Pfizer Inc. PFE shares are trading lower on Wednesday after a Wall Street Journal report revealed U.S. prosecutors are investigating a claim about the timing of Pfizer's COVID-19 vaccine announcement.

What To Know: The claim, brought forward by British pharmaceutical company GSK, alleges Pfizer may have delayed announcing the success of its vaccine trials in 2020 until after the U.S. presidential election.

According to sources, the investigation stems from a GSK scientist, who used to work at Pfizer, allegedly telling his GSK colleagues that Pfizer delayed the vaccine results, a claim President Donald Trump repeated for years without evidence. The scientist disputes that he did this, stating Pfizer worked as quickly as possible to secure FDA approval.

Prosecutors have already interviewed at least two individuals in connection with the claim, including a GSK executive who documented the conversation. A third person is expected to be interviewed soon, though Pfizer executives have not yet been questioned. Pfizer maintains that its vaccine development was driven purely by science and regulatory oversight, dismissing any allegations of impropriety. The company has not received formal inquiries from prosecutors.

Trump, who has long criticized the timing of Pfizer's announcement, has personally questioned Pfizer CEO Albert Bourla about the matter. Bourla has denied any deliberate delay. Internal reports indicate that Pfizer aimed for an October 2020 completion but faced the complexities of clinical trials and regulatory approval.

The investigation adds another layer to the ongoing rivalry between Pfizer and GSK, which have battled over COVID-19 treatments and RSV vaccine patents in recent years.

PFE Price Action: Pfizer shares closed Wednesday down 1.33% at $25.21, according to Benzinga Pro.

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