It has been one of history's great scientific achievements. It took just 333 days from the moment Chinese officials released the genetic map, or genome, of COVID-19 in January to the first person being injected with an approved vaccine. The first recipient, 90-year-old grandmother Margaret Keenan from central Britain, said she felt "so privileged".

With most vaccines taking 10-15 years to create, the less than one-year time frame for a COVID-19 vaccine has smashed all records. At a time when the virus is still ravaging many parts of the world, particularly in the northern hemisphere, the lightning speed progress of a vaccine is a blessing. If only that was the most challenging aspect.

The daunting task of manufacturing, distributing and administering enough doses of approved vaccines is now becoming a reality. Of most concern has been the battles being waged by particularly wealthy nations to purchase many millions of doses even before the vaccines have been given the green light.

With those with the greatest buying power pre-purchasing vast amounts of potential vaccines – more than 3.8 billion doses have already been bought by high-income countries, which is more than all other nations combined – there is growing concern about how long some nations will have to wait in line.