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Sept 18 (Reuters) - Pfizer expects 24% of the U.S. population, or about 82 million people, to receive COVID-19 shots this year, CFO David Denton said at a conference on Monday, reiterating the vaccine maker's estimates from earlier this year.

The U.S. Food and Drug Administration has authorized updated COVID vaccines from Pfizer and its partner BioNTech, as well as from Moderna, as the country prepares to start a fall vaccination campaign. A third vaccine from Novavax is also under review.

During the last re-vaccination campaign, when most Americans had either already had the COVID virus or been previously vaccinated, only around 56.5 million people got the updated booster shots, according to federal data.

But last week, a Reuters/Ipos poll showed that about half of Americans are interested in getting an updated COVID vaccine.

Rival Moderna has also said it expects U.S. demand for the shots to reach 50 million to 100 million doses in the fall season.

Demand for COVID vaccines has dropped sharply since 2021, when they first became available.

Pfizer had said in August it will launch a cost-cutting program if its COVID vaccine and antiviral treatment keep underperforming expectations in the coming months due to plunging demand.

At the J.P.Morgan U.S. All Stars Conference, Denton said Pfizer will provide more details on its cost-cutting measures in the second half of the year.

"We want to make sure that we're investing appropriately based on our R&D pipeline and the investments that we're making and bets that we made... are aligned to the revenue performance of the company long term," said Denton. (Reporting by Bhanvi Satija, Manas Mishra and Mariam Sunny in Bengaluru; Editing by Krishna Chandra Eluri and Pooja Desai)