Pfizer Inc expects to generate $ 15 billion in revenue, or about a quarter of its total revenue this year, from the COVID-19 vaccine sales.

The company aims to deliver two billion doses of vaccine in 2021 at a breakneck speed as countries rush to sign supply agreements.

As of January 31st, Pfizer has shipped 65 million doses worldwide and 29 million doses in the United States. 

The company said it plans to deliver 200 million US doses by the end of May. Reuters estimates that it will have to deliver an average of about 10 million doses per week to achieve this goal - more than double the rate at which Pfizer and BioNTech doses were shipped to the United States in January.

However, in some European countries, deliveries were delayed due to changes in production processes in order to increase production.

The vaccine was one of the first approved for emergency use in the United States and some other countries.

Pfizer predicts sales of $ 59.4 billion to $ 61.4 billion by 2021, with vaccine sales expected to be nearly 25%.