COVID-19 vaccination remains essential for healthcare professionals: clinical evidence from a Polish cross-sectional study
Related Experiment Video
Updated: May 5, 2026

COVID-19 Seroprevalence Test for IgG Antibody Levels Among Healthy Donors Across Different Pandemic Phases in Jeddah
Published on: June 24, 2025
Karolina Hoffmann1, Michał Michalak2, Marzena Jarząb3
1Department and Clinic of Internal Diseases and Metabolic Disorders, Poznan University of Medical Sciences, Poznań, Poland.
Introduction:
Six years after the emergence of SARS-CoV-2, vaccination remains still central to preventing severe COVID-19. The aim was to determine the impact of the vaccine type and number of doses on the course of COVID-19 infection among Polish healthcare professionals.
Methods:
From November 2021 to February 2022, 813 people took part in a survey, including 625 women (76.9%) and 188 men (23.1%).
Results:
743 respondents (91.39%) had no confirmed COVID-19 infection after taking one of the available vaccines. However, there was no significant relationship between the number of doses of the SARS-CoV-2 vaccine and the occurrence of coronavirus infections after their administration (p = 0.75). Among people vaccinated with three doses, COVID-19 was mild (75.92%). Only 2.86% of the vaccinated subjects required hospitalization due to COVID-19 vs. 30.76% among unvaccinated subjects (p < 0.0001).
Conclusion:
The type of preparation taken did not affect the re-infection with the coronavirus, its course and the risk of complications. Vaccinated people were significantly less likely to be hospitalized due to COVID-19. There was no significant relationship between the number of doses of the SARS-CoV-2 vaccine and the occurrence of COVID-19 after their administration.
Related Concept Videos
Vaccinations
Clinical Significance of Antibiotic Resistance
Healthcare Associated Infections II: Preventive Measures
The best practices for preventing healthcare-associated infections include hand hygiene, patient risk...
Vaccines
Standard Precaution
Hand hygiene is the most crucial means to prevent the transmission of disease. Employers are legally required to provide their workers with personal protective equipment (PPE) to minimize exposure or contact with...
Bias in Epidemiological Studies

