Moderna Inc on Thursday projected higher vaccine sales for the second half of the year as it sees COVID-19 becoming a flu-like endemic illness, prompting people to take regular shots.

The company expects $19 billion in sales of its vaccine this year from $18.5 billion previously, and said talks were ongoing for vaccine orders in 2023.

Moderna has said its vaccine will be priced below value during the pandemic period, and that it will change its pricing strategy as COVID-19 shows signs of subsiding.

The company also said it was working on a new "bivalent" booster vaccine, which combines an Omicron-specific booster and its original COVID-19 vaccine.

With just a single product on the market, Moderna has been banking on the sales of its shot to help sustain its research and development efforts as it looks to build a large portfolio of vaccines and treatments using mRNA technology.

Shares of Moderna, which announced a plan to buy back $3 billion in stock, fell nearly 4% in trading before the bell amid a slump in the broader markets.

Moderna had previously projected sales of $18.5 billion from its vaccine, with an additional $3.5 billion in options. It now expects $3 billion in options.