Moderna (MRNA  ) sold $5.9 billion of its COVID vaccines in the first quarter, topping both revenue and profit expectations as the company worked to meet high vaccine demand. The biotech is also forecasting strong sales outlook globally for 2022.

Moderna's total revenue of $6.1 billion, which more than tripled from its first year last year, was almost fully driven by COVID vaccine sales (representing 98% of total revenue), as its vaccine is the company's only commercially available product.

The company maintained its full-year guidance of $21 billion for COVID vaccine sales. That guidance is based on signed agreements with governments not including any orders from the United States, meaning the final total could be higher by the year's end.

However, Chief Financial Officer David Meline said there is some uncertainty surrounding this year's sales guidance in the company's earnings call on Wednesday, citing the World Health Organization's (WHO) COVAX decision against having the option to purchase additional doses this year.

Still, company executives are expecting strong vaccine sales heading into the second half of the year. Chief Executive Officer said Moderna expects more governments to order doses ahead of their fall vaccine campaigns and programs,CNBC reports. Bancel also said the biotech expects to receive regulatory approval before the fall season for its COVID vaccine that targets the mutations on the Omicron variant in addition to the original SARS-CoV-2 strain.

The company plans to release data on that "bivalent" vaccine in June, President Stephen Hoge said during Moderna's earnings call. "Because we think this will be a seasonal vaccine, [vaccination] will be very similar to what people are used to from a flu perspective," Hoge said.

Moderna's current generation COVID vaccine received full approval for use in adults ages 18 years and older from the U.S. Food and Drug Administration (FDA) back in January, making it the second COVID vaccine to be fully approved for adults in the United States after Pfizer (PFE  )-BioNTech's (BNTX  ) approval in August 2021.

The company recently submitted data to the FDA in request of an emergency use authorization for its current vaccine for children ages six months to under six years in age, the only age group not eligible for vaccine in the U.S. Moderna has previously requested EUAs for children ages 6 to 11 and ages 12 to 17, and approvals for these age groups could also drive more vaccine sales.