Inclusion Criteria:  All Health Workers eligible to receive the COVID-19 vaccination according to the national guidelines of Institute of Public Health. Health Workers working at Tirana University Hospital "Mother Theresa", University Hospital "Shefqet Ndroqi", Durres Regional hospital and Fier Regional Hospital. Health Workers who have already been vaccinated against COVID-19 as part of the early COVID-19 vaccine rollout can be included, as long as information can be collected about the date and type of the vaccine that was administered. However, priority will be given to enrolling Health Workers who have received their COVID vaccine no more than 4 days prior to the day of enrolment in the study.  Exclusion Criteria:  Health Workers who are not eligible for COVID-19 vaccination or have a contraindication to vaccination should not participate in the study. Health Workers who do not work at Tirana University Hospital "Mother Theresa", University Hospital "Shefqet Ndroqi", Durres Regional hospital and Fier Regional Hospital.