Of the two billion COVID-19 vaccine doses distributed globally till now, about 60 per cent have gone to just three countries - the US, India and China, a senior adviser at the World Health Organisation said.

Senior Advisor to WHO Director-General Tedros Adhanom Ghebreyesus, Bruce Aylward made the comments at a press briefing on Friday.

This week, we will see over two billion doses we will probably pass the two billion doses landmark in terms of the number of doses of the vaccines and new COVID-19 vaccines that have actually been developed. These have been distributed now in over 212 countries, Aylward said.

If we look at that two billion doses, over 75 per cent of it has gone to just 10 countries. And in fact three countries - China, the US and India - account for about 60 per cent of those doses, he said.

He said while COVAX has played an important role in distributing the COVID-19 doses to 127 countries and getting several countries to start their vaccination drives, the challenge is in the access to the vaccines.

He said the 60 per cent of the two billion doses that have gone to China, India and the US are all domestically procured and used .

Aylward noted that at the other end of the spectrum , only about 0.5 per cent of doses globally have gone to the lowest income countries that account for about 10 per cent of the world's population.

And even if we look at the lower middle income countries, it's only fractionally higher than that in terms of the coverage that we're getting. So we're increasingly seeing a two-track recovery and rollout of the vaccines, he said.

While there is high vaccine coverage deep into the high risk populations and younger populations in high income countries, we are still struggling to get sufficient product just to be able to vaccinate the health care workers, older populations in low income countries who are really the key to getting out of the health, societal and economic crisis that we are in the midst of.

Aylward said about 80 million doses have been distributed through COVAX so far and the global alliance for equitable vaccine distribution is about 200 million doses behind where it should be due to the disruption in COVAX supplies as a result of the devastating second wave in India.

The problem now is the supplies are being interrupted. We're having disruptions because of the problems in India and others and having trouble filling that gap. And as a result, the countries are having trouble getting momentum and getting started well.

"We saw how long it took to get the scale up of vaccines in high income countries. It takes a consistent supply of vaccines. So this is the crucial piece that we've got to fix in the next two months if we are going to be on track to get out of the pandemic," Aylward said.

He added that through COVAX, we've distributed just about 80 million doses at this point. We're about 200 million doses behind where we want to be because of the interruption of supply out of India because of the need to redirect them there. And also because of the challenge that we're having getting other manufacturers to scale up and come online early enough, such as the Johnson and Johnson product.

He said while there are commitments in principle of about 150 million doses to be donated through COVAX, there are two big problems with that.

Number one, very little of it is committed for the June-July period, which means we're going to still have this gap. The other problem is just the volume. If we are going to get on track to get at least 30-40 per cent of the world vaccinated this year, we got to get another 250 million people vaccinated between now and the end of September.

We expect India SII (Serum Institute of India) volumes to open up again in the fourth quarter at least, he said, adding that countries are going to fail unless they get vaccines early to start rolling out, building community confidence, building their systems. But we're setting up for failure if we don't get early doses.

The Serum Institute of India (SII), the world's largest vaccine manufacturer, is the key supplier of AstraZeneca doses to COVAX. However, supply of vaccines from SII to COVAX has been impacted as the second wave of the COVID-19 pandemic ravages India.

Last month, Ghebreyesus had said that once the devastating outbreak in India recedes, we also need the Serum Institute of India to get back on track and catch up on its delivery commitments to COVAX.

In response to a question on the situation in India and Nepal, which are seeing devastating surges in COVID-19 cases, he said, are we concerned about India and Nepal. Absolutely. We've got escalating epidemics in different parts of India still. (It's) going down overall but some areas are still hard hit.

In Nepal too, areas are hard hit. Still real gaps in terms of what they need to be able to save lives in real time, as well as protect people with vaccines so as we look for doses and bringing the doses forward, the goal is to be able to get more doses surged into these places that are being hit, so that we can reduce the risk of death in the face of these escalating outbreaks as well.