Australia has been regarded as one of the world's success stories in dealing with the COVID-19 pandemic, but mixed messaging and a sluggish vaccine rollout has caused widespread frustration and confusion.

With only 11 percent of the population fully vaccinated despite a recent ramp-up, Australia sits at the bottom among the 38 members of the Organization for Economic Cooperation and Development, falling behind countries such as Japan, the United States and Britain.

Photo taken July 10, 2021, shows the Opera House in Sydney, closed under coronavirus lockdown restrictions. (Kyodo)

As countries around the world begin to open up and ease restrictions thanks to high rates of vaccination, Australians continue to face indefinite strict lockdowns, as authorities struggle with an outbreak of the highly infectious Delta variant that began in the country's largest city of Sydney.

With more than half of Australia's population of 25 million now plunged back into lockdown, frustration over the slow vaccine rollout is mounting, as state authorities say they have no choice but to continue imposing harsh restrictions until more people are vaccinated.

While countries like the United States and Britain secured deals with a range of vaccine manufacturers across the globe, Australia chose a different route, opting to place its bets on two vaccines that could be manufactured locally.

Only one of these, the AstraZeneca vaccine, turned out to be viable. But reports of a rare but serious blood clotting condition linked to the vaccine have caused serious setbacks to Australia's rollout, as the Australian Technical Advisory Group on Immunization, or ATAGI, responded by advising an age limit on people able to receive the AstraZeneca jab.

However, this limit has changed several times over a matter of months, going from people over 40, to the over-50s, to now the over-60s, causing widespread confusion and a blow to public confidence in the vaccine.

Many elderly citizens in the over-60s bracket no longer want to receive their second dose of the vaccine, and many of the over-50s scrambled to cancel their AstraZeneca appointments to seek out the Pfizer jab instead.

Beverly, a 71-year-old woman living in the suburbs of Sydney, said that while she wasn't hesitant to get her second dose, she was "furious with this federal government, because of its mixed messaging."

"I have friends who are holding off until they can get the Pfizer, and they're in my age group. They want to be inoculated, but they are terrified that they're going to be guinea pigs," she said.

Advice surrounding the AstraZeneca vaccine was complicated further in June when Prime Minister Scott Morrison encouraged Australians of any age group to speak to their doctor to receive the AstraZeneca shot, in defiance of the unchanged ATAGI advice recommending Pfizer as the preferred vaccine for the under-60s.

The prime minister's unexpected departure from expert advice sparked a backlash from several state leaders, including Jeannette Young, the chief health officer for the state of Queensland.

"I don't want an 18-year-old in Queensland dying from a clotting illness who, if they got COVID, probably wouldn't die," she said.

Lesley Russell, an adjunct associate professor at the Menzies Center for Health Policy at the University of Sydney, says that the rollout failures come down to three key issues: a lack of flexibility, poor planning, and a lack of transparency.

"Every mistake that could have been made was made," she said. "Our government was not flexible enough when things started to fall over."

Far behind the initial target of full vaccination by October, Russell fears Australia has lost all advantages it accrued from its early successes.

To date, Australia has had just over 32,000 cases of COVID-19, and a total of 915 deaths from the virus. Five of these are attributed to the latest outbreak of the Delta strain in Sydney, which currently sees 150 people hospitalized, and lockdowns in place across three states.