Johnson & Johnson has suspended its sales forecast for Covid-19 vaccines due to a global supply surplus and demand uncertainty - and cut its adjusted profit expectation, sending the drugmaker's shares down nearly 3%.

The company had earlier predicted as much as $3.5 billion in sales from the shot, which has fared poorly compared to rivals due to low demand in the United States and safety concerns.

J&J now expects its full-year adjusted profit forecast to be between $10.15 and $10.35 per share, lower than the prior forecast of $10.40 to $10.60.

Sales of the vaccine last year had underperformed rival mRNA shots due to manufacturing bottlenecks, safety concerns and an uneven vaccine demand.

Pfizer has forecast $32 billion in 2022 sales from its Covid vaccine it developed with BioNTech, while Moderna has forecast $21 billion.

The New York Times had reported in February that J&J shut down the only plant making usable batches of its Covid-19 vaccine late last year.

Production at contract manufacturer Emergent BioSolutions' plant in Maryland was halted by the US Food and Drug Administration last year after an accidental mix-up of ingredients ruined about 15 million doses of the vaccine.

Shares of Johnson & Johnson were trading down at $172.74 before the opening bell.