**5. Conclusions**

Overall, 45% of the healthcare professionals from the Castellón Province (Spain) consider that healthcare quality worsened during the first COVID-19 wave. The factors that negatively impacted healthcare quality were heavier workload and patients' complexity, both of which are related to human/material resources management and healthcare organization. Significant differences were observed according to health department, type of health service, and type of professional, and studies with bigger samples should deal with these variables in the future.

**Author Contributions:** Conceptualization, V.M.G.-C. and P.T.-R.; methodology, V.M.G.-C., D.M.- T., Á.C.-G. and L.A.P.; formal analysis, D.M.-T. and V.M.G.-C.; data curation, P.T.-R. and C.R.-M.; writing—original draft preparation, V.M.G.-C. and M.J.V.-C.; writing—review and editing, D.M.-T., L.A.P., Á.C.-G., P.T.-R. and C.R.-M. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** The first page of the survey included information on the study objective and methodology, along with a box with which the participants gave their informed consent, confirming that their participation was voluntary and anonymous.

**Data Availability Statement:** Data are available upon request to the authors.

**Conflicts of Interest:** The authors declare no conflict of interest.
