Common Actions Requiring an Updated Backup
Applies to: 
SQL Server
Azure SQL Managed Instance
If you perform regular log backups, any replication-related changes should be captured in the log backups. If you don't perform log backups, perform a backup of the publication, distribution, subscription, msdb, and master databases after making modifications to your replication schema or topology.
Publication Database
Backup the publication database after:
Creating new publications.
Changing any publication property, including filtering.
Adding articles to an existing publication.
Performing a publication-wide reinitialization of subscriptions.
Making a schema change on a published table.
Performing on-demand script execution with sp_addscriptexec (Transact-SQL).
Changing any article property.
Dropping any publications.
Dropping any articles.
Disabling replication.
Distribution Database
Backup the distribution database after:
Creating or modifying replication agent profiles.
Modifying replication agent profile parameters.
Changing the replication agent properties (including schedules) for any push subscriptions.
A new range of identities is assigned by the automatic identity range management feature.
Subscription Database
Backup the subscription database after:
Changing any subscription property.
Changing the priority for a merge subscription at the Publisher.
Dropping any subscriptions.
Disabling replication.
msdb Database
Backup the msdb system database at the appropriate node after:
Enabling or disabling replication.
Adding or dropping a distribution database (at the Distributor).
Enabling or disabling a database for publishing (at the Publisher).
Creating or modifying replication agent profiles (at the Distributor).
Modifying any replication agent profile parameters (at the Distributor).
Changing the replication agent properties (including schedules) for any push subscriptions (at the Distributor).
Changing the replication agent properties (including schedules) for any pull subscriptions (at the Subscriber).
Creating a DTS package associated with a transactional publication that uses transformable subscriptions (at the Distributor and Subscriber).
Adding or dropping a transformable subscription (at the Distributor and Subscriber).
master Database
Backup the master system database at the appropriate node after:
Enabling or disabling replication.
Adding or dropping a distribution database (at the Distributor).
Enabling or disabling a database for publishing (at the Publisher).
Adding the first or dropping the last publication in any database (at the Publisher).
Adding the first or dropping the last subscription in any database (at the Subscriber).
Enabling or disabling a Publisher at a Distribution Publisher (at the Publisher and Distributor).