Adar Poonawalla, CEO of vaccine major Serum Institute of India (SII), on Sunday urged other countries to be patient as they wait for the supplies of COVID-19 vaccine, Covishield, as the company has been directed to prioritise the needs of India.

Apart from making efforts to meet the requirements of India, the company is also trying its best to balance the needs of the rest of the world, he added.

"Dear countries and governments, as you await #COVISHIELD supplies, I humbly request you to please be patient, @SerumInstIndia has been directed to prioritise the huge needs of India and along with that balance the needs of the rest of the world. We are trying our best", Poonawalla said in a tweet.

On February 15, the World Health Organisation (WHO) listed two versions of the AstraZeneca/Oxford COVID-19 vaccine for emergency use, giving the green light for these vaccines to be rolled out globally through COVAX.

The vaccines are produced by AstraZeneca-SKBio (Republic of Korea) and the Serum Institute of India.