Traditionally, viruses for vaccines have been grown in embryonated hen eggs. But new challenges introduced by the COVID-19 pandemic have encouraged and catalyzed innovations in the field of vaccine development. The biopharmaceutical industry has recognized an advantage in mammalian cell-culture systems as promising alternatives to egg-based vaccine production. Cell lines can be cultured to large quantities in bioreactors, allowing for much shorter lead times, a more controlled production process, and a higher grade of reproducibility through standardization. In this article,…