WASHINGTON—Delta Air Lines Inc’s chief executive asked the head of the U.S. Centers for Disease Control and Prevention on Tuesday to shrink quarantine guidelines for fully vaccinated individuals who experience breakthrough COVID-19 infections, citing the impact on the carrier’s workforce. CEO Ed Bastian, along with the company’s chief health officer and a medical adviser, asked in a letter to CDC Director Rochelle Walensky seen by Reuters that the agency’s recommended quarantine period for anyone who tests positive with a breakthrough COVID-19 infection be reduced to five days from the current 10. The letter suggested that individuals could end isolation with appropriate testing. White House medical adviser Anthony Fauci said on Tuesday that U.S. health authorities are considering reducing the 10-day recommended quarantine period for Americans testing positive for COVID-19 as the Omicron variant tears across the country. The CDC declined to comment. “With the rapid spread of the Omicron variant, …