No, all published entries are visible to all participants in the project. However, you can create a new chapter, adjust the settings so only you can see its contents, and post your content there (note: this setting is only available to project starters). Keep in mind that projects on Weeva are invite-only, so what you publish will not be seen by anyone other than the participants in the project.
If you are making a secret announcement in the book (for example, the gender or name of a baby) and would like to keep it secret until the book is printed, contact our customer support team directly. They are more than happy to help with any privacy concerns you may have.