COVID-19 vaccine sales boosted Pfizer earnings well past expectations in the fourth quarter, but the drugmaker is setting a lower-than-expected bar for 2022.

Pfizer debuted on Tuesday annual forecasts for both earnings and revenue that fell short of analyst expectations even as the drugmaker expects another robust year of sales from its vaccine, Comirnaty, and its new coronavirus treatment, Paxlovid.

Its stock started sliding in early trading.

Pfizer expects Comirnaty to bring in another $32 billion in sales in 2022, while Wall Street is looking for more than $34 billion. Both the company and the Street expect another $22 billion in sales from Paxlovid, which received regulatory approval in the United States shortly before Christmas.

Overall, Pfizer forecasts adjusted earnings in the new year to range from $6.35 to $6.55 per share on $98 billion to $102 billion in revenue.

Industry analysts forecast earnings of $6.71 per share on $103.18 billion in revenue, according to FactSet.

Pfizer's two-shot coronavirus vaccine brought in $36.78 billion in revenue in 2021, its first full year on the market.

The $12.5 billion in sales it recorded in the fourth quarter helped Pfizer's top line double compared to the last quarter of 2020.

The COVID-19 vaccine became Pfizer's top selling product by last year's second quarter, before children started receiving the preventive shots and adults began receiving booster doses.

The New York drugmaker books the vast majority of revenue from Comirnaty and splits profit, as well as the cost to make and distribute the vaccine, with development partner BioNTech.

Outside Comirnaty and Paxlovid, Pfizer products include several cancer treatments, other vaccines and internal medicine drugs like Eliquis, for preventing blood clots and strokes.

Overall, Pfizer reported adjusted earnings of $1.08 for the fourth quarter on $23.84 billion in revenue.

Analysts expected earnings of 87 cents per share on $24.16 billion in sales for the fourth quarter.

Company shares fell more than 3%, or $1.97, to $51.24 before markets opened.