New York, Nov 11 (IANS): The US is planning start vaccinating the "most vulnerable" from next month if Pfizer's Covid-19 vaccine candidate is quickly approved by the drug regulators, US Health Secretary Alex Azar has said.

His comments came after Pfizer and BioNTech on Monday said that their vaccine candidate was found to be more than 90 per cent effective in preventing the disease in interim analysis of data.

As part of Operation Warp Speed, the federal government in the US signed an agreement with Pfizer in July for up to 600 million doses of the Covid-19 vaccine.

Pfizer is planning to ask the US Food and Drug Administration (FDA) for emergency use authorisation of its Covid-19 vaccine candidate very soon.

In an interview to CBS on Tuesday, Azar said that Pfizer will be producing 20 million doses of the vaccine every month over the next several months.

"In December we will be focusing on vaccinating the most vulnerable and then by the end of January we will have enough for all of our healthcare workers and first responders," Azar said.

The Health Secretary said that by the end of March or early April, the US should have enough vaccine for all Americans including other vaccines in the federal government's portfolio.