Vietnam remains on alert for emerging avian influenza variants

The poultry sector is currently facing heightened disease risks due to the circulation of highly pathogenic avian influenza (HPAI) viruses, particularly those belonging to clades 2.3.4.4b and 2.3.2.1e.

Since the beginning of the year, sporadic outbreaks have been reported in several provinces, including Ha Tinh, Ninh Binh, and Dien Bien. These incidents have resulted in significant economic losses and forced authorities to cull large numbers of poultry to prevent further spread of the disease.

In response, the Vietnamese Government has approved the National Avian Influenza Prevention and Control Plan for the 2026-2030 period, with key targets including:

• Reducing the number of outbreaks by at least 30% compared with the average recorded during 2019–2025.
• Achieving 100% vaccination coverage in high-risk areas.
• Ensuring a minimum vaccination rate of 80% across the national poultry population.

Vaccination: A critical pillar of flock protection

Vaccination remains one of the most effective tools for establishing a strong immune barrier against avian influenza and safeguarding poultry health.

To maximize vaccine efficacy, poultry producers should pay close attention to the following technical considerations:

• Antigenic matching: Select inactivated vaccines (for example, H5N1 subtype vaccines) that demonstrate a high degree of antigenic similarity to the field strains circulating in the local area. Proper antigenic matching helps reduce the risk of immune escape caused by viral mutations.
• Maintaining protective antibody levels: For laying hens and breeder flocks with extended production cycles, oil-emulsion adjuvanted vaccines are often preferred. These formulations release antigens gradually, supporting longer-lasting immunity and extended protection.
• Ensuring proper vaccination practices: Vaccination schedules should be followed rigorously, with booster intervals typically ranging from four to five months depending on bird age and production type. Correct dosage, administration techniques, and handling procedures are essential to minimize adverse reactions and stress in vaccinated birds.

Building a comprehensive “Three-pillar” disease prevention strategy

Experience from major poultry-producing regions shows that vaccination alone is not sufficient to control avian influenza effectively.

A robust prevention program should integrate three key components:

1. Appropriate vaccination
2. Strict biosecurity
3. Effective flock management

1. Adhere to the “Five don’ts” principle

Vietnam’s livestock and veterinary authorities recommend strict compliance with the following measures:

• Do not conceal disease outbreaks.
• Do not trade or transport sick or dead poultry.
• Do not consume poultry that is sick, dead, or of unknown origin.
• Do not dispose of poultry carcasses improperly.
• Do not allow free-ranging poultry in outbreak-affected areas.

2. Strengthen on-farm biosecurity discipline

• Environmental disinfection: Apply agricultural lime around poultry houses and farm access points to help eliminate pathogens. Comprehensive farm disinfection using approved disinfectants should be conducted at least once per week.
• Replacement stock management: For pullets and replacement birds, a quarantine and acclimation period of approximately five to six days is recommended before vaccination. This allows birds to adapt to their new environment and reduces stress-related health issues.
• House cleaning and downtime: At the end of each production cycle, poultry houses should undergo thorough cleaning, washing, and disinfection. Producers should also strictly observe the required downtime period before introducing a new flock.

Prevention costs less than outbreak losses

Investments in vaccination programs and routine biosecurity measures are consistently far less costly than the economic losses associated with disease outbreaks.

As avian influenza viruses continue to evolve in Vietnam and across the region, maintaining strict biosecurity standards, implementing effective vaccination programs, and following sound management practices remain the most sustainable strategies for protecting poultry health, farm productivity, and producers’ livelihoods.