Résumé
BACKGROUND COVID-19 vaccines help protect against infection, severe illness, hospitalization and death. When someone who is vaccinated with either a primary series or a primary series plus a booster dose gets infected with the virus that causes COVID-19, it is referred to as a vaccine breakthrough infection. OBJECTIVES To assess the frequency and clinical characteristics of breakthrough cases of COVID-19 infection and to study the predictive risk factors. SUBJECTS&METHODS A cross-sectional study was carried out including 604 undergraduate medical and non-medical students in Iraq from 10th of August to 29th of September 2022. Data was collected via an online specific questionnaire and analyzed to estimate the frequency of COVID-19 breakthrough cases post vaccination, and number of doses of vaccine used. The association of different factors including age, gender, grade, body mass index, smoking, and comorbidity was also studied as predictive risk factors. We used the data to formulate tables, figures and perform statistical tests in IBM SPSS Statistics 25. RESULTS Mean age of study sample was 21.78 year (3.26) and 339 (56%) were females. In terms of COVID-19 vaccination data, 97 (16%) have received one dose, 459 (76%) two doses and 48 (8%) three doses. Regarding PCR test, 74 (12%) were positive after the first dose compared to 49 (8%) after the second dose. About the symptoms developed, the most frequent were fever in 372 (61.1%), unusual fatigue in 96 (15.79%), chills in 29 (4.77%) and persistent cough in 26 (4.28%). For most predictive factors, results were statistically insignificant. CONCLUSIONS In current study; demographic factors showed no statistically significant impact on prevalence of COVID-19 breakthrough cases. Despite this; number of participants who develop symptoms after the second dose of vaccine was high; and having 3 or more symptoms. About half of participants showed symptoms even after being fully vaccinated.