Some six months since the World Health Organisation declared Covid-19 a global health emergency, the “once-in-a-century” pandemic has become a great leveller with an overarching one-size-fits-all spread across the world.
But the virus has divided the world in countless ways too. 
The fast emerging vaccine nationalism has shed the spotlight on the rich-poor-divide when it comes to finding an effective cure for the pandemic that has killed more than 680,000 people and infected more than 17.5mn.
While the race to develop an effective vaccine, or drug, against Covid-19, involving more than 30 countries, entails cross-border collaboration, it also has brought about high-stakes competition. 
Some countries are now using their research dollars to try to buy the first place in line for supplies in the event an experimental vaccine proves effective. 
Public health specialists warn that such inward-looking vaccine nationalism could result in the pandemic lasting longer, by preventing the most efficient allocation of shots to prevent Covid-19.
Although international groups and a number of nations are promising to make vaccines affordable and accessible to all, doses will likely struggle to keep up with demand in a world of roughly 7.8bn people. 
The US, Britain, European Union and Japan have so far secured about 1.3bn doses of potential Covid immunisations, according to London-based analytics firm Airfinity. Options to snap up more supplies or pending deals would add about 1.5bn doses to that total, its figures show.
The WHO, the Coalition for Epidemic Preparedness Innovations, and Gavi, the Vaccine Alliance are working together to bring about equitable and broad access. They outlined an $18bn plan in June to roll out shots and secure 2bn doses by the end of 2021.
The initiative, known as Covax, aims to give governments an opportunity to hedge the risk of backing unsuccessful candidates and give other nations with limited finances access to shots that would be otherwise unaffordable. 
If governments put their own interests first, it could result in a worse outcome for everyone, allowing the virus to continue to spread, some officials warn.
Some 78 nations have expressed interest in joining Covax. In addition, more than 90 low- and middle-income countries and economies will be able to access Covid vaccines through a Gavi-led programme, the group has said. 
There’s still concern the rest of the world might fall behind.
For sure, rich countries taking a monopolistic approach on the vaccine are likely to reduce vaccine access for other poorer countries and drive up prices. 
The wider concern is that the world will see a repeat of the situation in the last pandemic, when rich nations purchased all the available supply of vaccines against the H1N1 flu virus in 2009-10. 
Global health experts say that the pandemic will be controlled fastest if a future vaccine is deployed in the most efficient way possible. It would ensure the first doses going to groups around the world that are at the highest risk – such as healthcare workers, the elderly and the like – rather than to whole populations in the richest countries.