By Patrick Wingrove

(Reuters) -Moderna on Wednesday announced it was scaling down manufacturing of its COVID-19 vaccine, an updated version of which was approved this week by U.S. regulators, to align with lower post-pandemic demand and help the company sooner hit its target of 75% to 80% gross margin growth.

Moderna is in talks with its partners that fill vials and syringes with its messenger RNA-based COVID vaccines globally to downsize production, Stephen Hoge, president of the Massachusetts-based company, said in an interview.

The downsizing, Hoge added, will help Moderna adjust to the endemic phase of the disease, which had led to falling demand for COVID vaccines as payers scale back orders for the shots.

Moderna predicted in August that U.S. demand for the vaccine would reach 50 to 100 million doses in the fall season. About 153.8 million COVID shots were administered in the United States in 2022, according to the U.S. Centers for Disease Control and Prevention.

"Over the past couple of years, we've been in pandemic mode producing a billion doses a year," Hoge said. "We've been waiting for the moment when the pandemic was officially behind us that we would need to restructure that manufacturing footprint."

Following the U.S. Food and Drug Administration's authorization on Monday, Moderna said it would start shipping COVID vaccine doses across the United States.

The company has deals to supply other countries with its COVID shot including Britain, Canada and Japan, but does not yet have an agreement with the EU, according to Hoge, who also said COVID was the focus of Moderna's manufacturing agreement with China.

Hoge said that while Moderna was urgently working on downsizing COVID manufacturing, talks with third-party manufacturers - which will help produce the upcoming respiratory syncytial virus (RSV) and influenza vaccines that investors hope will start to replace Moderna's waning COVID revenue - could spill into next year.

"These are relationships that we will need for decades to come," Hoge said.

Moderna declined to identify the partners but has previously said they include Thermo Fisher, Sanofi and Catalent.

Moderna also announced on Wednesday that it had completed the regulatory submission for its RSV shot, and that its flu vaccine had generated a stronger immune response against all four A and B strains of the virus compared to traditional flu shots in a late-stage trial.

The effectiveness of Moderna's flu vaccine was demonstrated across all age groups, including older patients, and was found to be safe and tolerable, according to the company. Moderna also said it had found that its shot was equal or superior to Sanofi's high-dose flu vaccine in a separate early head-to-head study.

Shares of the vaccine maker were up nearly 3% to $108.50 in premarket trading.

(Reporting by Patrick Wingrove in New York; Additional reporting by Bhanvi Satija in Bengaluru; Editing by Will Dunham)