Background: Vaccination remains the leading strategy against Covid-19 worldwide. BNT 162b2 (tozinameran) belongs among first licensed vaccines with good efficacy. However, the role of monitoring both, antibodies and cell immunity after vaccination remains unclear. Methods: We conducted a 6-month prospective study involving vaccinated workers of NCCC in Slovakia who were tested for the presence of neutralizing antibodies and cell immunity after second dose of tozinameran. SARS-CoV-2 IgG antibodies were detected by the Atellica IM sCOVG, a fully automated 2-step sandwich immunoassay using indirect chemiluminescent technology. Blood samples were tested by two IGRA tests (Quantiferon RUO and CoviFeron) to assess interferon-γ (IFN-γ) responses to SARS CoV-2 spike protein antigen and nucleocapsid protein antigen. Results were stratified by gender and body mass index. P values for categorical variables were calculated using χ² or Fishers exact test. P values for continuous variables were calculated using T test and Wilcoxon-Mann-Whitney test. Value of statistical significance was set to 0.05. Data were analyzed using SAS 9.4 software. Results: Medical records of 94 respondents (71 females) were analyzed. Mean age was 40.2 years (23 – 62 years) and mean body mass index (BMI) ± standard error of mean (SEM) was 26.4±2.7 (21.3 – 31.7). Twenty-two (23.4 %) respondents had Covid-19 before first, 5 (5.3 %) before second, and 2 (2.15 %) after second dose of vaccine (P < 0.0001). IgG were tested 24.4±5.0, 50.2±12.1, and 187.9±12.8 days after second vaccination. IgG index progressively decline with corresponding values 126.81±40.34, 93.55±51.29, and 17.68±29.07 (P < 0.0001). Mean time from second vaccination to cell immunity testing was 157.2±101.3 days. Forty-eight (51.1 %) of respondents had negative, 6 (6.4 %) border line, and 40 (42.6 %) positive cell immunity (P < 0.0001). Conclusions: Our study confirmed the efficacy of tozinameran despite both, rapid decline of antibodies and absence of cell immunity in majority of subjects.