As the global Covid-19 vaccination push gains pace there are hopes life will soon return to normal but one expert instead warns the world is entering a "new era".
Bloomberg's vaccine tracker estimates around 16 million vaccine doses are being delivered per day but even at this pace it would take two years for the world to vaccinate about 75 per cent of the population, and there are huge inequities between countries.
The United States, which is vaccinating about three million people a day on average, will take just three more months to vaccinate 75 per cent of its population.
The United Kingdom will be done in about five months, while Europe and India need another year.
This compares to places like Malaysia and Peru, which could more than four years to vaccinate their population.
And South Africa and Ukraine, where it will take more than 10 years.
The slow vaccination rollout in many countries will have implications for international travel and the risks that Australia is taking when opening its borders.
"In reality certain countries will be left behind and we'll see vaccine inequality at its worst," University of NSW Professor Mary-Louise McLaws told news.com.au.
Prof McLaws said it would "not be an acceptable risk ethically" for borders to re-open if every Australian who wanted to be vaccinated had not yet received both shots.
Even if Australia restricted overseas visitors to those who were vaccinated, she said there was still a chance someone could enter the country while carrying the coronavirus.
"There will be a proportion of those who have been vaccinated who could potentially be able to carry it into Australia, maybe because they have no symptoms or mild symptoms," she said.
If there is no quarantine or other testing, this would prove a risk for small outbreaks.
"So I don't think we can open our borders to anyone, even if they are vaccinated, without ensuring everyone at home who wants to be safe, is as safe as we can get them," Prof McLaws said.
She noted that almost half of Australia's population had family overseas or parents born overseas, and this would make it necessary for many to travel.
While the majority could go to safe places such as China, Taiwan, Hong Kong and South Korea, others could visit riskier regions.
"They may take a chance going to a place where there is a high amount of virus circulating because they need to see family or for family business," Prof McLaws said.
"You can't stop people going to certain places and they may go there indirectly."
As for Australians travelling overseas, Prof McLaws said it would also be an ethical dilemma to allow people who were lucky enough to be ahead in the vaccination queue to head overseas while others languished on waiting lists.
"We are a very equitable society, or at least we think we are, and so we've got to wait for everyone to have their second shot before we say people can go overseas," she said.
At Australia's current rate of vaccination, Prof McLaws believes it could take until March next year for 85 per cent of adults to get the jab, which is the proportion of the population likely needed for herd immunity.
However, Prime Minister Scott Morrison's announcement on Thursday night of new health advice for anyone under 50 to consider an alternative to the AstraZeneca vaccine, is likely to push this timetable back even further.
Prof McLaws said if Australia could get its vaccination rate to about 133,000 a day, then everyone who wanted to be vaccinated could get their jab by the end of the year.
However, at best about 70,000 jabs a day are being delivered currently.
While Australia doesn't need to achieve herd immunity within the country because it has effectively eradicated the virus, Prof McLaws said it was important for international travel.
"Herd immunity is important globally but we are not going to get that for at least two years," she said.
This means it is likely Australia will still need to have some form of at-home quarantine, rapid testing or other measures to deal with small outbreaks.
"This is not the beginning of the end," Prof McLaws said of the vaccine rollout, "this is the beginning of a new era.
"Eventually we will talk about when we had to put up with this 'light flu', but that won't be until vaccine inequity changes so that all these places where our relatives and friends come from, and where we want to go, have a high level of vaccine uptake," she said.
"It's for their protection but also for the world."
Once Australia opens up for international travel, Prof McLaws said it needed to make sure it was as safe as possible but it wouldn't be 100 per cent perfect.
"We will still get little outbreaks, although they won't be as big because of the vaccinations," she said.
The Path to global immunity
How long it will take selected countries to immunise 75% of their population, based on vaccination rates.
Months to cover 75% of the population
United Kingdom: 6
South Africa: 120
Vaccination rate (doses per day)
United Kingdom: 339,576
South Africa: 1,223