Shares in GSK erased losses and traded more than 7% higher on the report, and were last up 5% at 1151 GMT.

A GSK spokesman declined to comment on the report. Elliott did not immediately respond to a request for comment.

Britain's GSK warned in February of a bigger than expected fall in 2021 earnings as the COVID-19 pandemic continues to disrupt other healthcare treatments and it invests in new medicines ahead of a split from its consumer products business next year.

Rather than developing its own COVID-19 shot, GSK has so far focused on supplying its vaccine booster to other drugmakers. But a project with Sanofi has been delayed, and China's Clover has ended its deal with the British drugmaker.

GSK, the world's biggest vaccines maker by sales, in February announced a deal with Germany's CureVac to work on a next generation of shots to combat new COVID-19 variants.

GSK's shares had been down nearly 4% in 2021 before the rally on Thursday.

(Reporting by Alistair SmoutAdditional reporting by Svea Herbst-Bayliss in BostonEditing by Keith Weir)