The Therapeutic Goods Administration has signed off on the release of 800,000 locally manufactured AstraZeneca vaccines, which might soon help boost the total number of shots delivered in Australia.

So far, Australia's rollout of the vaccine has been slow - due in part to limited supply but also due to the way the system has been set up to deliver vaccines.

But the reality is that to vaccinate the entire population by the target date of October, there'll have to be a serious ramping up soon.

So as today's Coronacast explains, with every passing day, the harder it'll be to reach those targets.

Also on today's show:

* We have a TGA response to (some) questions regarding German research into reports of blood clotting issues surrounding AstraZeneca vaccines

* What we know and what we don't about blood clotting reports

Researchers in Germany say they've identified what could be behind the reports of blood clotting in people who have had the AstraZeneca coronavirus vaccine.

The German team - in yet to be released pre-print research - say that the vaccine could in rare circumstances cause an autoimmune reaction that leads to clots.

The findings have yet to be peer reviewed, but the team says people who are likely to be affected could be identified if they are at higher risk by a screening test.

So on today's Coronacast, a rundown of the findings that could offer a reason for the reported blood clotting issues.

The UK and Europe are vaccinating people in their millions but the scale of the pandemic there means they're still in catch up mode.

Experts have warned that variants that may not be fully covered by our current vaccines are continuing to emerge and spread.

So on today's Coronacast, while here in Australia we're still sitting relatively pretty with very few cases, what does this mean for our ability to reopen borders anytime in the foreseeable future?

For those with symptoms of COVID months after being infected, there could be good news on the horizon.

People with long COVID report being fatigued and unable to concentrate after contracting the virus.

Now a study - which has not yet been peer-reviewed - has found that some long COVID sufferers report feeling significantly better in the days after receiving a coronavirus vaccine.

On today's Coronacast, what could this study mean for people suffering from long COVID and what does it tell us about COVID-19?

Also on today's show:

* What could Europe's Astra pause mean for the global rollout?

* What do reports of blood clotting mean for people who've had strokes or clots in the past?

* A baby of vaccinated mother born with antibodies

The government has been urging Australians to embrace covid vaccines but now that phase 1b is just days away, the infrastructure underpinning this is being put to the test.

About 6 million Aussies fall into the coming phase, and about 1000 GP clinics are part of the rollout plan.

But many people, keen to get the vaccine and trying to book appointments, are being told clinics listed on the government website aren't part of the rollout, or that they haven't yet received vaccines and don't know when they will.

On today's Coronacast, why is it so hard for Australia to scale up its vaccination rollout? And do these early delays risk putting people off getting their shots?

Also on today's show:

* A look at why Germany may have halted the AstraZeneca rollout

The government has been urging Australians to embrace covid vaccines but now that phase 1b is just days away, the infrastructure underpinning this is being put to the test.

About 6 million Aussies fall into the coming phase, and about 1000 GP clinics are part of the rollout plan.

But many people, keen to get the vaccine and trying to book appointments, are being told clinics listed on the government website aren't part of the rollout, or that they haven't yet received vaccines and don't know when they will.

On today's Coronacast, why is it so hard for Australia to scale up its vaccination rollout? And do these early delays risk putting people off getting their shots?

Also on today's show:

* A look at why Germany may have halted the AstraZeneca rollout

Australian health authorities and regulators have assured the public that there is currently no evidence to suggest the AstraZeneca coronavirus vaccine is not safe or is causing blood clots.

It's come in response to several European countries pausing the AstraZeneca vaccine rollout amid blood clot concerns.

The European Medicines Agency is currently investigating reports, and is due to report back on Thursday, and as such the Australian rollout will continue.

So on today's Coronacast, what we know and what we don't about this whole story about blood clots.

It's now several weeks into Australia's vaccine rollout, and while people are being immunised daily, there hasn't exactly been a massive ramp up.

165,000 people have been immunised so far, which is behind what the Federal Government had hoped to achieve.

The target was 4 million people initially set for early April, which is only a few weeks away.

So on today's Coronacast, what's the hold up with the vaccine rollout? Supply or delivery?

Also on today's show:

* Astra effective against 1.351 and B117 (in Syrian hamsters)

* Queensland worried about coronavirus wave in PNG

* A bit more on the NSW security guard who tested positive for COVID-19, despite being vaccinated

Coronavirus has slipped past our infection control systems once again, with health authorities in two states again chasing down the virus.

In NSW, the hotel quarantine system seems to have been breached with a vaccinated security guard testing positive over the weekend.

And in Queensland, a doctor has been infected after assessing a known COVID positive patient in hospital.

So on today's Coronacast, can we expect this to happen less once the vaccine is further rolled out to frontline workers or is something we have to keep living with?

Also on today's show:

* Please tell us about the stories saying that the Astra-Zeneca vaccine is causing blood clots

* A survey shows more people want to get vaccinated than in December 2020

Coronavirus has slipped past our infection control systems once again, with health authorities in two states again chasing down the virus.

In NSW, the hotel quarantine system seems to have been breached with a vaccinated security guard testing positive over the weekend.

And in Queensland, a doctor has been infected after assessing a known COVID positive patient in hospital.

So on today's Coronacast, can we expect this to happen less once the vaccine is further rolled out to frontline workers or is something we have to keep living with?

Also on today's show:

* Please tell us about the stories saying that the Astra-Zeneca vaccine is causing blood clots

* A survey shows more people want to get vaccinated than in December 2020