Assessing the Age-Specific Seroepidemiology of Varicella-Zoster Virus in Korea in the Post-COVID-19 Era Using an Acetone-Fixed Cell FAMA Assay
Year: 2026
Type: article
Study design: Observational Study
Abstract: BACKGROUND: In Korea, the National Immunization Program has recommended a single dose of varicella vaccine at 12-15 months since 2005. Nevertheless, varicella notification continued to rise through 2019, prompting sustained seroprevalence monitoring. This study aimed to assess nationwide varicella-zoster virus (VZV) immunity in Republic of Korea (South Korea) during 2023-2024. A total of 843 serum samples of individuals aged 0 to 88 years from 8 tertiary hospitals over the country were tested using the acetone-fixed cell fluorescent antibody to membrane antigen (FAMA) assay and a commercial glycoprotein enzyme-linked immunosorbent assay (gpELISA) kit. METHODS: To establish basis of the cutoff, the British standard for anti-VZV IgG was subjected to repeated testing by acetone-fixed cell FAMA, live-cell FAMA and gpELISA. RESULTS: Using the acetone-fixed cell FAMA cutoff of 1:16, which corresponded to a concentration of 50 mIU/mL as determined by repeated testing, the seroprevalence rate was 92.53% (95% confidence interval [CI], 90.55-94.11) by gpELISA and 93.71% (95% CI, 91.87-95.16) by acetone-fixed FAMA. Both assays demonstrated a strong negative correlation with VZV notification during 2023-2024 in Korea. Among all age groups, infants aged 0 years exhibited the lowest seroprevalence. When these infants were excluded, seroprevalence remained lowest in the 5-9- and 10-14-year groups. CONCLUSION: This trend appears to partially reflect the current VZV notification in 2024. High VZV notification has shifted from the 0-4-year group to the 10-14-year group, while in 5-9-year-olds remains high. These findings likely reflect the combined effects of post-coronavirus disease 2019 non-pharmaceutical interventions and an age shift related to primary vaccination. The consistent low seroprevalence observed in children aged 5-9 years may provide supportive evidence for considering the potential benefit of an additional varicella vaccine dose beyond the current single-dose schedule at 12-15 months, although further investigation is warranted.
Authors: Kyu-Ri Kang, Gyu-Won Cho, Hye-Sook Jeong, June-Woo Lee, Ah-Ra Kim, Hyunhye Kang, Dongsub Kim, Dong Ho Kim, Dong Hyun Kim, Jimyung Kim, Chung Hyun Nahm, Su Eun Park, Joonhong Park, Sun Min Lee, Eun Lee, Ae-chin Oh, Dae Sun Jo, Eun Young Cho, Ji Yeon Ham, Hyun-Woo Choi, Seung-Jung Kee, Hyun Mi Kang, Jin-Han Kang, Ui Yoon Choi, Soo-Young Lee
Institutions: Catholic University of Korea, Korea National Institute of Health, The Catholic University of Korea Seoul St. Mary's Hospital, Inha University, Kyungpook National University Hospital, Kyungpook National University, Inha University Hospital, Chungnam National University, Chungnam National University Hospital, Pusan National University Children's Hospital, Jeonbuk National University Hospital, Jeonbuk National University, The Catholic University of Korea Bucheon St. Mary's Hospital, Pusan National University Yangsan Hospital, Chonnam National University, Chonnam National University Hospital, Kyungpook National University Chilgok Hospital
Language: English
Subfield: Infectious Diseases
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $690
Award: G1052970462
OpenAlex ID: W7167635995