show Abstracthide AbstractThe FDA-approved Adenovirus (Ad) Type 4 and Type 7 vaccine is highly effective and essential in preventing outbreaks of acute respiratory diseases (ARD) in U.S. military recruits. Our next-gen sequencing data revealed the presence of a previously undetected mutant strain of the Ad Type 4 (Ad4) component of the licensed vaccine which contains a single amino acid substitution (P388T) in the pre-terminal protein (pTP).