J Korean Med Sci.  2022 Mar;37(9):e70. 10.3346/jkms.2022.37.e70.

Booster BNT162b2 COVID-19 Vaccination Increases Neutralizing Antibody Titers Against the SARS-CoV-2 Omicron Variant in Both Young and Elderly Adults

  • 1Research Institute of Public Health, National Medical Center, Seoul, Korea
  • 2Department of Pediatrics, National Medical Center, Seoul, Korea
  • 3Department of Infectious Diseases, National Medical Center, Seoul, Korea
  • 4National Institute of Infectious Diseases, National Institute of Health, Korea Disease Control and Prevention Agency, Cheongju, Korea
  • 5Division of Infectious Diseases, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Korea
  • 6Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea


Concerns about the effectiveness of current vaccines against the rapidly spreading severe acute respiratory syndrome-coronavirus-2 omicron (B.1.1.529) variant are increasing. This study aimed to assess neutralizing antibody activity against the wild-type (BetaCoV/Korea/ KCDC03/2020), delta, and omicron variants after full primary and booster vaccinations with BNT162b2. A plaque reduction neutralization test was employed to determine 50% neutralizing dilution (ND 50 ) titers in serum samples. ND 50 titers against the omicron variant (median [interquartile range], 5.3 [< 5.0–12.7]) after full primary vaccination were lower than those against the wild-type (144.8 [44.7–294.0]) and delta (24.3 [14.3–81.1]) variants. Furthermore, 19/30 participants (63.3%) displayed lower ND 50 titers than the detection threshold (< 10.0) against omicron after full primary vaccination. However, the booster vaccine significantly increased ND 50 titers against BetaCoV/Korea/KCDC03/2020, delta, and omicron, although titers against omicron remained lower than those against the other variants (P < 0.001). Our study suggests that booster vaccination with BNT162b2 significantly increases humoral immunity against the omicron variant.


COVID-19 Vaccine; Immunity; Antibodies; Omicron Variant; Republic of Korea


  • Fig. 1 Neutralizing antibody titers against variants of SARS-CoV-2: Wild-type (BetaCoV/Korea/KCDC03/2020), delta, and omicron. The panels display the median ND50 values (A) overall and by age group against the (B) wild-type (BetaCoV/Korea/KCDC03/2020), (C) delta, and (D) omicron variants (younger group, < 60 years old; older group, ≥ 75 years old). Antibody titers ≤ 10 was considered below the detection threshold (broken line). Boxes in each panel span the interquartile range; the solid line in each box indicates the median while the vertical line denotes the 2.5 and 97.5 percentile values. Comparisons between groups were analyzed by Student’s t-test and Mann-Whitney U test.ND50 = 50% neutralization dilution, ns = not significant.Statistical significance of differences between groups are defined as: ns P > 0.05; **P < 0.01; ***P < 0.001.

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Multi-Faceted Analysis of COVID-19 Epidemic in Korea Considering Omicron Variant: Mathematical Modeling-Based Study
Youngsuk Ko, Victoria May Mendoza, Renier Mendoza, Yubin Seo, Jacob Lee, Jonggul Lee, Donghyok Kwon, Eunok Jung
J Korean Med Sci. 2022;37(26):e209.    doi: 10.3346/jkms.2022.37.e209.


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