India will likely take at least three to four months to complete Covid-19 vaccination efforts for frontline workers and people over 60 or with underlying health conditions, the executive director of the Serum Institute of India said Thursday.

In January, the South Asian country launched the world’s largest vaccination campaign for around 300 million people out of its massive population of 1.3 billion. According to the Indian Ministry of Health, more than 36 million people had been vaccinated by Wednesday evening.

“The number of doses required in India is enormous,” Suresh Jadhav told CNBC’s Capital Connection, adding that the vaccination program is a gigantic task that cannot be completed in a short period of time.

“This program will continue at a rate of about 50 (million) to 60 million doses per month and cover that population of 300 million in an additional three to four months,” he said.

Jadhav attended the Asian Development Bank’s Southeast Asia Development Symposium 2021 this week.

Based in Pune, India, the Serum Institute has become a key player in the Covid vaccination effort in both India and around the world. It is the largest vaccine maker in the world by volume, making the Covid-19 vaccine developed by Anglo-Swedish pharmaceutical giant AstraZeneca and Oxford University, known locally as Covishield.

It has delivered millions of doses to the Government of India as well as Covax, a global vaccination initiative led by the World Health Organization and others, to ensure an equitable distribution of the shots in less affluent countries.

An exterior view of the Serum Institute of India Pvt. Ltd., which is manufacturing a Covid-19 vaccine on November 23, 2020 in Hadapsar, Pune, India.

Pratham Gokhale | Hindustan Times | Getty Images

In response to growing demand for its Covid vaccine, Adar Poonawalla, CEO of the Serum Institute, asked foreign governments to be patient last month and said, without further explanation, the company had been asked to meet domestic demand first.

Jadhav stated that the Serum Institute is able to fulfill current orders from the Indian government and said it has already delivered around 59 million doses to Covax. He added that the Serum Institute plans to expand capacity by late April or early May to add another 40 to 50 million doses to production.

Currently, the Serum Institute can reportedly produce more than 70 million doses per month.

Last week, the U.S., Japan, and Australia pledged to help Indian companies expand their Covid vaccine manufacturing capacity and add more doses to the global supply pool.

India also uses a locally developed vaccine from Bharat Biotech, which was developed in collaboration with the Indian State Council for Medical Research.