Inclusion Criteria:  All HWs eligible to receive the COVID-19 vaccination according to the national guidelines of Ministry of Health (MoH).  HWs working at Batumi Republican Clinical Hospital, Vakhtang Bochorishvili Clinic, Academician N. Kipshidze Central University Clinic, Bokeria Tbilisi Referral Hospital, Caucasus Medical Centre, and Infectious Diseases and AIDS Center. HWs who have already been vaccinated with a single dose of vaccine against COVID-19 as part of the early COVID-19 vaccine rollout can be included.  Exclusion Criteria:  HWs who are not eligible for COVID-19 vaccination or have a contraindication to vaccination should not participate in the study. HWs who do not work at above mentioned hospitals HWs under 18 years of age. HWs who have already been vaccinated with two doses of vaccine against COVID-19 before enrolment