As someone who has worked as a unit secretary, I can say firsthand that previous experience can be extremely helpful in excelling in this role. While entry-level positions are available, having prior experience in an administrative or secretarial role can make a world of difference in productivity and efficiency.
Employers often prefer candidates with this kind of experience because they are more likely to know how to handle certain situations, are already familiar with the software tools commonly used in the field, and have a general understanding of what the job entails.
However, that doesn't mean someone without experience can't excel in this role with training and a commitment to learning on the job. Ultimately, it's up to the employer to decide what qualifications they seek in a unit secretary.