Relative Effectiveness of COVID-19 Vaccination in Healthcare Workers: 3-Dose Versus 2-Dose Vaccination |
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| Authors: | Sung Ran Kim Hyeon Jeong Kang Hye Rin Jeong Su Yeon Jang Jae Eun Lee Da Eun Kim Hae Ry Lee Min Hee Cho Ji Yun Noh Hee Jin Cheong Woo Joo Kim Joon Young Song |
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| Affiliation: | 1.Infection Control Team, Korea University Guro Hospital, Seoul, Korea.;2.Division of Infectious Disease, Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea.;3.Vaccine Innovation Center-KU Medicine (VIC-K), Seoul, Korea. |
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| Abstract: | The omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is known to have high infectivity and is more likely to evade vaccine immunity. However, booster vaccination is expected to strengthen cross-reactive immunity, thereby increasing the vaccine effectiveness (VE). This study aimed to evaluate the relative VE of the 3-dose (booster) vaccination compared with the 2-dose primary series vaccination in healthcare workers during omicron variant-dominant periods. During the omicron-dominant period from February 1, 2022 to February 28, 2022, a 1:1 matched case-control study was conducted. Healthcare workers with positive SARS-CoV-2 test results were classified as positive cases, whereas those with negative results served as controls. Compared with the 2-dose primary series vaccination, booster vaccination with mRNA vaccine showed moderate VE (53.1%). However, in multivariate analysis including the time elapsed after vaccination, the significant VE disappeared, reflecting the impact of recent vaccination rather than the third dose itself. |
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| Keywords: | SARS-CoV-2 COVID-19 Healthcare Worker Vaccine Effectiveness |
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