By Manojna Maddipatla and Manas Mishra

(Reuters) – Moderna Inc said on Thursday it expects COVID-19 vaccine sales of $18.4 billion this year, above the $15 billion in sales forecast by Pfizer Inc for the only other vaccine authorized for emergency use in the United States so far.

Both vaccines, developed using a technology based on messenger RNA (mRNA), are being distributed at an unprecedented speed as cases mount in the United States, with deaths from COVID-19 surpassing the dire milestone of 500,000.

Moderna, whose shares rose 4% to $150.7 in trading before the bell, has been aiming to ramp up production of the vaccine, its first and only revenue-generating product.

It now aims to produce at least 700 million doses this year and expects to raise production to as much as 1 billion doses by improving its manufacturing process..

“2020 demonstrated the power of harnessing mRNA to make medicines,” Chief Executive Officer Stéphane Bancel said in a statement.

“I believe that 2021 will be an inflection year for Moderna.”

Moderna expects cost of sales to be about 20% of product sales in 2021, well above the 4% it recorded a year earlier.

The company also said it had completed enrollment for a mid-to-late stage study of the vaccine in adolescents between the ages of 12 and 17, while a study in children aged six months to 11 years will start in the near-term.

Moderna’s chief medical officer, Tal Zaks, would leave the company in late September, the company added.

(Reporting by Manojna Maddipatla and Manas Mishra in Bengaluru; Editing by Anil D’Silva)