"People do not tend to realise that India is amongst the two most populous countries in the world and the vaccination drive for such a population cannot be completed in two to three months," Poonawalla said in a statement on Tuesday.
"It would take 2-3 years for entire world population to get fully vaccinated."
As second wave of coronavirus took control in India, many states reported severe vaccine shortages at the same time and even halted inoculation drives for people in 18-44 age group.
The Central government, particularly, has come under heavy crticism for its botched up vaccination strategy and not ordering enough vaccines to give to the people.
"We must also understand that this pandemic is not limited by geographic or political boundaries. We will not be safe until everyone in the world is able to defeat the virus," Serum CEO further said.
"Serum has delivered 200 million doses, even though we received emergency use authorisation (EUA) two months after the US pharma companies. If we look at the total doses produced and delivered we rank among the top three in the world," he added.
Serum said it continues to produce vaccines at scale and prioritise India, and it hoped that it will start delivering vaccines to Covax and other countries by the end of this year.
India is unlikely to resume major exports of vaccines until at least October as it diverts shots for domestic use, a Reuters report said.
India halted vaccine exports a month ago after donating million of doses to many countries. The move has left countries including Bangladesh, Nepal, Sri Lanka and many in Africa scrambling for alternate supplies.
India’s cumulative vaccination coverage surpassed the 180 million mark. More than 6.6 million beneficiaries aged between 18 to 44 years have been vaccinated so far, according to the Ministry of Health and Family Welfare
 "Covishield")