On November 21, 2025, the World Health Organization (WHO) officially included the MAV/06 chickenpox vaccine strain in the document guiding global vaccination policy for chickenpox, recognizing it as equivalent to the Oka strain – the foundation of most chickenpox vaccines today [1].
This is the first time a strain developed by South Korea has achieved this recognition level, expanding the selection of high-quality vaccines, especially for low- and middle-income countries.
The MAV/06 strain was independently developed by GC Biopharma from the late 1980s, undergoing multiple reductions in toxicity on human embryonic cell lines and guinea pigs.
The MAV/06 strain has good adaptability to cultured cells, low heat sensitivity and stable toxicity reduction [2].
The sequencing of the entire genome shows that the MAV/06 strain belongs to branch 2, in the same genetic group as the Oka strain, with a genographic structure and 42 characteristic SNP positions related to reduced toxicity, ensuring the safety and effectiveness of the vaccine [3].
Vaccines produced from the MAV/06 strain have been clinically tested multinationally and used more than 30 million doses in 30 years in South Korea and more than 20 countries in Latin America, Asia, including Vietnam, all not recording serious adverse reactions [4].
The new generation BARYCELA Inj. vaccine, produced from MAV/06, does not use antibiotics, improves safety and has been WHO-PQ since 2023.
Studies show that MAV/06 achieves a serum conversion rate of 97-100%, high antibody effectiveness and sustainability. Phase III clinical trials in Korea and Thailand confirmed that immunogenicity is not inferior to Oka vaccine [5].
Real effectiveness data in South Korea and Latin America recorded a 60-80% reduction in the number of cases, complications reduced by 92%, effectiveness with a two-dose regimen reached >98%, equivalent to the Oka vaccine [6,7,8,9].
WHO's recognition of the MAV/06 strain helps diversify chickenpox vaccine supply, reduce dependence on a single strain, and increase vaccination rates, contributing to protecting children globally.
BARYCELA Inj., the new generation chickenpox vaccine developed by GC Biopharma from MAV/06, achieves immune and safe effectiveness equivalent to Oka vaccine, which can be used in the current double-dose schedule [10].
In Vietnam, NAVIVA GROUP is the authorized unit to distribute the 2nd generation MAV/ 06 chickenpox vaccine called BARYCELA inj. (GC Biopharma - Korea) in Vietnam. With more than 21 years of experience in the field of vaccines and medical biological products, NAVIVA GROUP cooperates with medical facilities to enhance access to safe, effective, and quality vaccines for the community.
The unit commits to ensuring stable supply, strictly complying with the preservation and transportation process according to GSP/GDP standards; and at the same time accompanying activities to raise awareness about proactive and safe vaccination.
Consulting Hotline: 0905 584 666
Website: www.naviva.com.vn
⌂ Email: info@naviva.com.vn
References:
1. WHO position paper on varicella vaccines – November 2025
2. Hwang, K. (1992) ‘Marker Test for Attenuation of Varicella-Zoster Viruses Isolated in Korea’, J. of Kor. Soc. Of Virology, 22(2), pp. 105–109.
3. Moon, J.Y. et al.. Assessment of Attenuation of Varicella-Zoster Virus Vaccines Based on Genomic Comparison. J Med Virol 2023, 95.
4. Lee, Y.H. et al. (2022) ‘Global varicella vaccination programs’, Clinical and Experimental Pediatrics, 65(12), pp. 555–562.
5. Choi, U.Y. et al. (2021) ‘Immunogenicity and safety profiles of a new MAV/06 strain varicella vaccine in healthy children: A multinational, Multicenter, randomized, double-blinded, active-controlled phase III study’, Vaccine, 39(12), pp.1758–1764.
6. Maria L. et al. (2017) Varicella prevention in Costa Rica: impact of a one-dose schedule universal vaccination, Expert Review of Vaccines, 16:3, 229-234,
7. Choi, J.-K. et al. (2019) ‘Trends in varicella and herpes zoster epidemiology before and after the implementation of universal one-dose varicella vaccination over one decade in South Korea, 2003–2015’, Human Vaccines & Immunotherapeutics, 15(11), pp. 2554–2560.
8. Jung, J. et al. (2019) ‘Epidemiological impact of the Korean National Immunization Program on Varicella incidence’, Journal of Korean Medical Science, 34(7).
9. Lee YH. et al.. The Protective Effectiveness of 2-Dose Varicella Vaccination in Children in Korea: A Case-control Study. Pediatr Infect Dis J. 2023 Aug 1; 42(8): 719-722.
10. Kang, H.M. et al.. Safety of Interchanging the Live Attenuated MAV/06 Strain and OKA Strain Varicella Vaccines in Children. Vaccines 2023, 11, 1442
