U.S. military department heads were ordered Tuesday to “immediately” start getting their troops vaccinated against the virus that causes COVID-19, two days after the first COVID-19 vaccine received federal approval. Defense Secretary Lloyd Austin said in a memorandum made public Aug. 25 that the secretaries of all military departments must “immediately begin full vaccination” of all service members who aren’t already vaccinated. A timeline was not laid out in the memo, but Austin directed a rapid pace, telling the secretaries to “impose ambitious timelines for implementation.” Austin announced on Aug. 9 that all active-duty military members would have to get a COVID-19 vaccine. He said he would either wait until a vaccine was approved by drug regulators or, if that did not happen by mid-September, he would ask President Joe Biden for a waiver. The Food and Drug Administration (FDA) approved the Pfizer-BioNTech shot on Monday. Austin emphasized in the …