reason for that is we've already got Omicron out there, spreading in society.
