Moderna said on Wednesday it had withdrawn an application seeking approval for its flu and Covid combination vaccine candidate after discussions with the US Food and Drug Administration.

The company said it would resubmit the application later this year with vaccine efficacy data from a late-stage trial of its experimental seasonal influenza vaccine, which it expects to report this summer.

The decision comes a day after the US FDA said it would require new clinical trials for approval of annual Covid-19 boosters for healthy people under 65 years old.

Shares of the company have been battered by declining Covid revenue as well as investor concerns spurred by the appointment of the vaccine skeptic Robert F Kennedy Jr as secretary of the Department of Health and Human Services.

The shares fell another 1.4% in premarket trading on Wednesday.

The FDA is due to make a decision on Moderna’s next-generation Covid-19 vaccine, which is a component of the combination flu-Covid shot, by the end of the month. Moderna has previously said it does not expect a delay in that decision.

Moderna in early May pushed back the time frame for likely approval of its combination vaccine – meant to protect adults aged 50 and above against both Covid-19 and influenza – to 2026.

The company has been banking on revenue from newer mRNA shots to make up for falling sales of its Covid vaccine and less-than-expected uptake of its respiratory syncytial virus vaccine, which sent its shares down nearly 60% last year.