It is hoped the first Europeans could get a COVID-19 vaccine as early as the end of the year after several pharmaceutical firms announced successful trials.
But with a vaccine having seemingly been found in record time, attention now turns to the challenge of distributing it to the world's population of 7.5 billion.
We spoke to two experts to find out the major hurdles health authorities must overcome to get the vaccine delivered to all corners of the globe.
The three candidate vaccines require two shots — although the AstraZeneca/Oxford University has proved more effective when the first shot is a half dose.
AstraZeneca has announced plans to produce 3 billion doses over the next year while BioNTech/Pfizer is planning to manufacture 1.3 billion.
These targets "seem to be feasible," said Dr Zoltan Kis, from the department of chemical engineering at Imperial College London. "However, the global demand when assuming 2 doses per person is far from being met by the end of 2021."
Prashant Yadav, professor of strategy at the INSEAD Business school, told Euronews that "it could take up to 2.5 years to manufacture the more than 10 billion doses needed for global coverage".
"Routine vaccines are stored and distributed between 2-8°C. There is sufficient infrastructure for cold storage and distribution at that temperature range in high-income countries, and through the efforts of GAVI (the Vaccine Alliance), the Gates Foundation and UNICEF, sufficient capacity has also been built in Africa, South Asia and other less developed regions of the world to store and distribute vaccines between 2-8°C," Yadav said.
The problem is that out of the three vaccine candidates so far, only one falls in that temperature range — AstraZeneca's.
Pfizer/BioNTech and Moderna's vaccines have cooling requirements of -70°C and -20°C respectively.
"Pfizer-BioNTech vaccines require ultracold chain [infrastructure] which doesn't even exist in EU and USA with the exception of a few academic medical centres and a few specialised distribution centres," he added.
Pfizer has developed a special freezer box which can keep the vaccine safe to handle for up to 10 days but still, its distribution to "low and middle-income countries or rural areas of other countries is challenging due to the lack of appropriate freezing temperatures," Dr Kis said.
As for the Moderna vaccine, according to Yadav, although "it can withstand 2-8°C for a few weeks," manufacturing capacity is "not that much".
"So their supplies would not be available outside of the US, Canada, EU," he added.
Overall, Dr Kis, concluded, "Europe and North America are considered to have the most capacity for distributing and storing vaccines at low temperatures, such as -70°C, relative to their population."
"On the other hand, sub-Saharan Africa is considered to be in the worst position when it comes to low and ultra-low temperature vaccine distribution," while "the other continents fall somewhere in between," he added.
Urban vs rural
Because of the cooling requirements which will impact transport as well, access to the vaccine in rural and remote areas will be more difficult than in large cities.
Furthermore, the packaging of the Pfizer vaccine is in 1,000 dose containers, according to Yadav.
"Some rural clinics don't have the ability to absorb those many doses in a short 2-3 day time interval. Staff who can act as a vaccine administrators are lacking in rural areas.
"Vaccine administration also requires PPE [personal protective equipment] for the staff who will administer the vaccine and the supply chain to deliver PPE to rural areas is challenging," he also pointed out.
'Highly challenging' immunisation campaigns
"The administration of vaccines to patients is another highly challenging process," Dr Kis said.
This is due to the time required to immunise people — including a 10-15 minute recovery period after the vaccine is administered — and to log each procedure properly.
Social distancing requirement and the "limited number of medics/vaccinators available per capita" —which is even less in low and middle-income countries — compound the issue.
"Furthermore, vaccine administration requires the highest amount of human involvement, so additional challenges/issues can occur at this stage, especially when considering that two doses of vaccines need to be administered per person usually 3-4 weeks apart," he added.
_This article was amended as an earlier version erroneously quoted Prashant Yadav as Phanish Puranam. _