Moderna Inc. executives said on Thursday they believe a fourth COVID-19 vaccine shot will be needed late this year due to waning protection from earlier doses, which could push up sales in the second half of 2022. Chief Executive Stephane Bancel stressed that the company’s current sales projections for its Spikevax COVID-19 shot—$19 billion in 2022, up from its prior estimate of $18.5 billion—does not include any additional sales to the United States this year. “What is not clear today is what will the U.S. government decide to do for 2022. Will it be a private market, or a mix of private and free vaccines,” Bancel said. The company said it was in talks with countries for more vaccine orders this year. Moderna shares jumped 11 percent to $150.80 amid a fall in the broader markets on Thursday. The stock was down over 70 percent from its August peak over …