The development of mutations in virus is reported to happen during replication, especially for an mRNA type virus like SARS-COV-2
Viruses that encode their genome in RNA, such as SARS-CoV-2, HIV and influenza, tend to pick up mutations quickly as they are copied inside their hosts, because enzymes that copy RNA are prone to making errors
My question is do mutations occur while mass manufacturing inactivated viral vaccines?
Simply because the process of manufacturing inactivated vaccines replicate the virus in large quantities, there might be large number of mutations occurring. Will this make each batch different from one another? Or do they control the replication process to limit the mutations?