LONDON: Two billion doses of the AstraZeneca-Oxford University COVID-19 vaccine have been supplied worldwide, the Anglo-Swedish drugmaker and its partner said on Tuesday, in just under a year since its first approval.

The shot, which is the biggest contributor to the COVAX vaccine sharing scheme backed by the World Health Organization, is being made in 15 countries for supply to more than 170 countries, London-listed AstraZeneca and Oxford University said in a joint statement.

AstraZeneca in June last year signed on India's Serum Institute, the world's biggest manufacturer of vaccines by volume, to help double the vaccine's manufacturing capacity to two billion doses.

The ChAdOx1 nCoV-19 shot, sold under the brand names Vaxzevria and Covishield, has faced challenges around efficacy data, supplies and links to rare blood clots.

AstraZeneca last week said as the world learns to live with the coronavirus which causes COVID-19, it would begin to earn a modest profit from the shot after having made a commitment to sell it at cost during the pandemic.

The company's chief executive officer, Pascal Soriot, however, reassured that low-income countries would continue to receive vaccines on a non-profit basis.