The World Health Organization (WHO) has recently released an updated guideline for varicella vaccines, replacing the previous 2014 version.

The document provides updated global guidance on varicella vaccination, emphasizing the use of a two-dose vaccination schedule to achieve optimal immunity. It also validates the inclusion of a new vaccine strain, MAV/06, developed by GC Biopharma (South Korea), and allows for interchangeability between vaccines containing this strain and those using the commonly used Oka strain.

At the same time, the guideline supports the inclusion of vaccines containing this new strain in national immunization programs in regions with a high disease burden, as part of comprehensive disease control strategies.

Key Updates and Recommendations in the Guideline

• Validation of a new vaccine strain: The guideline confirms that the MAV/06 strain (used in GC Biopharma’s BARYCELA vaccine) is equivalent to the Oka strain, helping to expand global vaccine supply and enabling its integration into existing immunization schedules.
  
• Two-dose vaccination schedule: While a single dose provides good protection, the guideline emphasizes that two doses produce a more durable and optimal immune response. This standard schedule has already been adopted in several countries, including the United Kingdom.
  
• Public health strategy:
  The guideline reaffirms that varicella vaccination is the primary intervention for reducing severe disease and complications, and supports the introduction of varicella vaccines into Expanded Program on Immunization (EPI) schedules for children in regions where varicella remains a major public health concern.
  
• Replacement of the 2014 guideline: The new document updates the 2014 recommendations by incorporating new scientific evidence and global implementation experience.
  

WHO Validation of the MAV/06 Varicella Vaccine Strain

The MAV/06 varicella vaccine strain developed by GC Biopharma has been officially validated in the WHO Position Paper on Varicella Vaccines:

• Formally recognized by WHO as a standard varicella vaccine strain alongside the widely used Oka strain
  
• Interchangeability between strains is validated, strengthening global vaccine supply security and ensuring continuity of immunization programs
  
• The MAV/06 strain was officially included in the WHO Position Paper on varicella vaccination published on 21 November 2025
  

The WHO Position Paper on Vaccines serves as a globally endorsed reference for immunization policy, developed by the Strategic Advisory Group of Experts on Immunization (SAGE).

With its inclusion in the WHO guideline, BARYCELA Inj., GC Biopharma’s varicella vaccine containing the MAV/06 strain, has achieved international recognition as equivalent to Oka strain–based varicella vaccines.

WHO has also confirmed the interchangeability between MAV/06- and Oka-based varicella vaccines, allowing BARYCELA Inj. to be administered alongside existing varicella vaccines within a two-dose immunization schedule. BARYCELA Inj. is therefore regarded as a validated alternative vaccine in the global varicella vaccine market.

The safety and immunogenicity of the MAV/06 strain have been demonstrated in Phase III clinical trials of BARYCELA Inj. and published in reputable international scientific journals. These studies show robust immune responses and a favorable safety profile, supporting the vaccine’s inclusion in national immunization programs.

The validation of this new strain contributes to a more flexible global vaccine supply system by enabling strain interchangeability, thereby reducing the risk of supply shortages and improving supply continuity.

Ms. Jaewoo Lee, Head of Regulatory Science and Product Development at GC Biopharma, stated: “The inclusion of the MAV/06 strain in the WHO guideline for varicella vaccines marks a significant milestone in strengthening the global supply of varicella vaccines.

With our proven manufacturing capacity and strong international supply capabilities, we are committed to supporting global immunization efforts by ensuring reliable access to high-quality vaccines.”

The MAV/06 strain, independently developed by GC Biopharma in 1993, has been used for nearly 30 years in products such as Suduvax, Varicella, and most recently BARYCELA Inj.

In Vietnam, NAVIVA Group is the authorized distributor and supplier of BARYCELA Inj., the varicella vaccine containing the MAV/06 strain.

Source: Tuoi Tre Newspaper