By Ahmed Aboulenein WASHINGTON (Reuters) -Use of Pfizer Inc’s COVID-19 oral antiviral treatment Paxlovid has jumped 315% over the past four weeks, the U.S. Department of Health and Human Services said on Tuesday, as health officials try to address unexpectedly light demand. Nearly 115,000 courses of the pills were dispensed during the first week of May, a senior health official said. The White House said last month it was aiming to expand access to treatments like Paxlovid by doubling the number of locations at which they are available. “In recent weeks we’ve gone from 20,000 sites with Paxlov…