Differential Genome Replication of a Unique Single-Amino-Acid Mutation in the Adenovirus-4 Component of the Live Oral Adenovirus Type 4 and Type 7 Vaccine

The FDA-approved Adenovirus Type 4 and Type 7 Vaccine, Live, Oral is highly effective and essential in preventing acute respiratory diseases (ARDs) in U.S. military recruits. Our study revealed the presence of a previously undetected mutation, not found in the wild-type human adenovirus type 4 (HAdV-4) component of the licensed vaccine, which contains an amino acid substitution (P388T) in the pre-terminal protein (pTP). This study demonstrated that replication of the T388 HAdV-4 vaccine mutant virus is favored over the wild type in WI-38 cells, the cell type utilized in vaccine manufacturing. However, results from serial human stool specimens of vaccine recipients support differential genome replication in the gastrointestinal tract (GI), demonstrated by the steady decline of the percentage of mutant T388 vaccine virus. Since vaccine efficacy depends upon GI replication and the subsequent immune response, the mutation can potentially impact vaccine efficacy.

Automated summary

The FDA-approved Adenovirus Type 4 and Type 7 Vaccine is highly effective in preventing acute respiratory diseases in U.S. military recruits. Our study found a previously undetected mutation in the component of the licensed vaccine, which may affect vaccine efficacy as it favors replication in certain cells but declines in the gastrointestinal tract.